| 摘要 |
PURPOSE:To provide a titled bolt suitable for use in fastening of Al alloy parts, etc. by specifying the compsn. of a steel consisting of C, Si, Mn, Ni, S and Fe and regulating the cold reduction ratio for drawing after rolling and soln. heat treatment and forming temp. CONSTITUTION:A steel contg. 0.5-0.8wt% C, 0.1-1% Si, 10-20% Mn, 0.5-2% Ni and <=0.05%, more preferably <=0.02% S, contg. further 0.02-0.2% N and consisting of the balance Fe and unavoidable impurities is used as a blank material. The blank material is formed at 15-30% cold reduction ratio in drawing after rolling and soln. heat treatment and at <=600 deg.C, more preferably <=350 deg.C, by which a high-strength high-expansion bolt is obtd. This bolt is suitable for use in fastening Al parts, etc. having the coefft. of thermal expansion higher than the coefft. of expansion of Fe parts.
|
