Patent ID: 6282939
Filing Date: 2001-09-04
Classification: B21D

Abstract:
A method for producing a metal bellows of a length of ""Ls"" for use in a heated atmosphere, comprising the steps of:(a) preparing a blank of the bellows, the blank being a stainless steel metal pipe having a plurality of bulges formed therearound, the blank having a length ""L"" that is longer than the length ""Ls"" of the finally produced metal bellows;(b) axially compressing the blank by a length of ""a"", so that the compressed blank has a length of ""L-a"" that is shorter than the length ""Ls"";(c) axially expanding the compressed blank so that the expanded blank has a length of ""L-a +b"" that is longer than the length ""Ls"" but shorter than the length of ""L"";(d) removing the force that has been applied to the blank for expanding the same; and(e) leaving the treated blank in a room temperature until the time when the treated blank becomes to have the length of ""Ls"" due to the spring back phenomenon.