氮含量对P92耐热钢组织与性能的影响

INFLUENCE OF NITROGEN CONTENT ON MICRO-STRUCTURE AND MECHANICAL PROPERTIES OF P92 HEAT RESISTENT STEEL

通过对5组不同含氮量P92耐热钢的室温、高温拉伸试验及显微组织检验,研究了氮含量对P92耐热钢的显微组织和力学性能的影响。结果表明:随着氮含量增加,钢的室温强度和高温强度提高,延伸率和屈强比显著降低;铁素体含量明显减少,氮化物析出量增多,钢的晶粒度明显细化。但钢中氮含量过高,钢锭在锻造过程中表面易开裂,从而显著影响其表面质量。根据生产实际,P92耐热钢中氮含量应控制在成分中上限0.045%～0.060%之间比较适宜。

The effect of nitrogen on the microstructure and mechanical properties of P92 heat resistant steel with different nitrogen contents was investigated by room temperature and high temperature tension testing. Results showed that with the increasing of nitrogen content, the room temperature strength and high temperature strength increased, while the elongation and yield strength ratio de- creased, the ferrite content decreased obviously, the nitride precipitations increased, and the grain size refined. However, with excessive nitrogen content, the steel surface was more inclined to crack, thus influencing the surface quality of steels. Therefore, it was appropriate to control the nitrogen content of P92 heat resistant steel in production between 0. 045% and 0. 060%.