Patent Application
20130277348
The subject matter disclosed herein relates to welding and, more particularly, repair welding for high temperature performance alloys.
Metal and alloy parts may experience various wear instances or patterns in material as a result of application fatigue such as cracking, wearing, abrasions, erosion or any other act that may cause the removal or wear of substrate material. To replace the loss in material and repair the part, various forms of welding can be used to bond new weld material to the original substrate material. Such welding can include heating the substrate material (i.e., the part being repaired), contacting the weld material to the substrate material, and then applying additional heat or energy to the weld material so that the weld material melts to become liquidus and can thereby bond with the substrate material. However, some materials, such as nickel based superalloys that can be used in high temperature applications such as in hot gas path components in gas turbines (e.g., buckets), can crack and/or be less susceptible to forming strong bonds with weld material if welded while at a non-elevated temperature, such as at room temperature, and/or using non-matching weld material.
Welds may therefore be performed by preheating substrate materials to an elevated temperature prior to welding. However, the constant additional heat or energy used during welding to actually melt the weld material can also radiate to the substrate material and cause an even further increase in the substrate material's temperature such as to a point above its solidus or liquidus. Such an increase may then result in slumping, melting or other changes to the microstructure that can reduce the substrate material's physical properties such as strength and/or toughness.
Accordingly, alternative welding methods and apparatuses would be desirable in the art.
In one embodiment, a preheated interval welding method for welding a weld material to a substrate material is disclosed. The preheated interval welding method includes preheating the substrate material to a preheat temperature less than a solidus temperature of the substrate material, melting the weld material to produce molten weld material at a melting distance away from the substrate material, and applying the molten weld material in a plurality of intervals to the substrate material.
In another embodiment, another preheated interval welding method for welding a weld material to a substrate material is disclosed. The preheated interval welding method includes disposing a welding apparatus adjacent a substrate material, preheating the substrate material to a preheat temperature less than its solidus temperature, and transitioning the welding apparatus element away from the substrate material and adjacent to the weld material. The method further includes melting the weld material to produce molten weld material and applying the molten weld material in a plurality of intervals to the substrate material.
In yet another embodiment, a preheated interval welding system for preheating a substrate material and applying a weld material is disclosed. The preheated interval welding system includes a preheating apparatus that preheats a repair surface of the substrate material to a preheat temperature and a welding apparatus that melts the weld material into molten weld material and applies the molten weld material to the repair surface in a plurality of intervals.
These and additional features provided by the embodiments discussed herein will be more fully understood in view of the following detailed description, in conjunction with the drawings.
The embodiments set forth in the drawings are illustrative and exemplary in nature and not intended to limit the inventions defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:
Preheated interval welding methods disclosed herein generally comprise first preheating a substrate material to a preheat temperature approaching its solidus temperature. Weld material is then melted and applied to the substrate material in a plurality of intervals. The interval-regimented application of weld material to the preheated substrate material can allow for the reduction in temperature differential between the two materials while further controlling the amount of excess heat applied to the substrate material around the weld.
With reference to
As illustrated in
The substrate material 110 may comprise any dimensions and geometry that allow for a weld location to be preheated and then allow for the application of weld material 120. For example, in some embodiments, such as that illustrated in
The exemplary preheated interval welding system 100 further comprises a weld material 120 that is to be welded onto the substrate material 110. The weld material 120 can comprise any material that can be heated to a state above its liquidus temperature such that it melts and can be applied to the substrate material 110 in a plurality of intervals as will become appreciated herein. In some embodiments, the weld material 120 can comprise the same or similar material as the substrate material 110. Such embodiments may allow for less shrinkage, cracking or other performance defects by having the substrate material 110 and the weld material 120 possess the same or similar physical characteristics. Such an embodiment can provide a closer match of physical properties between the substrate material 110 and the weld material 120 to potentially allow for increased and more predictable performance.
Similar to the substrate material 110, the weld material 120 may comprise any dimensions and geometry that allow for the weld material 120 to be heated to a temperature greater than its liquidus temperature such that molten weld material 121 can be applied in a plurality of intervals to the substrate material 110. For example, in some embodiments, such as that illustrated in
Still referring to
In some embodiments, such as that illustrated in
Referring now to
Preheating the substrate material 110 in step 10 comprises heating the area of the substrate material 110 where the weld material 120 is to be added (e.g., a void 112 in the repair surface 111 of the substrate material 110) to a preheat temperature. The preheat temperature can comprise any temperature above room temperature such as a temperature that approaches the solidus temperature of the substrate material 110.
The substrate material 110 can be preheated using any available preheating apparatus 140 that is capable of heating an area of the substrate material 110 to the preheat temperature. As discussed above, in some embodiments (e.g., the embodiment illustrated in
Heat/energy may then be applied in step 12 to the substrate material 110. For example, where the welding apparatus 130 comprises an induction welding apparatus, the electrical current from the power supply 131 can be initiated such that the electromagnetic field from the induction coil 132 creates resistive heating from the electromagnetic induction. The power supply 131 can be monitored and adjusted to heat the substrate material 110 to the preheat temperature such as one that approaches but does not exceed the substrate material's 110 solidus temperature.
In some embodiments, the temperature of the substrate material 110 may be monitored via one or more temperature sensors such as thermocouples, pyrometers thermometers and/or any other appropriate device. Feedback from the one or more temperature sensors can be utilized to control the amount of heat and/or energy applied to the substrate material 110 such that its elevated preheat temperature is controlled. For example, such feedback can be utilized to control the amount of power to the welding apparatus 130 (or other preheating apparatus 140), the distance between the substrate material 110 and the welding apparatus 130, or any other variable that may affect the temperature of the substrate material 110.
Preheating the substrate material 110 in step 10 may optionally further comprise transitioning the preheating apparatus 140 away from the substrate material 110 in step 13 to stop or limit the amount of heat applied to the substrate material 110. For example, where the preheating apparatus 140 would obstruct the application of the weld material 120, and/or where the continuous presence of the preheating apparatus 140 would cause a continuous rise in temperature of the substrate material 110, then the preheating apparatus 140 may be transitioned away from the substrate material 110 to better allow for the subsequent application of molten weld material 121 and/or limit the amount of preheating of the substrate material 110. Alternatively, where the physical presence of the preheating apparatus 140 does not interfere with the subsequent application of molten weld material 121 and the preheat temperature can still be controlled with its continuous presence, the preheating apparatus 140 may optionally remain adjacent the substrate material 110 throughout welding to maintain the substrate material 110 at or around the preheat temperature.
Referring to
Melting the weld material 120 in step 20 may be accomplished utilizing a variety of welding apparatuses 130 as discussed above by applying heat and/or energy to the weld material 120 in step 22 to produce molten weld material 121. For example, as illustrated in
Furthermore, melting the weld material 120 in step 20 may be performed in any type of environment. For example, in some embodiments, the melting of the weld material 120 in step 20 may occur in an inert atmosphere. In some embodiments, the melting of the weld material 120 in step 20 may occur in a low pressure environment. In some embodiments, the melting of the weld material 120 in step 20 may occur in any other type of environment that allows for the melting of the weld material 120 to produce molten weld material 121 for the subsequent application to the substrate material 110 in a plurality of intervals.
In some embodiments, such as where the preheating apparatus 140 and the welding apparatus 130 comprise the same apparatus (e.g., as illustrated in
Still referring to
In some embodiments, each application of molten weld material 121 (e.g., steps 31, 33 and 35) may comprise substantially similar amounts of molten weld material 121 such that each application adds a more predictable amount of molten weld material 121 to the substrate material 110. Additionally, where melting the weld material 120 in step 20 occurs in a specific environment (e.g., low pressure, in the presence of inert gasses, etc.), the application of molten weld material 121 in a plurality of intervals to the substrate material 110 in step 30 may similarly occur in the same or substantially similar environment.
It should now be appreciated that by preheating the substrate material 110 to a preheat temperature approaching its liquidus temperature, the substrate material 110 can provide for an eventual metallurgical bond with the weld material 120 with more similar microstructural and physical properties, particularly when the weld material 120 matches the substrate material 110. Moreover, the preheated substrate material 110 can also be preheated to a temperature approaching its solidus temperature such that when the molten weld material 121 is applied to the substrate material 110 (e.g., when a drop of the molten weld material 121 touches the substrate material 110), a small layer of the substrate material 110 may briefly rise to or above its solidus temperature where it is contact with the molten weld material 121. Such an application may both provide a strong bond between the substrate material 110 and the weld material 120 while also reducing the heat affected zone (“HAZ”) by limiting the amount of heat/energy applied to the substrate material 110.
The terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context, (e.g., includes the degree of error associated with measurement of the particular quantity). The suffix “(s)” as used herein is intended to include both the singular and the plural of the term that it modifies, thereby including one or more of that term (e.g., the metal(s) includes one or more metals).
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
