Weldability of alloys with directionally-solidified grain structure
View Patent ↗A method of welding alloys having directionally-solidified grain structure. The methods improve the weldability of these alloys by creating a localized region of fine grain structure, wherein the welding occurs in these localized regions. The localized regions are formed by applying strain energy using a variety of different methods, such as by hammer peening, laser peening or sand blasting. Then, a heat treatment step may be used to create recrystallized grains having the fine grain structure. The region of fine grain structure provides better weldability.
1. A method for welding alloys having a directionally-solidified grain structure comprising:
breaking down a portion of the directionally-solidified grain structure in an area to be welded;
recrystallizing grains in the portion of the directionally-solidified grain structure in the area to be welded to form a localized region of grains having a fine grain structure, and
welding the alloys in the localized region of grains having a fine grain structure.
2. The method of claim 1 , wherein energy is applied to break down the portion of the directionally-solidified gram structure in the area to be welded.
3. The method of claim 2 , wherein strain energy is applied to break down the portion of the directionally-solidified grain structure in the area to be welded.
4. The method of claim 3 , wherein the strain energy is applied using a method selected from hammer peening, shot peening, laser peening, grit and sand blasting, or a combination thereof.
5. The method of claim 3 , wherein the strain energy is applied in an amount sufficient to cause plastic deformation of the directionally-solidified grains in the area to be welded.
6. The method of claim 1 , wherein the grains in the portion of the directionally-solidified grain structure in the area to be welded are recrystallized using a heat treatment step.
7. The method of claim 6 , wherein the heat treatment step is selected from mill anneal, recrystallize anneal, solution treatment and aging, or a combination thereof.
8. The method of claim 1 , wherein fusion welding is used for welding the alloys in the localized region of grains having a fine grain structure.
9. The method of claim 8 , wherein the fusion welding is selected from arc welding, electron beam welding, flash welding, laser welding, or a combination thereof.
10. A method for repairing a turbine component having a directionally-solidified grain structure in at least a portion of the turbine component comprising:
breaking down a portion of the directionally-solidified grain structure in the turbine component;
recrystallizing grains in the portion of the directionally-solidified grain structure in the turbine component to form a localized region of grains having a fine grain structure; and
welding the localized region of grains having a fine grain structure.
11. The method of claim 10 , wherein energy is applied to break down the portion of the directionally-solidified grain structure in the turbine component.
12. The method of claim 11 , wherein strain energy is applied to break down the portion of the directionally-solidified grain structure in the turbine component.
13. The method of claim 12 , wherein the strain energy is applied using a method selected from hammer peening, shot peening, laser peening, grit and sand blasting, or a combination thereof.
14. The method of claim 12 , wherein the strain energy is applied in an amount sufficient to cause plastic deformation of the directionally-solidified grains in the portion of the turbine component.
15. The method of claim 10 , wherein the grains in the portion of the directionally-solidified grain structure in the turbine component are recrystallized using a heat treatment step.
16. The method of claim 15 , wherein the heat treatment step is selected from mill anneal, recrystallize anneal, solution treatment and aging, or a combination thereof.
17. The method of claim 10 , wherein fusion welding is used for repairing the turbine component.
18. The method of claim 17 , wherein the fusion welding is selected from arc welding, electron beam welding, flash welding, laser welding, or a combination thereof.