precipitation hardening(By adding elements such as 3 per cent copper or aluminium with about 1 per cent titanium to steels containing 17 per cent chromium and 4 to 8 per cent nickel, heat-treatment involving precipitation hardening and / or refrigeration at - 70°C can be applied, and strengths of up to 1500 newtons per sq. mm can be obtained. 通过向含有17% 的铬和4% ~8% 的镍的钢中加人3%的铜或铝以及约 1%的钛，还可以进行包括沉淀硬化在内的热处理和/或在 -70°C 下致冷，由此可获得强度高达1500 N/ mm² 的钢。)
