| 摘要 |
Steel having a structure of ferrite and tempered martensite and exhibiting excellent vibration attenuation characteristic is manufactured by the steps of forming a solid solution of steel consisting essentially of 0.02 DIFFERENCE 0.016% by weight of carbon; less than 0.6% by weight of silicon; 0.5 DIFFERENCE 1.5% by weight of manganese; either one or more of 5 DIFFERENCE 15% by weight of chromium and 2 DIFFERENCE 9% by weight of tungsten; either one or both of 0.03 DIFFERENCE 2% by weight of aluminum and 0.1 DIFFERENCE 5% by weight of cobalt; less than 1.5% by weight of copper, if necessary, and the balance of iron; heating and keeping for a desired time period the alloyed steel in a temperature range in which austenite and ferrite coexist; cooling the steel so as to transform austenite to martensite; and tempering the steel at a temprature of from 400 DEG C. to a temperature below a transformation point thus forming a structure of ferrite and martensite. Steel incorporated with copper is suitable for precipitation hardening. Advantageously, the amount of the tempered martensite should be less than 60% by volume. |
