A WELDED COMPONENT  A WELDED GAS TURBINE COMPONENT  AND A PROCESS OF WELDING A COMPONENT
FIELD OF THE INVENTION
[0001] The present invention is directed to manufactured components and processes of forming manufactured components. More specifically  the present invention relates welded components and processes of welding components.
BACKGROUND OF THE INVENTION
[0002] The operating temperature within a gas turbine is both thermally and chemically hostile. Significant advances in high temperature capabilities have been achieved through the development of iron  nickel  and cobalt-based superalloys and the use of environmental coatings capable of protecting superalloys from oxidation  hot corrosion  etc. Parts can be fabricated by joining subcomponents including the superalloys. It is desirable to improve weldability based upon liquation and strain age cracking. Improving the weldability can extend the usable life of the parts.
[0003] In the compressor portion of a gas turbine  atmospheric air is compressed to 10-25 times atmospheric pressure  and adiabatically heated to 700° F - 1250° F (371° C - 677° C) in the process. This heated and compressed air is directed into a combustor  where it is mixed with fuel. The fuel is ignited  and the combustion process heats the gases to very high temperatures  in excess of 3000° F (1650° C). These hot gases pass through the turbine  where airfoils fixed to rotating turbine disks extract energy to drive an attached generator which produces electrical power. To improve the efficiency of operation of the turbine  combustion temperatures have been raised. Of course  as the combustion temperature is raised  steps must be taken to prevent thermal degradation of the materials forming the flow path for these hot gases of combustion.
[0004] Certain known alloys may be used for components disposed along the flow path of these hot gases. Certain portions of these components must be able to withstand temperatures higher than other portions of these components. For example  certain portions may be resistant to temperatures for adiabatically heated (for example  800° F - 1250° F) and other portions may be further resistant to hot gases heated by the combustion processes (for example  in excess of 3000° F). Components made entirely of alloys resistant to the highest temperature may be undesirable by being overly expensive or by failing to include other properties desirable in other portions of the components. Alternatively  components made entirely of alloys resistant only to the temperature of the lower temperature portions may fail.
[0005] A welded component  a welded gas turbine component  and a process of welding a component that do not suffer from one or more of the above drawbacks would be desirable in the art.
BRIEF DESCRIPTION OF THE INVENTION
[0006] According to an exemplary embodiment  a welded component includes a first alloy subcomponent  a second alloy subcomponent  and a weld between the first alloy subcomponent and the second alloy subcomponent. The weld includes a gradient having a transition region.
[0007] According to another exemplary embodiment  a welded gas turbine component includes a first alloy  a second alloy  and a weld positioned between the first alloy and the second alloy. The weld is formed by a first shim and a second shim being beam welded.
[0008] According to another exemplary embodiment  a process of welding a component includes positioning a first alloy  positioning a second alloy  positioning a first shim and a second shim between the first alloy and the second alloy  and beam welding the first shim and the second shim to form a weld between the first alloy and the second alloy.
[0009] Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment  taken in conjunction with the accompanying drawings which illustrate  by way of example  the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 shows a perspective view of a component being welded.
[0011] FIG. 2 shows a schematic side view of a component having a joint gap between a first portion and a second portion.
[0012] FIG. 3 shows a schematic side view of a component having two shims inserted between a first portion and a second portion of the component.
[0013] FIG. 4 shows a schematic side view of a component having a weld formed by beam welding of two shims inserted between a first portion and a second portion of the component.
[0014] FIG. 5 shows a schematic side view of two shims positioned within a component and welded within the component.
[0015] FIG. 6 shows a schematic side view of three shims positioned within a component and welded within the component.
[0016] FIG. 7 shows a schematic side view of two shims positioned within a component and welded within the component.
[0017] FIG. 8 shows a schematic side view of three shims positioned within a component and welded within the component.
[0018] Wherever possible  the same reference numbers will be used throughout the drawings to represent the same parts.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Provided is a welded component  a welded gas turbine component (for example  a gas turbine shroud  a gas turbine blade  or a gas turbine nozzle)  and a process of welding a component. Embodiments of the present disclosure have increased fusion weldability  have decreased liquation tendency  have decreased strain age cracking tendency  permit use of portions having otherwise incompatible properties  have increased stress resistance  have increased ductility  and combinations thereof.
[0020] Referring to FIG. 1  a component 100 includes a first portion 102 or subcomponent having a first alloy 104 and a second portion 106 or subcomponent having a second alloy 108. The first portion 102 and the second portion 106 are welded together by using two or more shims 111 forming a weld 110. The weld 110 is formed by a first shim 112 positioned proximal to the first portion 102 and a second shim 114 positioned between the first shim 112 and the second portion 106. The weld 110 is beam welded  for example  by an energy beam 118  such as an electron beam or laser beam. In further embodiments  a third shim 602 or more shims also form the weld 110 (see FIGS. 6 and 8). The shims 111 form a gradient composition within a joint gap 202 (see FIG. 2) positioned between the first portion 102 and the second portion 106  thereby improving the weldability and joint properties of the weld 110.
[0021] FIGS. 2-4 schematically show the first portion 102 and the second portion 106 at various stages of an exemplary process of forming the component 100. FIG. 2 shows a side view of the component 100 with the first portion 102 and the second portion 106 being separate and being arranged to form the joint gap 202. In this embodiment  the joint gap 202 completely separates the first portion 102 and the second portion 106. In another embodiment  the first portion 102 and the second portion 106 are partially attached and the joint gap 202 extends between the first portion 102 and the second portion 106. Referring to FIG. 3  according to an embodiment of the process  upon the first portion 102 and the second portion 106 being positioned  the first shim 112 and the second shim 114 are positioned within the joint gap 202 between the first alloy 102 and the second alloy 106. The shims 111 are beam welded (for example  electron beam or laser welded) to form the weld 110 shown in FIG. 4.
[0022] The first alloy 104 in the first portion 102 of the component 100 differs in composition from the second alloy 108 in the second portion 106 of the component 100. In one embodiment  the first alloy 104 and the second alloy 108 are any suitable superalloys.
[0023] In one embodiment  the first alloy 104 or the second alloy 108 includes a nickel-based alloy having  by weight  up to about 15% chromium  up to about 10% cobalt  up to about 4% tungsten  up to about 2% molybdenum  up to about 5% titanium  up to about 3% aluminum  and up to about 3% tantalum. In a further embodiment  the first alloy 104 or the second alloy 108 has a composition  by weight  of about 14% chromium  about 9.5% cobalt  about 3.8% tungsten  about 1.5% molybdenum  about 4.9% titanium  about 3% aluminum  about 0.1% carbon  about 0.01% boron  about 2.8% tantalum  and a balance of nickel.
[0024] In one embodiment  the first alloy 104 or the second alloy 108 includes a nickel-based alloy having  by weight  up to about 10% chromium  up to about 8% cobalt  up to about 4% titanium  up to about 5% aluminum  up to about 6% tungsten  and up to about 5% tantalum. In a further embodiment  the first alloy 104 or the second alloy 108 has a composition  by weight  of about 9.8% chromium  about 7.5% cobalt  about 3.5% titanium  about 4.2% aluminum  about 6% tungsten  about 1.5% molybdenum  about 4.8% tantalum  about 0.09% carbon  about 0.009% boron  and a balance of nickel.
[0025] In one embodiment  the first alloy 104 or the second alloy 108 includes a nickel-based alloy having  by weight  up to about 8% cobalt  up to about 7% chromium  up to about 6% tantalum  up to about 7% aluminum  up to about 5% tungsten  up to about 3% rhenium  and up to about 2% molybdenum. In a further embodiment  the first alloy 104 or the second alloy 108 has a composition  by weight  of about 8% cobalt  about 7% chromium  about 6% tantalum  about 6.2% aluminum  about 5% tungsten  about 3% rhenium  about 2% molybdenum  about 0.2% hafnium and a balance of nickel.
[0026] In one embodiment  the first alloy 104 or the second alloy 108 includes a nickel-based alloy having  by weight  up to about 10% chromium  up to about 8% cobalt  up to about 5% aluminum  up to about 4% titanium  up to about 2% molybdenum  up to about 6% tungsten  and up to about 5% tantalum. In a further embodiment  the first alloy 104 or the second alloy 108 has a composition  by weight  of about 10% chromium  about 8% cobalt  about 4.2% aluminum  about 3.5% titanium  about 2% molybdenum  about 6% tungsten  about 5% tantalum  about 0.5% niobium  about 0.2% hafnium  and a balance of nickel.
[0027] In one embodiment  the first alloy 104 or the second alloy 108 includes a nickel-based alloy having  by weight  up to about 10% cobalt  up to about 8% chromium  up to about 10% tungsten  up to about 6% aluminum  up to about 3% tantalum  and up to about 2% hafnium. In a further embodiment  the first alloy 104 or the second alloy 108 has a composition  by weight  of about 9.5% cobalt  about 8% chromium  about 9.5% tungsten  about 0.5% molybdenum  about 5.5% aluminum  about 0.8% titanium  about 3.0% tantalum  about 0.01 zirconium  about 0.10 carbon  about 1.5% hafnium and a balance of nickel.
[0028] In one embodiment  the first alloy 104  the second alloy 108  or the first alloy 104 and the second alloy 108 are alloys capable of withstanding predetermined temperatures (for example  temperatures of a gas turbine hot gas path). For example  in one embodiment  the first alloy 102 is resistant to heat above a first/higher temperature (for example  about 1000° F  about 1250° F  about 1500° F  about 2000° F  or about 3000° F) and the second alloy 108 is resistant to heat above a second/lower temperature (for example  between 800° F and 1250° F  about 800° F  about 1000° F  about 1250° F  about 1500° F  or about 2000° F). In one embodiment  the first temperature is substantially higher than the second temperature. In a further embodiment  the second alloy 108 is not resistant to the first/higher temperature. Additionally or alternatively  in one embodiment  the first alloy 104  the second alloy 108 or the first alloy 104 and the second alloy 108 include single crystal grains  directionally-solidified grains  or equiaxed grains.
[0029] Referring to FIGS. 2-4  upon being welded  the shims 111 have a modified microstructure within the joint gap 202  thereby modifying the properties of the weld 110. The shims 111 are thin bands of material positionable within the joint gap 202. In one embodiment  one or more of the shims 111 are flexible and capable of being stored as a roll prior to use. In one embodiment  one or more of the shims 111 are a predetermined length (for example  a length corresponding to a length of a surface on the first portion 102 or the second portion 106)  a predetermined height 304 (for example  a height corresponding to a height of the first portion 102 and/or the second portion 106)  a predetermined thickness 306 (for example  as described below with reference to FIGS. 5-8)  or combinations thereof. In one embodiment  the shims 111 vary in thickness along the length of the shims 111. In this embodiment  thicker portions of the shims 111 correspond to regions of the joint gap 202 benefiting from greater amounts of material and thinner portions of the shims 111 correspond to regions of the joint gap 202 benefiting from the presence of lower amounts of material.
[0030] Referring to FIG. 5  in one embodiment  the first shim 112 and the second shim 114 have substantially identical thicknesses 306 (for example  about 0.02 inches each  about 0.01 inches each  or between about 0.01 inches and about 0.03 inches each). Upon receiving the energy from the energy beam 118  the first shim 112 and the second shim 114 form the weld 110 having a gradient 502 including a first region 504 of a first shim material 506  a second region 508 of a second shim material 510  a shim transition region 512 (for example  a fusion zone) between the first shim material 506 and the second shim material 510  a first shim-alloy transition region 514 (for example  a first heat affected zone) between the first shim material 506 and the first alloy 104  and a second shim-alloy transition region 516 (for example  a second heat affected zone) between the second shim material 510 and the second alloy 108. In this embodiment  the first region 504 and the second region 508 have substantially identical thicknesses 306.
[0031] Referring to FIG. 6  in one embodiment  the first shim 112  the second shim 114  and a third shim 602 (for example  a middle shim) have substantially identical thicknesses 306 (for example  about 0.02 inches each  about 0.01 inches each  or between about 0.01 inches and about 0.03 inches each). Upon receiving the energy from the energy beam 118  the first shim 112  the second shim 114  and the third shim 602 form the weld 110 having the gradient 502 including the first region 504 of the first shim material 506  the second region 508 of the second shim material 510  a third region 601 of a third shim material 603  a first shim-shim transition zone 604 (for example  a first fusion zone) between the first shim material 506 and the third shim material 603  a second shim-shim transition zone 606 (for example  a second fusion zone) between the second shim material 608 and the third shim material 603  the first shim-alloy transition region 514 between the first shim material 506 and the first alloy 104  and the second shim-alloy transition region 516 between the second shim material 510 and the second alloy 108. In this embodiment  the first region 504 and the second region 508 have substantially identical thicknesses 306 and the third region 601 has a greater thickness 306.
[0032] Referring to FIG. 7  in one embodiment  the first shim 112 and the second shim 114 have different thicknesses 306 (for example  the first shim 112 having a thickness of about 0.01 inches and the second shim 114 having a thickness of about 0.02 inches or the first shim 112 having a thickness of about 0.02 inches and the second shim 114 having a thickness of about 0.03 inches). Upon receiving the energy from the energy beam 118  the first shim 112 and the second shim 114 form the weld 110 having the gradient 502 including the first region 504 of the first shim material 506  the second region 508 of the second shim material 510  the shim transition region 512 between the first shim material 506 and the second shim material 510  the first shim-alloy transition region 514 between the first shim material 506 and the first alloy 104  and the second shim-alloy transition region 516 between the second shim material 510 and the second alloy 108. In this embodiment  the first region 504 and the second region 508 have different thicknesses 306.
[0033] Referring to FIG. 8  in one embodiment  the first shim 112 and the second shim 114 have substantially identical thicknesses 306 and the third shim 602 has a different thickness 306 (for example  the first shim 112 and the second shim 114 having thicknesses of about 0.01 inches and the third shim 602 having a thickness of about 0.02 inches or the first shim 112 and the second shim 114 having thicknesses of about 0.02 inches and the third shim 602 having a thickness of about 0.03 inches). Upon receiving the energy from the energy beam 118  the first shim 112  the second shim 114  and the third shim 602 form the weld 110 having the gradient 502 including the first region 504 of the first shim material 506  the second region 508 of the second shim material 510  the third region 601 of the third shim material 603  the first shim-shim transition zone 604 between the first shim material 506 and the third shim material 603  the second shim-shim transition zone 606 between the second shim material 510 and the third shim material 603  the first shim-alloy transition region 514 between the first shim material 506 and the first alloy 104  and the second shim-alloy transition region 516 between the second shim material 510 and the second alloy 108. In this embodiment  the first region 504 and the second region 508 have substantially identical thicknesses 306 and the third region 601 has a greater thickness 306.
[0034] The shims 111 are selected and positioned corresponding to one or more of the properties and/or compositions of the first alloy 104 and/or the second alloy 108 and the properties and/or compositions of adjacent shims. For example  in one embodiment  the first shim 112 includes a composition and/or property compatible with the first alloy 104 and is positioned proximal to the first portion 102 including the first alloy 104. For example  in one embodiment  the composition include Al  Ti  or any other suitable component at a predetermined concentration for compatibility. In this embodiment  the second shim 114 includes a composition and/or property compatible with the second alloy 108 and is positioned proximal to the second portion 106 including the second alloy 108. In one embodiment  the first shim 112 and the second shim 114 include compatible compositions and are positioned adjacent to each other for welding. In another embodiment  the third shim 602 is positioned between the first shim 112 and the second shim 114 and includes a composition providing additional desired properties (for example  strength and/or compatibility with each of the first shim 112 and the second shim 114).
[0035] In one embodiment  the shims 111 are selected and positioned based upon chemistry of the alloys. For example  in one embodiment  the first alloy 104 is a casting superalloy and the first shim 112 includes low aluminum content (for example  by weight  below about 3% with about 0% titanium  below about 2.5% with about 1% titanium  below about 2% with about 2% titanium  or linear interpolations or extrapolations thereof). In this embodiment  material within the fusion boundary (for example  the shim transition zone 512  the first shim-shim transition zone 604  the second shim-shim transition zone 606  or combinations thereof) is within the weldable material range  thereby reducing or eliminating strain age cracking in the heat affected zone of the first alloy 104.
[0036] In one embodiment  the first alloy 104 is a casting superalloy and one or more of the shims 111 is selected for high ductility (for example  based upon elongation being between about 30% and about 65% or between about 55% and about 65%). In this embodiment  the weld 110 is resistant to liquation cracking  such as centerline cracking. In another embodiment  one or more of the shims 111 is selected to include low gamma prime volume.
[0037] In one embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 has a composition  by weight  of about 20% to about 24% chromium  about 3% iron  about 0.3% to about 1% magnesium  about 1% to about 3% molybdenum  about 0.2% to about 0.5% aluminum  and a remainder nickel.
[0038] In one embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 has a composition  by weight  of about 20% to about 24% chromium  about 3% iron  about 1% magnesium  about 8% to about 10% molybdenum  about 1% silicon  and a remainder nickel.
[0039] In one embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 has a composition  by weight  of about 14.5% to about 16.5% chromium  about 4% to about 7% iron  about 1% magnesium  about 15% to about 17% molybdenum  about 0.8% silicon  and a remainder nickel.
[0040] In one embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 includes a nickel-based alloy having  by weight  up to about 22% chromium  up to about 13% cobalt  up to about 3% iron  and up to about 9% molybdenum. In a further embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 has a composition  by weight  of about 22% chromium  about 12.5% cobalt  about 1.1% aluminum  0.1% carbon  about 3% iron  about 1% manganese  about 1% silicon  about 0.6% titanium  about 9% molybdenum  and a balance of nickel.
[0041] In one embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 includes a nickel-based alloy having  by weight  up to about 3% iron  up to about 20% chromium  up to about 3% manganese. In a further embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 has a composition  by weight  of about 3% iron  about 20% chromium  about 0.5% silicon  about 3% manganese  about 0.7% titanium  about 0.1% carbon and a balance of nickel.
[0042] In one embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 includes a nickel-based alloy  having  by weight  up to about 22% chromium  up to about 14% tungsten  and up to about 2% molybdenum. In a further embodiment  at least one of the first shim material 506  the second shim material 510  and the third shim material 603 has a composition  by weight  of about 0.1% carbon  about 1% iron  about 22% chromium  about 14% tungsten  about 1.5% molybdenum  about 0.5% manganese  about 0.4% silicon  about 0.3% aluminum  about 0.02% lanthanide  about 0.004% boron  and a balance of nickel.
[0043] While the invention has been described with reference to a preferred embodiment  it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition  many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore  it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention  but that the invention will include all embodiments falling within the scope of the appended claims.

CLAIMS
What is claimed is:
1. A welded component  comprising:
a first alloy subcomponent;
a second alloy subcomponent; and
a weld between the first alloy subcomponent and the second alloy subcomponent;
wherein the weld includes a gradient having a transition region.
2. The welded component of claim 1  wherein the first alloy subcomponent and the second alloy subcomponent have same composition.
3. The welded component of claim 1  wherein the first alloy subcomponent has a first composition and the second alloy subcomponent has a second composition  the first composition differing from the second composition.
4. The welded component of claim 3  wherein the first composition is a nickel-based alloy including  by weight  up to about 15% chromium  up to about 10% cobalt  up to about 4% tungsten  up to about 2% molybdenum  up to about 5% titanium  up to about 3% aluminum  and up to about 3% tantalum.
5. The welded component of claim 3  wherein the first composition is a nickel-based alloy including  by weight  up to about 10% chromium  up to about 8% cobalt  up to about 4% titanium  up to about 5% aluminum  up to about 6% tungsten  and up to about 5% tantalum.
6. The welded component of claim 3  wherein the first composition is a nickel-based alloy including  by weight  up to about 8% cobalt  up to about 7% chromium  up to about 6% tantalum  up to about 7% aluminum  up to about 5% tungsten  up to about 3% rhenium  and up to about 2% molybdenum
7. The welded component of claim 3  wherein the first composition is a nickel-based alloy including  by weight  up to about 10% chromium  up to about 8% cobalt  up to about 5% aluminum  up to about 4% titanium  up to about 2% molybdenum  up to about 6% tungsten  and up to about 5% tantalum.
8. The welded component of claim 3  wherein the first composition is nickel-based alloy including  by weight  up to about 10% cobalt  up to about 8% chromium  up to about 10% tungsten  up to about 6% aluminum  up to about 3% tantalum  and up to about 2% hafnium.
9. The welded component of claim 1  wherein the gradient includes a first region of a first shim material formed by a first shim  a second region of a second shim material formed by a second shim  a first shim-alloy transition region between the first shim material and the first alloy subcomponent  and a second shim-alloy transition region between the second shim material and the second alloy subcomponent.
10. The welded component of claim 9  wherein the first region and the second region have substantially identical thicknesses.
11. The welded component of claim 9  wherein the first region and the second region have different thicknesses.
12. The welded component of claim 9  wherein the first shim is a nickel-based alloy including  by weight  up to about 22% chromium  up to about 13% cobalt  up to about 3% iron  and up to about 9% molybdenum.
13. The welded component of claim 9  wherein the first shim is a nickel-based alloy including  by weight  up to about 3% iron  up to about 20% chromium  and up to about 3% manganese.
14. The welded component of claim 9  wherein the first shim is a nickel-based alloy including  by weight  up to about 22% chromium  up to about 14% tungsten  and up to about 2% molybdenum.
15. The welded component of claim 1  wherein the gradient includes a first region of a first shim material formed by a first shim  a second region of a second shim material formed by a second shim  a third region of a third shim material formed by a third shim  the first shim-shim transition region between the first shim material and the third shim material  a second shim-shim transition region between the second shim material and the third shim material  a first shim-alloy transition region between the first shim material and the first alloy subcomponent  and a second shim-alloy transition region between the second shim material and the second alloy subcomponent.
16. The welded component of claim 15  wherein the first region and the third region have different thicknesses.
17. The welded component of claim 1  wherein the component is a gas turbine component.
18. A welded gas turbine component  comprising:
a first alloy;
a second alloy; and
a weld positioned between the first alloy and the second alloy;
wherein the weld is formed by a first shim and a second shim being beam welded.
19. A process of welding a component  comprising:
positioning a first alloy;
positioning a second alloy;
positioning a first shim and a second shim between the first alloy and the second alloy; and
beam welding the first shim and the second shim to form a weld between the first alloy and the second alloy.
20. The process of claim 19  wherein the beam welding is electron beam welding.