| 摘要 |
PURPOSE:To inexpensively produce the thin-walled cylinders which are better in both strength and toughness than conventional ones by subjecting the steel of the specific component composition to the specific heat treatment and spinning. CONSTITUTION:A steel contg. 0.05-0.3% C, <=0.1% Si, <=0.1% Mn, 6.0-12.0% Ni, 0.5-5.0% Mo, 0.1-2.0% Ti and 0.1-2.0% Al, and if necessary, 1.0-8.0% Co other than the above-mentioned components and residual % iron and unavoidable impurities is heated to >=800 deg.C temperature to dissolve alloy elements sufficiently to prepare a solid solution. Thence, it is subjected to working of >=30% reduction rate at a temperature region above the martensite transformation initiation temperature (MS point) and not exceeding 700 deg.C. Thence, it is subjected to spinning of >=30% working rate in a temperature range between ordinary temp. and 500 deg.C. After this, it is subjected to tempering with in 100-300 deg.C temperature range to remove the strain whereby the strength and toughness are enhanced by the strain ageing. |
