Patent Application
20160067825
The disclosure relates generally to the field of mechanical components formed by a laser cladding process and, more particularly, to a mechanical seal formed by a laser cladding process.
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.
In one aspect, the present disclosure describes a method of producing a tightly dimensionally controlled mechanical face seal. The method may include 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 supplying a coating material to a top layer of the planar surface. The method may include exposing a laser to at least the planar surface, and the exposing may include tracing the top layer of the planar surface to melt a top surface of the substrate part and the coating material together to form a metallurgical bond.
In another aspect, the present disclosure describes a method of producing a tightly dimensionally controlled 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 exposing a laser to at least one portion of the planar surface to preheat the substrate part. The method may include supplying a coating material to the planar surface that has been preheated. The method may further include exposing the laser to at least one portion of the planar surface that has been preheated to melt a top surface of the substrate part and the coating material together to form a metallurgical bond.
In yet another aspect, the present disclosure describes a method of producing a tightly dimensionally controlled mechanical face seal, including forming a cast or wrought substrate part made of SAE 52100 alloy steel, SAE 1020 alloy steel, SAE 1040 alloy steel, ductile iron, or grey cast iron. 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 exposing a laser to at least one portion of the planar surface to preheat the substrate part. The method may include supplying a coating material comprising a Fe-based alloy, a Ni-based alloy, or a Co-based alloy to the planar surface that has been preheated and further exposing the laser to the at least one portion of the planar surface that has been preheated to melt a top surface of the substrate part and the coating material together to form a metallurgical bond. The supplying and further exposing may form an intermediate layer by melting the coating material and a material of the substrate part together, and may form a cladding layer of the coating material above the intermediate layer. 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 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.
Now referring to the drawings,
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 tire 13 of the machine 10. As shown in
It should be noted that the machine 10 shown in
Referring to
Turning to
Turning to
The rotating seal ring 110 and the static seal ring 112 together form a first mechanical face seal 120 and 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 is applied at the interface 106 of the first mechanical face seal 120 and at the interface 206 of the second mechanical face seal 220. 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.
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 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, these methods have led to coatings that lacked durability, delaminated from the substrate, lead to unacceptable surface cracking or similar failure.
Referring to
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 1000 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 laser 1000 is exposed to the surface of the substrate part 400, either for the first time, or a subsequent time if a preheating step 320 is performed by the laser 1000. During the exposing step 330, the laser 1000 may trace along the top layer 441 of the substrate part 400, at least partially melting 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 1150 is supplied to the top layer 441 of the substrate part 400 at or near a location of the laser 1000 being traced on the planar surface 440, whereby the top layer 441 of the substrate part 400 is melted together with the coating material 1150 via the laser 1000 to form an intermediate layer 500. The intermediate layer 500 may include both the coating material 1150 and a material of the substrate part 400, as shown in
A finishing step 350 may be performed on the substrate part 400. 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 of 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 of 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
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 1000. In select aspects, the laser 1000 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 1000 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 1000.
Concurrently with or just after the exposing step 330, as the laser 1000 traces over at least one portion 442 of the top layer 441, the supplying step 340 may be performed to supply the coating material 1150 to the portion 442 of the planar surface 440 at or near a location of the laser 1000 traced on the planar surface 440. The supplied coating material 1150 may be fed through a supplier 1100, which is positioned to deliver the coating material 1150 at or near the portion 442 of the planar surface 440 being traced by the laser 1000. In select aspects, the supplier 1100 may be attached to a laser generator 1050 that generates the laser 1000. In select aspects, the supplier 1100 may be integral with the laser generator 1050, as shown in
The coating material 1150 may be in the form of a wire or a powder, and the coating material 1150 may be made of Fe-based alloys, Ni-based alloys, and/or Co-based alloys. In select aspects, the coating material 1150 may include Durmat® 60A, M2 tool steel, Stellite® 1, Stellite® 6, or other suitable material. In select aspects where the coating material 1150 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 1150 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 1150 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 1150 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 1100 may be configured to feed a spool of the wire of the coating material 1150 or to spray a stream of powder of the coating material 1150 to the portion 442 of the planar surface 440. As the coating material 1150 is supplied to the portion 442 of the planar surface 440, during the supplying step 340, heat from the laser 1000 and/or the melted top layer 441 of the planar surface 440 may cause the coating material 1150 to melt and mix with the top layer 441 of the planar surface 440, thereby forming an intermediate layer 500, as shown in
The supplying step 340 may further supply coating material 1150 to be melted by the laser 1000 and/or heat from the intermediate layer 500 to form a cladding layer 600 disposed above the intermediate layer 500, as shown in
Turning to
As shown in
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 to achieve superior strength and resistance against harsh environments. As shown in
In one aspect of the disclosure, the substrate part 400 may be provided in the obtaining step 310. As shown in
In one aspect of the disclosure, the coating material 1150 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 1150 may include Durmat® 60A, M2 tool steel, Stellite® 1, Stellite® 6, or other suitable material. In select aspects, the coating material 1150 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 1150 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 1150 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.
In one aspect of the disclosure, the substrate part 400 may be preheated in the preheating step 320. The substrate part 400 may be exposed to the laser 1000 during the exposing step 330, and coating material 1150 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. 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. 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.
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.
