| 摘要 |
PURPOSE:To produce formed bellows having excellent workability and good durability by working a molding made of thin steel sheets of a precipitation hardened stainless steel subjected to a soln. heat treatment to form the formed bellows, then subjecting the bellows to a precipitation hardening heat treatment. CONSTITUTION:A gas chamber 21 into which a compressed gas in an outside cylinder 2 of a suspension device 1 for vehicles is sealed and a liquid chamber 20 in which oil is filled are partitioned by the metallic bellows. This bellows 22 is formed by forming the thin sheets made of the precipitation hardening type stainless steel to a cylindrical shape, then subjecting the same to the soln. heat treatment by heating for about 30min at about, for example, 1,040 deg.C, then by air cooling. The cylinder is then formed to a bellows shape by plastic working such as bulging or roll forming and is subjected to the precipitation hardening heat treatment by holding for about one and half hour at 760 deg.C and air cooling, then further holding for about one and half hour at 565 deg.C and air cooling. The formed bellows having the extremely good durability is obtd. |
