Thermal Spray Coating for Mechanical Face Seals

TECHNICAL FIELD

This disclosure relates generally to the field of mechanical components formed by a material deposition process, and more particularly to a mechanical seal formed using a laser cladding process or a thermal spray coating process.

BACKGROUND

In equipment and machinery that have rotatable shafts, seals are often utilized to retain lubricant while at the same time excluding foreign matter from bearing surfaces of the rotatable shafts. In particular, metal or mechanical face seals are used in heavy duty rotating applications, such as axles, gearboxes, tracked vehicles, conveyer systems, etc., where components are exposed to hostile, abrasive, and corrosive environments where shaft seals may quickly wear out. The mechanical face seals generally include two identical metal seal rings that are mounted face-to-face with one another in two separate housings or retainers. One of the two metal rings typically remains static within its respective retainer while the other of the two metal rings typically rotates with its counter face.

Due to the operational requirements and the wide range of environmental conditions in which these components operate in, the metal contact surfaces of the mechanical face seals may be subject to accelerated wear and tear due to frictional contact, stresses, and temperature extremes, among other things. As a result, the mechanical face seals may be made from more durable and exotic materials. However, such materials are expensive and are difficult to form.

U.S. Patent Application Publication No. 2011/0285091 (the '091 Publication), entitled “Method for Applying Wear Resistant Coating to Mechanical Face Seal,” purports to address the problem of reducing cost while maintaining desired corrosion and wear resistant. However, coating processes in related art have suffered from significant failure of adhesion. Accordingly, there is a need for an improved process for forming mechanical components such as face seals.

SUMMARY

In one aspect, the present disclosure describes a method of producing a mechanical face seal. The method may include forming a cast or wrought substrate part, the substrate part having an inner diameter, an outer diameter, and a planar surface extending between the inner diameter and the outer diameter. The method may include roughing the planar surface of the substrate part. The method may include applying a coating material onto the planar surface to form a thermal coating layer on the substrate part, the coating material comprising at least one of a Fe-based alloy, a Ni-based alloy, a Co-based alloy, a carbide-based material, and a ceramic material.

In another aspect, the present disclosure describes a method of producing a mechanical face seal, including forming a cast or wrought substrate part. The substrate part may have an inner diameter, an outer diameter, and a planar surface extending between the inner diameter and the outer diameter. The method may include roughing the planar surface of the substrate part to form pores, peaks, and valleys on the planar surface of the substrate part. The method may include spraying a coating material that has been heated to molten particles, via a heating element and a spray head, onto the planar surface to form a thermal spray coating layer on the substrate part, the coating material comprising at least one of a Fe-based alloy, a Ni-based alloy, a Co-based alloy, a carbide-based material, and a ceramic material.

In yet another aspect, the present disclosure describes a method of producing a mechanical face seal, including forming a cast or wrought substrate part, the substrate part having an inner diameter, an outer diameter, and a planar surface extending between the inner diameter and the outer diameter. The method may include roughing the planar surface of the substrate part. The method may include spraying a coating material via a sprayer onto the planar surface to form a thermal spray coating layer on the substrate part, the coating material comprising at least one of a Fe-based alloy, a Ni-based alloy, a Co-based alloy, a carbide-based material, and a ceramic material. The Fe-based alloy may consist of 0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon, 2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten, 1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to 0.03% phosphorus, up to 0.03% sulfur, and a balance of iron. The Ni-based alloy may consist of 16-17% chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0% carbon, and a balance of nickel. The Co-based alloy may consist of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20% tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, up to 1% manganese, and a balance of cobalt. The carbide-based material may include at least one of tungsten and chromium. The ceramic material may include at least one of aluminum oxides, cobalt oxides, and titanium oxides.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements.

FIG. 1 is a perspective view of an exemplary machine in which the disclosed mechanical face seals may be used, the machine is depicted next to a full-sized sports utility vehicle.

FIG. 2 is a cutaway perspective view of a gearbox used in the exemplary machine of FIG. 1.

FIG. 3 is a cross-sectional view of a first seal assembly of the gearbox of FIG. 2.

FIG. 4 is a cross-sectional view of a second seal assembly of the gearbox of FIG. 2.

FIG. 5 is a cross-sectional view of an exemplary spring-loaded metal face seal.

FIG. 6 is a flow chart of steps for laser cladding a substrate part to form laser cladded mechanical face seals in accordance with an aspect of the disclosure.

FIG. 7 is a partial cross-sectional view of an exemplary substrate part being formed in accordance with an aspect of the disclosure.

FIG. 8 is a partial cross-sectional view of the exemplary substrate part of FIG. 7 after exposing a laser to a planar surface of the substrate part and supplying a coating material to the planar surface in accordance with an aspect of the disclosure.

FIG. 9 is a partial cross-sectional view of the substrate part in FIG. 8 depicting a section of a coating surface that may be removed during a finishing process.

FIG. 10 is a partial cross-sectional view of the substrate part in FIG. 8 depicting an inner diameter side and an outer diameter side that may be removed during a finishing process.

FIG. 11 is a flow chart of steps for thermal spray coating a substrate part to form thermally spray coated mechanical face seals in accordance with an aspect of the disclosure.

FIG. 12 is a partial cross-sectional view of an exemplary substrate part being formed in accordance with an aspect of the disclosure.

FIG. 13 is a partial cross-sectional view of the exemplary substrate part of FIG. 12 after supplying a thermal spray coating to a planar surface of the substrate part in accordance with an aspect of the disclosure.

FIG. 14 is a partial cross-sectional view of the substrate part in FIG. 13 depicting a section of a thermal spray coating surface that may be removed during a finishing process.

DETAILED DESCRIPTION

Now referring to the drawings, FIG. 1 shows an exemplary machine 10 in related art where mechanical face seals may be used to provide a dynamic seal. The machine 10 may be in the form of a mining truck and is depicted next to a full-sized sports utility vehicle 12 to show and compare a size and scale of the two machines. The machine 10 is typically employed to transport a payload of several hundred tons and operates in extreme environmental conditions. The environmental and payload demands exceed typical demands placed on machinery in other fields and therefore components must be designed and built to withstand the extreme conditions and demands.

The machine 10 may be driven by an internal combustion engine (not shown) or other suitable power plant. The engine or suitable power plant may be activated to provide motive force to rotatably drive a wheel hub 11 and associated tires 13 of the machine 10. As shown in FIG. 2, a wheel gear unit 14 in the related art may be interposed between the engine of the machine 10 and the wheel hub 11 to provide an appropriate amount of output torque and speed. The wheel gear unit 14 includes a flange 17 that may be used to mount the wheel hub 11.

It should be noted that the machine 10 shown in FIG. 1 and reference to seals is for the purpose of brevity. The material deposition processes of the present disclosure may be utilized with any type of machine and any type of mechanical component in such a machine that may be subject to operation in extreme environmental conditions. In one non-limiting aspect, the seals produced using the material deposition processes of the present disclosure may be used in undercarriage type applications, which may include track rollers, carrier rollers, and idlers.

Referring to FIG. 2, the wheel gear unit 14 may include a first mechanical face seal assembly 100 and a second mechanical face seal assembly 200. The first mechanical face seal assembly 100 and the second mechanical face seal assembly 200 provide fluid seals to components of the wheel gear unit 14. Leaks or failure at the mechanical face seal assemblies 100, 200 may be detrimental to internal components of the wheel gear unit 14 and may result in accelerated wear and tear, equipment failure, and downtime required for cleaning, repairing, or maintaining the equipment.

Turning to FIG. 3, the first mechanical face seal assembly 100 may include a fixed retainer 102, a rotating retainer 104, a rotating seal ring 110, and a static seal ring 112. An O-ring 108 may be provided between the fixed retainer 102 and the static seal ring 112, and between the rotating retainer 104 and rotating seal ring 110. The fixed retainer 102 and the rotating retainer 104 may each include angled surfaces to compress their respective O-rings 108. In response to the compression force, the O-rings 108 may press the rotating seal ring 110 and the static seal ring 112 against each other such that the rotating seal ring 110 applies a frictional torque on the static seal ring 112, thereby forming a fluid seal at interface 106. While a Duo-Cone™ mechanical face seal is shown in FIGS. 3 and 4 and a spring-loaded metal face seal arrangement is shown in FIG. 5, a laser cladding process or a thermal spray coating process of the present disclosure, as will be described in further detail below, may be performed on any suitable mechanical face seal, including but not limited to heavy duty dual face (HDDF) seals.

Turning to FIG. 4, the second mechanical face seal assembly 200 may include a fixed retainer 202, a rotating retainer 204, a static seal ring 210, and a rotating seal ring 212. An O-ring 208 may be provided between the fixed retainer 202 and the static seal ring 210, and between the rotating retainer 204 and rotating seal ring 212. The fixed retainer 202 and the rotating retainer 204 may each include an angled surface to compress their respective O-rings 208. In response to the compression force, the O-rings 208 may press the static seal ring 210 and the rotating seal ring 212 against each other such that the rotating seal ring 212 applies a frictional torque on the static seal ring 210, thereby forming a fluid seal at interface 206.

The rotating seal ring 110 and the static seal ring 112 together form a first mechanical face seal 120. The static seal ring 210 and the rotating seal ring 212 together form a second mechanical face seal 220. As discussed above, a rotational torque may be applied at the interface 106 of the first mechanical face seal 120, via rotation of the rotating seal ring 110, and at the interface 206 of the second mechanical face seal 220, via rotation of the rotating seal ring 212, while the wheel gear unit 14 is driven. The seal rings 110, 112, 210, 212 may each be made of cast iron. However, due to the constant rotational torque and frictional contact experienced at the interfaces 106, 206, and due to the extreme operating conditions when utilized in applications such as the machine 10, the seal rings 110, 112, 210, 212 require regular maintenance and replacement, leading to prolonged downtime of the machine 10.

Turning to FIG. 5, a spring-loaded metal face seal arrangement 250 is shown. The spring-loaded metal face seal arrangement 250 may be used in the machine 10 to retain lubricant and/or coolant within components of the machine 10 and to prevent intrusion of any debris of foreign matter into the components of the machine 10. The spring-loaded metal face seal arrangement 250 may be used to provide a seal between a rotatable and a stationary structure, or between relatively rotatable structures, such that a constant and precise axial sealing force is applied.

The spring-loaded metal face seal arrangement 250 may be installed between a first rotatable structure 260 and a second rotatable structure 265. The spring-loaded metal face seal arrangement 250 may include a first seal retainer 252 and a second seal retainer 254, which are respectively attached to the first rotatable structure 260 and the second rotatable structure 265. The spring-loaded metal face seal arrangement 250 may include at least a first seal ring 270, a second seal ring 280, and a spring member 290. In select aspects, the spring member 290 may include one or more Belleville springs.

The first seal ring 270 may include a first axially facing sealing surface 272 and a first axially facing recessed surface 274. In select aspects, the first axially facing sealing surface 272 and the first axially facing recessed surface 274 may define a stepped portion. Additionally or alternatively, a sloped ramped portion may extend between the first axially facing sealing surface 272 and the first axially facing recessed surface 274. In select aspects, the first axially facing recessed surface 274 may consist of a sloped portion that extends laterally from the axially facing sealing surface 272.

The second seal ring 280 may include a second axially facing sealing surface 282 and a second axially facing recess surface 284. In select aspects, the second axially facing sealing surface 282 and the second axially facing recessed surface 284 may define a stepped portion. Additionally or alternatively, a sloped ramped portion may extend between the second axially facing sealing surface 282 and the second axially facing recessed surface 284. In select aspects, the second axially facing recessed surface 284 may consist of a sloped portion that extends laterally from the axially facing sealing surface 282.

The first seal ring 270 and the second seal ring 280 may be disposed such that the first axially facing surface 272 and the second axially facing surface 282 are opposed face-to-face. The spring member 290 may provide an axial force to enable substantially constant engagement between the first axially facing surface 272 and the second axially facing surface 282. While the spring member 290 enables substantially constant engagement even as the first axially facing surface 272 and the second axially facing surface 282 wear down, the spring-loaded metal face seal arrangement 250 will still require regular maintenance and replacement due to the extreme operating conditions in which the machine 10 is operated.

While efforts have been made to make seal rings out of more exotic materials that are more capable of resisting wear, those materials are substantially more expensive, and are more difficult and time intensive to form into the required geometries of the mechanical face seals. Additionally, attempts have been made in the related art to coat mechanical face seals using twin-wire arc (TWA) spray, diamond-like coatings (DLC), or high velocity oxygen fuel (HVOF). However, prior methods in the related art have led to coatings that lacked durability, delaminated from the substrate, and/or lead to unacceptable surface cracking or similar failure. Accordingly, there is a need for more durable and cost effective coating processes.

Referring to FIGS. 6 and 7, the disclosure provides a method of forming mechanical face seals using a laser cladding process that may enable use of less expensive substrates, increase performance, and reduce manufacturing complexity over conventional techniques and/or seal rings made of expensive exotic wear resistant substrates such as titanium or zirconium. The method of laser cladding 300 may include an obtaining step 310 to obtain or form a substrate part 400. In the obtaining step 310, the substrate part 400 may be wrought or cast using an SAE 52100 alloy steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron, or grey cast iron. Other materials are contemplated as well. The substrate part 400 may be wrought or cast to have roughly a geometry of a finished mechanical face seal. In addition, or as an alternative, the substrate part 400 may be formed by a powder metallurgy or other suitable process. In select aspects, the obtaining step 310 may comprise refurbishing, repairing, or salvaging a previously used or damaged substrate part in order to obtain the substrate part 400.

After the substrate part 400 has been obtained, the substrate part 400 may undergo a preheating step 320. The preheating step 320 may include heating the substrate part 400 in an oven, applying resistive heating to the substrate part 400, applying a suitable coil to promote induction heating of the substrate part 400 and/or a like heating process. In select aspects, the suitable coil may be a U-shaped coil or a pancake coil. In select aspects, a laser 800 may be exposed to a top layer 441 of the substrate part 400 to heat at least a planar surface 440 of the substrate part 400.

An exposing step 330 may be performed whereby the surface of the substrate part 400 is exposed to the laser 800, either for the first time, or a subsequent time if a preheating step 320 is performed by the laser 800. During the exposing step 330, the laser 800 may trace along the top layer 441 of the substrate part 400 and at least partially melt the top layer 441 of material of the substrate part 400.

A supplying step 340 may be performed just before, during, or just after the exposing step 330 begins. During the supplying step 340, a coating material 950 is supplied to the top layer 441 of the substrate part 400 at or near a location of the laser 800 being traced on the planar surface 440, whereby the top layer 441 of the substrate part 400 is melted together with the coating material 950 via the laser 800 to form an intermediate layer 500. The intermediate layer 500 may include both the coating material 950 and a material of the substrate part 400, as shown in FIG. 8. The supplying step 340 may further include supplying the coating material 950 to be melted by the laser 800 to form a cladding layer 600 disposed above the intermediate layer 500, as shown in FIG. 8. In one aspect, the exposing step 330 and/or the supplying step 340 may be performed to form the cladding layer 600 without or substantially without any cracks or any defects, such as oxides or pores.

A finishing step 350 may be performed on the substrate part 400 to achieve final dimensions required by a particular mechanical face seal. The finishing step 350 may also be performed on the intermediate layer 500 and/or the cladding layer 600 formed during the supplying step 340. The finishing step 350 may comprise a surface finishing process which may include one or more of grinding, polishing, milling, machining, or other suitable process to finish one or more surfaces of the substrate part 400. The surface finishing process of the finishing step 350 may be performed to refine one or more of a surface texture, thickness, inner diameter, outer diameter and/or similar feature of the substrate part 400 to obtain final dimensions that correspond to a finished metal face seal. The finishing step 350 may comprise a heat treatment process, which may be performed before or after the surface finishing process, to enhance material properties of the substrate part 400. The heat treatment process may include thermal hot flattening where the substrate part 400 is compressed in a thermally controlled environment to relieve product stresses. In one aspect, the exposing step 330 and/or the supplying step 340 may be performed to form the cladding layer 600 without or substantially without any cracks, and such that cracks do not form in the cladding layer 600 during the finishing step 350.

Referring to FIG. 7, the substrate part 400 may include at least an outer diameter surface 410 and an inner diameter surface 420 extending along a common central axis 430. The substrate part 400 may include a planar surface 440 extending between the outer diameter surface 410 and the inner diameter surface 420. When processed and finished, the planar surface 440 of the substrate part 400 may form a surface of a mechanical seal ring for contact at an interface between two mechanical face seals. As discussed above with respect to the obtaining step 310, the substrate part 400 may be wrought or cast using an SAE 52100 alloy steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron, or grey cast iron. In select aspects, the obtaining step 310 may comprise refurbishing, repairing, or salvaging a previously used or damaged substrate part in order to obtain a substrate part 400.

During the obtaining step 310, the substrate part 400 may be formed into a ring-shaped element. In select aspects, the substrate part 400 may be made of SAE 52100 alloy steel, which may have a chemical composition of 1.3% to 1.6% chromium, 0.93% to 1.1% carbon, 0.25% to 0.45% manganese, 0.15% to 0.35% silicon, up to 0.025% sulfur, up to 0.025% phosphorous, and a balance of iron. In select aspects, the substrate part 400 may be made of SAE 1020 alloy steel, which may have a chemical composition of 0.18% to 0.23% carbon, 0.3% to 0.6% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In select aspects, the substrate part 400 may be made of SAE 1040 alloy steel, which may have a chemical composition of 0.37% to 0.44% carbon, 0.6% to 0.9% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In select aspects, the substrate part 400 may be made of ductile iron, which may have a chemical composition of 3.0% to 3.9% carbon, 1.7% to 2.9% silicon, 0.1% to 0.6% manganese, 0.02% to 0.06% magnesium, 0.005% to 0.04% phosphorus, up to 0.04% sulfur, up to 0.4% copper, and a balance of iron. In select aspects, the cast iron substrate may be made of grey cast iron, which may have a chemical composition of 2.5% to 4.0% carbon, 1% to 3% silicon, and a balance of iron.

During a laser cladding process, the substrate part 400 may be preheated, as discussed in the preheating step 320 described above. The substrate part 400 may be heated in an oven, resistively heated, inductively heated via a pancake coil or other suitable induction coil, or heated by exposing the top layer 441 of the substrate part 400 to the laser 800. In select aspects, the laser 800 may trace over the planar surface 440 to heat up at least the top layer 441 of the planar surface 440.

After the substrate part 400 has been obtained, the exposing step 330 may be performed, which may occur with or without performance of the preheating step 320. During the exposing step 330, the laser 800 may trace along the planar surface 440 of the substrate part 400 causing the top layer 441 of the planar surface 440 to at least partially melt. In select aspects, the exposing step 330 may include adjusting or controlling a power level of the laser 800.

Concurrently with or just after the exposing step 330, as the laser 800 traces over at least one portion 442 of the top layer 441, the supplying step 340 may be performed to supply the coating material 950 to the portion 442 of the planar surface 440 at or near a location of the laser 800 traced on the planar surface 440. The supplied coating material 950 may be fed through a supplier 900, which is positioned to deliver the coating material 950 at or near the portion 442 of the planar surface 440 being traced by the laser 800. In select aspects, the supplier 900 may be attached to a laser generator 850 that generates the laser 800. In select aspects, the supplier 900 may be integral with the laser generator 850, as shown in FIG. 7. In select aspects, the supplying step 340 may include controlling a feed rate of the coating material 950 via the supplier 900.

The coating material 950 may be in the form of a wire or a powder, and the coating material 950 may be made of Fe-based alloys, Ni-based alloys, and/or Co-based alloys. In select aspects, the coating material 950 may include Durmat® 60A, M2 tool steel, Stellite® 1, Stellite® 6, or other suitable material. In select aspects where the coating material 950 is supplied in the form of a wire, the wire may be heated prior to being supplied to the planar surface 440. In select aspects, the coating material 950 may consist of a Ni-based alloy having a chemical composition of 16-17% chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0% carbon, and a balance of nickel. In select aspects, the coating material 950 may consist of a Fe-based alloy having a chemical composition of 0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon, 2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten, 1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to 0.03% phosphorus, up to 0.03% sulfur, and a balance of iron. In select aspects, the coating material 950 may consist of a Co-based alloy having a composition of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20% tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, up to 1% manganese, and a balance of cobalt.

The supplier 900 may be configured to feed a spool of the wire of the coating material 950 or to spray a stream of powder of the coating material 950 to the portion 442 of the planar surface 440. As the coating material 950 is supplied to the portion 442 of the planar surface 440, during the supplying step 340, heat from the laser 800 and/or the melted top layer 441 of the planar surface 440 may cause the coating material 950 to melt and mix with the top layer 441 of the planar surface 440, thereby forming an intermediate layer 500, as shown in FIG. 8. The intermediate layer 500 may include a mix of both the coating material 950 and the material of the substrate part 400.

The supplying step 340 may further supply coating material 950 to be melted by the laser 800 and/or heat from the intermediate layer 500 to form a cladding layer 600 disposed above the intermediate layer 500, as shown in FIG. 8. In select aspects, the cladding layer 600 may include primarily the coating material 950 or may include exclusively the coating material 950. In select aspects, a thickness of the intermediate layer 500 and the cladding layer 600 together may form a coating surface 450 on the substrate part 400 that is at least 0.1 μm thick.

Turning to FIGS. 9 and 10, once the intermediate layer 500 and the cladding layer 600 have been formed on the substrate part 400, the finishing step 350 may be performed to obtain final dimensions that correspond to a finished metal face seal. As shown in FIG. 9, the finishing step 350 may comprise a surface finishing process which may include one or more of grinding, polishing, milling, machining, or other suitable process to remove material 710 from a top surface 605 of the cladding layer 600 to obtain final dimensions of a finished metal face seal. In select aspects, the finishing step 350 may comprise a heat treatment process, which may be performed before or after the surface finishing process, to enhance material properties of the substrate part 400. The heat treatment process may include thermal hot flattening where the substrate part 400 is compressed in a thermally controlled environment to relieve product stresses. In select aspects, the cladding layer 600 is finished to a cladding layer thickness of between 0.7 mm and 1.0 mm. The cladding layer 600 may have a Rockwell hardness of between HRC 60 and 65. In select aspects, the Rockwell hardness of the cladding layer 600 may be between 62 and 64. In select aspects, the top surface 605 of the cladding layer 600 is free of cracks.

As shown in FIG. 10, in select aspects, the finishing step 350 may include grinding, polishing, milling, machining, and/or other suitable machining process to remove material 720 from the outer diameter surface 410 of the substrate part 400, the intermediate layer 500, and/or the cladding layer 600 to obtain final dimensions that correspond to a finished mechanical face seal. In select aspects, the finishing step 350 may include grinding, polishing, milling, machining, and/or other suitable process to remove material 730 from the inner diameter surface 420 of the substrate part 400, the intermediate layer 500, and/or the cladding layer 600 to obtain final dimensions that correspond to a finished mechanical face seal.

Referring to FIGS. 11 and 12, the disclosure provides a method of forming mechanical face seals using a thermal spray coating process. The thermal spray coating process may enable use of less expensive substrates, less coating materials, increase performance, and reduce manufacturing complexity and cost in comparison with conventional techniques and/or seal rings made of expensive exotic wear resistant substrates such as titanium or zirconium. The method may further improve lubrication properties of the finished mechanical face seals in comparison with those produced using conventional techniques. The method of thermal spray coating 1000 may include an obtaining step 1010. Similar to the obtaining step 310 described above with respect to the method of laser cladding 300, the obtaining step 1010 may include obtaining or forming a substrate part 1100, which may be wrought or cast using an SAE 52100 alloy steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron, or grey cast iron. Other materials are contemplated as well and will be appreciated by those skilled in the art in view of the present disclosure. The substrate part 1100 may be wrought or cast to have roughly a geometry of a finished mechanical face seal. In addition, or as an alternative, the substrate part 1100 may be formed by a powder metallurgy or other suitable process. In select aspects, the obtaining step 1010 may comprise refurbishing, repairing, or salvaging a previously used or damaged substrate part in order to obtain a substrate part 1100. In select aspects, the substrate part 1100 may include a recessed or sloped surface adjacent to the planar surface 1140 for forming a final seal ring which be used in a spring-loaded metal face seal arrangement (such as the one shown in FIG. 5, for example).

After the substrate part 1100 has been obtained, the substrate part 1100 may undergo a rough surface treatment step 1020. The rough surface treatment step 1020 may include roughening of at least one surface to form an adhesion surface where the thermal spray coating may be applied onto. In select aspects, the rough surface treatment step 1020 may be applied to a planar surface 1140 of the substrate part 1100 to form pores, peaks, and valleys on the planar surface 1140, which may be considered as the adhesion surface. The rough surface treatment step 1020 may include one or more of rough machining and grit blasting of the substrate part 1100 to form the adhesion surface. Other processes and methods for roughing a surface of the substrate part 1100 in order to form pores, peaks, and valleys are of course contemplated. In select aspects, where the substrate part 1100 includes the recessed or sloped surface adjacent to the planar surface 1140, the recessed or sloped surface may also undergo the rough surface treatment step 1020.

A spraying step 1030 may be performed after the obtaining step 1010, or after the rough surface treatment step 1020. During the spraying step 1030, a spray coating material 1250 may be supplied to a top layer 1141 of the substrate part 1100, which may be a top surface or portion of the planar surface 1140. The spray coating material 1250 may be in the form of a powder or a wire feedstock. The spray coating material 1250 may be made of a Fe-based alloy, a Ni-based alloy, a Co-based alloy, a carbide-based material, and/or a ceramic material. The carbide-based materials may include tungsten and/or chromium. The ceramic materials may include Al-oxides, Co-oxides, and/or Ti-oxides. In select aspects, the spray coating material 1250 may include one or more of M2, M4, and T15 alloys. In select aspects, the spray coating material 1250 may include a depressed-eutectic alloy, which may include silicon, boron, carbon, and/or phosphorous. In select aspects, the coating material 1250 may consist of a Ni-based alloy having a chemical composition of 16-17% chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0% carbon, and a balance of nickel. In select aspects, the coating material 1250 may consist of a Fe-based alloy having a chemical composition of 0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon, 2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten, 1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to 0.03% phosphorus, up to 0.03% sulfur, and a balance of iron. In select aspects, the coating material 1250 may consist of a Co-based alloy having a composition of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20% tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, up to 1% manganese, and a balance of cobalt.

The spray coating material 1250 may be heated to a predetermined temperature and sprayed onto the top layer 1141. In select aspects, the predetermined temperature may be at or above a melting point of the spray coating material 1250. As the spray coating material 1250 is supplied to the top layer 1141 of the substrate part 1100, the spray coating material 1250 may be at least partially deposited within the pores and/or within the valleys of the top layer 1141. As the spray coating material 1250 is supplied to the top layer 1141 of the substrate part 1100, the spray coating material 1250 may solidify onto and above the top layer 1141 of the substrate part 1100 to form a thermal spray coating layer 1300, as shown in FIG. 13. In one aspect, the spraying step 1030 may be performed to form the thermal spray coating layer 1300 without or substantially without any cracks. In select aspects, the thermal spray coating layer 1300 may form a micro-porous structure, and the micro-porous structure may promote retention of lubrication during use of the finished mechanical face seal to further improve wear life. In select aspects, where the substrate part 1100 includes the recessed or sloped surface adjacent to the planar surface 1140, the spray coating material 1250 may be sprayed onto the recessed or sloped surface during the spraying step 1030. In select aspects, the spray coating material 1250 may be prevented from being applied onto the recess or sloped surface to preserve a prescribed gap distance between two opposing seal rings, when finished and assembled.

A finishing step 1040 may be performed on the substrate part 1100 to achieve final dimensions required by a particular mechanical face seal. The finishing step 1040 may be performed on any surface of the substrate part 1100. In one aspect, the finishing step 1040 may include a surface finishing process performed on the thermal spray coating layer 1300 above the planar surface 1140. The finishing step 1040 may include one or more of grinding, polishing, milling, machining, or other suitable process to finish one or more surfaces of the substrate part 1100. In select aspects, where the substrate part 1100 includes the recessed or sloped surface adjacent to the planar surface 1140, the finishing step 1040 may also be performed on the recessed or sloped surface.

Referring to FIG. 13, the substrate part 1100 may include at least an outer diameter surface 1110 and an inner diameter surface 1120 extending along a common central axis 1130. The substrate part 1100 may include the planar surface 1140 extending between the outer diameter surface 1110 and the inner diameter surface 1120. When processed and finished, the planar surface 1140 of the substrate part 1100 may form a surface of a mechanical seal ring for contact at an interface between two mechanical face seals. As discussed above with respect to the obtaining step 1010, the substrate part 1100 may be wrought or cast using an SAE 52100 alloy steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron, or grey cast iron. Other materials are contemplated as well. The substrate part 1100 may be wrought or cast to have roughly a geometry of a finished mechanical face seal. In select aspects, the obtaining step 1010 may comprise refurbishing, repairing, or salvaging a previously used or damaged substrate part in order to obtain the substrate part 1100.

During the obtaining step 1010, the substrate part 1100 may be formed into a ring-shaped element. In select aspects, the substrate part 1100 may be made of SAE 52100 alloy steel, which may have a chemical composition of 1.3% to 1.6% chromium, 0.93% to 1.1% carbon, 0.25% to 0.45% manganese, 0.15% to 0.35% silicon, up to 0.025% sulfur, up to 0.025% phosphorous, and a balance of iron. In select aspects, the substrate part 1100 may be made of SAE 1020 alloy steel, which may have a chemical composition of 0.18% to 0.23% carbon, 0.3% to 0.6% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In select aspects, the substrate part 1100 may be made of SAE 1040 alloy steel, which may have a chemical composition of 0.37% to 0.44% carbon, 0.6% to 0.9% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In select aspects, the substrate part 1100 may be made of ductile iron, which may have a chemical composition of 3.0% to 3.9% carbon, 1.7% to 2.9% silicon, 0.1% to 0.6% manganese, 0.02% to 0.06% magnesium, 0.005% to 0.04% phosphorus, up to 0.04% sulfur, up to 0.4% copper, and a balance of iron. In select aspects, the cast iron substrate may be made of grey cast iron, which may have a chemical composition of 2.5% to 4.0% carbon, 1% to 3% silicon, and a balance of iron.

In one aspect, the rough surface treatment step 1020 may be performed to provide an adhesion surface with pores, peaks, and valleys to promote bonding of the spray coating material 1250 onto the substrate part 1100. In select aspects, the rough surface treatment step 1020 may include one or more of rough machining and grit blasting of the planar surface 1140 of the substrate part 1100, which may be considered as the adhesion surface. Alternatively, the substrate part 1100 may be obtained or formed with an inherent rough surface such that the rough surface treatment step 1020 is not needed or is minimized.

The spraying step 1030 may be performed to apply the spray coating material 1250 onto the substrate part 1100, and may include one or more of a HVOF spray, TWA spray, high velocity air fuel (HVAF) spray, plasma arc spray, and kinetic/cold spray. In one aspect, the spray coating material 1250 may be heated to form molten particles prior to being sprayed and deposited onto a surface of the substrate part 1100, as discussed with respect to the spraying step 1030 described above. The molten particles may enhance the spray coating material's 1250 ability to grab onto the adhesion surface formed during the rough surface treatment step 1020.

The spraying step 1030 may include supplying and spraying the spray coating material 1250 via a sprayer 1200. In select aspects, the sprayer 1200 may include a spray head 1210 for aiming and directing the spray coating material 1250 toward a surface of the substrate part 1100, such as the planar surface 1140 of the substrate part 1100. In select aspects, the sprayer 1200 may include a heating element 1220, which may heat up the spray coating material 1250 prior to being sprayed onto the substrate part 1100. Because the substrate part 1100 itself does not need to be heated, use of the method of thermal spray coating 1000 may have a further benefit of reducing distortion of the substrate part 1100 and therefore reduced distortion of the finished mechanical seal, particularly compared with other processes that require a separate heat treatment step.

The sprayer 1200 may be attached to a robotic arm or actuator 1230, and the robotic arm or actuator 1230 may be operable to move the sprayer 1200 in a radial direction relative to the substrate part 1100. For example, during the spraying step 1030, the sprayer 1200 may be fixed at a predetermined height above the substrate part 1100, and the robotic arm or actuator 1230 may be actuated to move the sprayer 1200 back and forth above the substrate part 1100 in the radial direction between a location of the outer diameter surface 1110 and the inner diameter surface 1120 of the substrate part 1100. Additionally, while the sprayer 1200 is being actuated back and forth above the substrate part 1100, the substrate part 1100 may also be rotated about the common central axis 1130, thereby enabling the sprayer 1200 to apply an even coating of the spray coating material 1250 onto the substrate part 1100. In select aspects, the substrate part 1100 may be rotated at a rate of several hundred rotations per minute (RPM) to enable a uniform application of the spray coating material 1250 onto the planar surface 1140 of the substrate part 1100. For example, the substrate part 1100 may be rotated at a rate of between 100 RPM and 300 RPM as the spray coating material 1250 is applied onto the substrate part 1100 from the sprayer 1200.

Although one aspect of the spraying step 1030 is to apply the spray coating material 1250 onto a pre-specified adhesion surface, such as the planar surface 1140, a small amount of the spray coating material 1250 may adhere to one or more of the outer diameter surface 1110 and the inner diameter surface 1120 of the substrate part 1100. The small amount of spray or “overspray” on the outer diameter surface 1110 and/or the inner diameter surface 1120 may provide a light protective coating that can be beneficial against corrosion of the substrate part 1100. In select aspects, where the additional corrosion protection is not required or desired, the outer diameter surface 1110 and/or the inner diameter surface 1120 may be masked off prior to the spraying step 1030 to prevent any overspray from adhering onto the outer diameter surface 1110 and/or the inner diameter surface 1120. In select aspects, the overspray may be applied onto only the outer diameter surface 1110 of the substrate part 1100 for corrosion protection.

Turning to FIG. 14, once the thermal spray coating layer 1300 has been formed on the substrate part 1100, the finishing step 1040 may be performed to obtain final dimensions that correspond to a finish mechanical face seal. As shown in FIG. 14, the finishing step 1040 may comprise a surface finishing process which may include one or more of grinding, polishing, milling, machining, or other suitable process to remove material 1410 from a top surface 1305 of the thermal spray coating layer 1300 to obtain final dimensions of a finished mechanical face seal. The finishing step 1040 may remove material between 100 microns and 200 microns in depth from the thermal spray coating layer 1300 formed during spraying step 1030.

In select aspects, the thermal spray coating layer 1300 may be finished to a thermal spray coating layer thickness of between 0.1 mm and 2.0 mm. In select aspects, the thermal spray coating layer thickness may be approximately 0.7 mm, when selecting a relatively more wear resistant material from the list of spray coating materials 1250 discussed above, and approximately 1.2 mm when selecting a relatively less wear resistant material. In select aspects, the top surface 1305 of the thermal spray coating layer 1300 is free of cracks and may include micro pores with depths greater than those formed during the laser cladding process. In select aspects, the micro pores may define valleys with depths between 0.25 microns and 1.0 microns. These large valleys may advantageously hold pockets of lubricant during operation and enhance cooling of sliding surfaces of the mechanical seal.

INDUSTRIAL APPLICABILITY

The disclosure is applicable to bearing surfaces, and in particular mechanical face seals. Various aspects of the disclosure provide a cost-effective substrate part that may be laser cladded and/or thermally spray coated to achieve superior strength and resistance against harsh environments. The substrate part 400 may be laser cladded and finished to form mechanical face seals, as shown in FIGS. 7-10, or the substrate part 1100 may be provided with the thermal spray coating 1000 to form the mechanical face seals, as shown in FIGS. 12-14. These mechanical face seals may be used in heavy duty rotating applications, such as axles, gearboxes, tracked vehicles, conveyer systems, etc. As shown in FIGS. 3 and 4, the mechanical face seals, when installed in a rotating application, may include two identical metal seal rings 110, 112, 210, 212 that are mounted face-to-face with one another in two separate housings or retainers. One of the two metal seal rings 112, 210 remains static in its respective retainer 102, 202, while the other of the two metal seal rings 110, 212 rotates with its counter face rotating retainer 104, 204.

With reference to the method of laser cladding 300, the substrate part 400 may be provided or formed in the obtaining step 310. As shown in FIG. 7, the substrate part 400 may be wrought or cast out of SAE 52100 steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron, or grey cast iron. In select aspects, the substrate part 400 may be made of SAE 52100 alloy steel, the SAE 52100 alloy steel having a chemical composition of 1.3% to 1.6% chromium, 0.93% to 1.1% carbon, 0.25% to 0.45% manganese, 0.15% to 0.35% silicon, up to 0.025% sulfur, up to 0.025% phosphorous, and a balance of iron. In select aspects, the substrate part 400 may be made of SAE 1020 alloy steel, which may have a chemical composition of 0.18% to 0.23% carbon, 0.3% to 0.6% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In select aspects, the substrate part 400 may be made of SAE 1040 alloy steel, which may have a chemical composition of 0.37% to 0.44% carbon, 0.6% to 0.9% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In select aspects, the substrate part 400 may be made of ductile iron, which may have a chemical composition of 3.0% to 3.9% carbon, 1.7% to 2.9% silicon, 0.1% to 0.6% manganese, 0.02% to 0.06% magnesium, 0.005% to 0.04% phosphorus, up to 0.04% sulfur, up to 0.4% copper, and a balance of iron. In select aspects, the cast iron substrate may be made of grey cast iron, the grey cast iron having a chemical composition of 2.5% to 4.0% carbon, 1% to 3% silicon, and a balance of iron.

During the supplying step 340, the coating material 950 supplied to the top layer 441 of the substrate part 400 may be made of Fe-based alloys, Ni-based alloys, or Co-based alloys. In select aspects, the coating material 950 may include Durmat® 60A, M2 tool steel, Stellite® 1, Stellite® 6, or other suitable material. In select aspects, the coating material 950 may consist of a Ni-based alloy having a chemical composition of 16-17% chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0% carbon, and a balance of nickel. In select aspects, the coating material 950 may consist of a Fe-based alloy having a chemical composition of 0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon, 2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten, 1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to 0.03% phosphorus, up to 0.03% sulfur, and a balance of iron. In select aspects, the coating material 950 may consist of a Co-based alloy having a composition of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20% tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, up to 1% manganese, and a balance of cobalt.

The substrate part 400 may be preheated in the preheating step 320. The substrate part 400 may be exposed to the laser 800 during the exposing step 330, and coating material 950 may be supplied to the top layer 441 of the substrate part 400 to form the intermediate layer 500 and/or the cladding layer 600, as shown in FIG. 8. The finishing step 350 may be performed to finish the top surface 605 of the cladding layer 600, the outer diameter surface 410 of the substrate part 400, and/or the inner diameter surface 420 of the substrate part 400 during a surface finishing process, as shown in FIGS. 9 and 10. The finishing step 350 may include a heat treatment process where the substrate part 400 is compressed in a thermally controlled environment to relieve product stresses. In select aspects, the top surface 605 of the cladding layer 600 is free of cracks. Once finished, the substrate part 400 forms a completed mechanical face seal, which may be used in rotating applications such as axles, gearboxes, tracked vehicles, conveyer systems, etc. The low cost substrate part 400 in addition to the cladding layer 600 enables mechanical faces seals to be produced in a more cost effective manner while still providing the necessary strength and durability to withstand harsh environmental operating conditions.

With reference to the method of thermal spray coating 1000, the substrate part 1100 may be provided or formed in the obtaining step 1010. As shown in FIG. 12, the substrate part 1100 may be wrought or cast out of SAE 52100 alloy steel, which may have a chemical composition of 1.3% to 1.6% chromium, 0.93% to 1.1% carbon, 0.25% to 0.45% manganese, 0.15% to 0.35% silicon, up to 0.025% sulfur, up to 0.025% phosphorous, and a balance of iron. In select aspects, the substrate part 1100 may be made of SAE 1020 alloy steel, which may have a chemical composition of 0.18% to 0.23% carbon, 0.3% to 0.6% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In select aspects, the substrate part 1100 may be made of SAE 1040 alloy steel, which may have a chemical composition of 0.37% to 0.44% carbon, 0.6% to 0.9% manganese, up to 0.04% phosphorus, up to 0.05% sulfur, and a balance of iron. In select aspects, the substrate part 1100 may be made of ductile iron, which may have a chemical composition of 3.0% to 3.9% carbon, 1.7% to 2.9% silicon, 0.1% to 0.6% manganese, 0.02% to 0.06% magnesium, 0.005% to 0.04% phosphorus, up to 0.04% sulfur, up to 0.4% copper, and a balance of iron. In select aspects, the cast iron substrate may be made of grey cast iron, which may have a chemical composition of 2.5% to 4.0% carbon, 1% to 3% silicon, and a balance of iron.

The spray coating material 1250 to be applied to the substrate part 1100 may be in the form of a powder or a wire feedstock. The spray coating material 1250 may be made of Fe-based alloys, Ni-based alloys, Co-based alloys, carbide-based materials, and/or ceramic materials. The carbide-based materials may include tungsten and/or chromium. The ceramic materials may include Al-oxides, Co-oxides, and/or Ti-oxides. In select aspects, the spray coating material 1250 may include one or more of M2, M4, and T15 alloys. In select aspects, the spray coating material 1250 may include a depressed-eutectic alloy, which may include silicon, boron, carbon, and/or phosphorous. In select aspects, the coating material 1250 may consist of a Ni-based alloy having a chemical composition of 16-17% chromium, 3.3% boron, 3.8% silicon, 0.8% to 1.0% carbon, and a balance of nickel. In select aspects, the coating material 1250 may consist of a Fe-based alloy having a chemical composition of 0.78% to 1.05% carbon, 0.15% to 0.40% manganese, 0.20% to 0.45% silicon, 2.0% to 4.5% chromium, 4.5% to 5.5% molybdenum, 5.5% to 6.75% tungsten, 1.75% to 2.20% vanadium, up to 0.3% nickel, up to 0.25% copper, up to 0.03% phosphorus, up to 0.03% sulfur, and a balance of iron. In select aspects, the coating material 1250 may consist of a Co-based alloy having a composition of 26.5% to 33% chromium, 0.8% to 2.7% carbon, 3.5% to 20% tungsten, 0.8% to 1.2% silicon, up to 3% iron, up to 1.5% molybdenum, up to 1% manganese, and a balance of cobalt.

During the rough surface treatment step 1020, the planar surface 1140 of the substrate part 1100 may be treated to form pores, peaks, and valleys on the planar surface 1140. The rough surface treatment step 1020 may include one or more of rough machining and grit blasting of the substrate part 1100, which may include rough machining and/or grit blasting of the planar surface 1140. In select aspects, the substrate part 1100 may include a recessed or sloped surface adjacent to the planar surface 1140, which may be used to form a seal ring to be used in a spring-loaded metal face seal arrangement. The recessed or sloped surface adjacent to the planar surface 1140 may also undergo the rough surface treatment step 1020.

During the spraying step 1030, the spray coating material 1250 may be sprayed onto the substrate part 1100 via the sprayer 1200, as shown in FIG. 12. The sprayer 1200 may include the spray head 1210 for aiming and directing the spray coating material 1250 onto a surface of the substrate part 1100, such as the planar surface 1140. In select aspects, where the substrate part 1100 includes the recessed or sloped surface adjacent to the planar surface 1140, the spray coating material 1250 may be sprayed onto the recessed or sloped surface during the spraying step 1030. In select aspects, the spray coating material 1250 may be prevented from being applied onto the recess or sloped surface to preserve a prescribed gap distance between two opposing seal rings, when finished and assembled.

In select aspects, the sprayer 1200 may be attached to a robotic arm or actuator 1230, and the sprayer 1200 may be actuated in the radial direction, relative to the substrate part 1100, in order to reach and provide coverage of the spray coating material 1250 across an entire surface of the substrate part 1100, such as the planar surface 1140. Additionally, or alternatively, the substrate part 1100 may be rotated about the common central axis 1130 in order to enable a uniform application of the spray coating material 1250 onto the planar surface 1140 of the substrate part 1100. In select aspects, the substrate part 1100 may be rotated at a rate of between 100 RPM and 300 RPM as the spray coating material 1250 is sprayed onto the substrate part 1100 from the sprayer 1200, and the sprayer 1200 may be actuated to move back and forth above the substrate part 1100 in the radial direction between a location of the outer diameter surface 1110 and the inner diameter surface 1120 of the substrate part 1100.

The sprayer 1200 may include the heating element 1220, which may be used to heat the spray coating material 1250 to form molten particles prior to being sprayed and deposited onto a surface of the substrate part 1100. These molten particles may enhance the spray coating material's 1250 ability to grab onto the adhesion surface formed during the rough surface treatment step 1020. A thickness of between 0.1 mm and 2.0 mm of the spray coating material 1250 may be deposited or applied to the substrate part 1100 to form the thermal spray coating layer 1300 above the planar surface 1140, as shown in FIG. 13. The thermal spray coating layer 1300 may define micro pores with depths of between 0.25 microns and 1.0 microns that may advantageously hold pockets of lubricant during operation and enhance cooling of sliding surfaces of the mechanical seal during use.

During the finishing step 1040, a surface finishing process may be performed on the thermal spray coating layer 1300 above the planar surface 1140, as shown in FIG. 14. The finishing step 1040 may include one or more of grinding, polishing, milling, machining, or other suitable process to finish one or more surfaces of the substrate part 1100. In select aspects, a depth of between 100 microns and 200 microns of material may be removed from the thermal spray coating layer 1300. In select aspects, where the substrate part 1100 includes the recessed or sloped surface adjacent to the planar surface 1140, the finishing step 1040 may also be performed on the recessed or sloped surface.

Once finished, the substrate part 1100 forms a completed mechanical face seal, which may be used in rotating applications such as axles, gearboxes, tracked vehicles, conveyer systems, etc. The low cost substrate part 1100 in addition to the thermal spray coating layer 1300 enable mechanical faces seals to be produced in a more time and cost effective manner while still providing the necessary strength and durability to withstand harsh environmental operating conditions. In particular, the method of thermal spray coating 1000 may require less coating material to be applied to the substrate part 1100, compared with other methods in the related art, thereby reducing the overall material cost and the amount of time required for the application of the spray coating material 1250 onto the substrate part 1100. Furthermore, since less material may be applied onto the substrate part 1100, a reduction in time required to obtain final dimensions during the finishing step 1040 may also be achieved.

It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated.

Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

	Number	Date	Country
Parent	14482475	Sep 2014	US
Child	14937319		US

Thermal Spray Coating for Mechanical Face Seals

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CROSS-REFERENCE TO RELATED APPLICATION

Continuation in Parts (1)