Patent ID: 9687902
Date: 2017-06-27
CPC Classifications: B21D,B23P,B32B,B65D,C21D,F17C

Claim:
1. A method for treating metal, comprising: providing a metal, the metal possessing an initial yield strength; and incrementally applying an increasing autofrettage pressure to the metal to produce an autofrettaged yield strength, without heat soaking; whereby the autofrettaged yield strength is increased over the initial yield strength by a percentage selected from a group of percentages consisting of: ≧10%, ≧20%, ≧30%, ≧40%, and ≧50%; wherein the incrementally applying the increasing autofrettage pressure comprises performing two or more cycles of autofrettage of the metal; wherein each cycle of incrementally applying the increasing autofrettage pressure sequentially comprises: wherein the prescribed gage pressure is 6000 psiq ±2%; and wherein the prescribed pressure of each cycle of autofrettage is sequentially stepped through: