Surface treatment of austenitic Ni-Fe-Cr based alloys for improved resistance to intergranular corrosion and intergranular cracking
US6610154B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 27, 2001 |
| Grant date | Aug 26, 2003 |
| Priority date | — |
| Expiry date | Dec 6, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D2251/04
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A surface treatment process for enhancing the resistance to intergranular corrosion and intergranular cracking of components fabricated from austenitic Ni—Fe—Cr based alloys comprising the application of surface deformation to the component, to a depth in the range of 0.01 mm to 0.5 mm, for example by high intensity shot peening below the recrystallization temperature, followed by recrystallization heat treatment, preferably at solutionizing temperatures. The surface deformation and annealing process can be repeated to further optimize the microstructure of the near-surface region. Following the final heat treatment, the process optionally comprises the application of further surface deformation (work) of reduced intensity, yielding a worked depth of between 0.005 mm to 0.01 mm, to impart residual compression in the near surface region to further enhance cracking resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.