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In some examples, a material may be subject to shot peening of a relatively long duration to improve cavitation erosion resistance of the material. For example, the material surface may be shot peened to cause grain reduction and an increase in hardness to a depth of 60 μm or more, while the surface

In some examples, a material may be subject to shot peening of a relatively long duration to improve cavitation erosion resistance of the material. For example, the material surface may be shot peened to cause grain reduction and an increase in hardness to a depth of 60 μm or more, while the surface remains relatively smooth. As one example, the method may include treating a surface of austenitic stainless steel by impacting the surface with shot media for a treatment duration of 15 to 40 minutes at a shot peening intensity corresponding to an Almen strip type A intensity of 5A to 10A.

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1. A method of treating a surface of austenitic stainless steel to increase resistance to cavitation erosion, the method comprising impacting the surface with shot media for a shot peening duration of 15 to 40 minutes at a shot peening intensity corresponding to an Almen strip type A intensity of 5A

1. A method of treating a surface of austenitic stainless steel to increase resistance to cavitation erosion, the method comprising impacting the surface with shot media for a shot peening duration of 15 to 40 minutes at a shot peening intensity corresponding to an Almen strip type A intensity of 5A to 10A. 2. The method as recited in claim 1, wherein the shot media is cast steel shot having a size range between 0.18 mm to 1.68 mm. 3. The method as recited in claim 1, wherein the shot peening duration is between 20 and 30 minutes. 4. The method as recited in claim 3, wherein the shot peening intensity is in a range from 5A to 7A, and the shot media is steel shot having a size range from 0.58 mm to 0.99 mm. 5. The method as recited in claim 1, further comprising polishing the surface to remove 10 to 30 μm of material. 6. The method as recited in claim 1, wherein the austenitic stainless steel includes 18-20% Cr and 2.0-3.0% Mo. 7. The method as recited in claim 1, wherein the treatment provides an increase in hardness to a depth of at least 60 μm from the surface and a surface roughness of less than 20 μm. 8. A method comprising shot peening a surface of a material for a shot peening duration of 15 to 40 minutes at a shot peening intensity corresponding to an Almen strip type A intensity of 5A to 10A, wherein: the material has an austenitic crystalline structure, anda shot media used during the shot peening has a hardness greater than the material when the material is in an annealed condition. 9. The method as recited in claim 8, wherein the shot media is cast steel shot having a size range between 0.18 mm to 1.68 mm. 10. The method as recited in claim 8, wherein the shot peening duration is between 20 and 30 minutes. 11. The method as recited in claim 8, wherein the shot peening intensity is in a range from 5A to 7A, and the shot media is steel shot having a size range from 0.58 mm to 0.99 mm. 12. The method as recited in claim 8, further comprising: following the shot peening, determining that a roughness of the surface exceeds 20 μm; anddecreasing at least one of: a shot media size, orthe shot peening intensity while maintaining the shot peening intensity within a range of 5A-10A. 13. The method as recited in claim 8, further comprising: following the shot peening, determining that a depth of an increased hardness layer is less than 60 μm; andincreasing at least one of: the shot peening intensity while maintaining the shot peening intensity within a range of 5A-10A, orthe shot peening duration, while maintaining the duration within a range of 15-40 minutes. 14. The method as recited in claim 8, wherein the material is an austenitic stainless steel including 18-20% Cr and 2.0-3.0% Mo. 15. A method comprising: impacting a surface of a material having an austenitic crystalline structure with shot media for a duration ranging from 15 and 40 minutes at an Almen strip type A intensity ranging from 5A to 10A; andpolishing the surface to remove 10 to 20 μm of the material. 16. The method as recited in claim 15, wherein the shot media is cast steel shot having a size range between 0.18 mm to 1.68 mm. 17. The method as recited in claim 15, wherein the duration ranges between 20 and 30 minutes. 18. The method as recited in claim 17, wherein the shot peening intensity is in a range from 5A to 7A, and the shot media is steel shot having a size range from 0.58 mm to 0.99 mm. 19. The method as recited in claim 15, wherein the material is austenitic stainless steel including 18-20% Cr and 2.0-3.0% Mo. 20. The method as recited in claim 15, wherein following the shot peening, prior to the polishing, determining that a roughness of the surface exceeds 20 μm; anddecreasing at least one of: a shot media size, orthe shot peening intensity while maintaining the shot peening intensity within a range of 5A-10A.