碳含量对GC-4钢组织与性能的影响

EFFECT OF THE CARBON CONTENT ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF GC-4 STEEL

本文用光学和电子显微镜研究了碳含量在0.39%～0.42%间变化对 GC-4型钢显微组织(190℃等温、260℃回火)的影响。讨论了显微组织与力学性能间的关系。结果表明,碳含量低于0.40%的钢比碳含量大于0.40%的钢具有较好的强韧性配合。随着碳含量的进一步增加,抗拉强度增加幅度不大,而屈服强度反而有下降趋势。为了获得较好的强韧性配合,应将碳含量控制在0.40%以内。

The effect of carbon content within 0.38% to 0.40% on the microstructure of GC-4 ultra-high strength steels after isothermal transformation and low temperature tempering has been studied in the present investigation,and the re- lationship between the microstructure and mechanical properties of the steels has been discussed.The results show that the steels with the carbon content lower than 0.40% have better strength-toughness conbinations than those with the car- bon content greater than 0.40%.It has been found that with the further incre- ment of carbon content the ultimate tensile strength increased slightly,but the yield strength of the steel showed the decreasing trend.Therefore,in order to obtain a better conbination of strength and toughness,it is reasonable that the carbon content of GC-4 steel should be controlled below 0.40%.