Mn对Nb-Ti微合金高强钢组织、性能和氢致断裂影响的研究

Effect of Mn on Microstructure, Properties and Hydrogen Induced Cracking of Nb-Ti Microalloyed High Strength Steel

设计了三种不同Mn含量的Nb-Ti微合金高强钢,研究了Mn含量对该钢组织以及氢致断裂性能的影响。结果表明,随着Mn含量增加,钢的氢致断裂敏感性增大。Mn含量增加,钢中的各相转变温度降低。随Mn含量增加,相变逐渐由铁素体相变为主转变成贝氏体相变为主。当Mn含量为1.81wt%时,组织中出现马氏体,导致Mn含量高的钢种出现氢致开裂。添加Mn有利于提高Nb-Ti微合金高强钢的强度,但同时会增加钢的氢致断裂敏感性。

Three high strength Nb-Ti microalloyed steels with different Mn contents were designed to investigate the effect of Mn content on the microstructure and hydrogen induced cracking of the steels. The results show that with Mn content increasing, the sensibility of hydrogen induced cracking of the steel increases. The phase transformation temperatures tend to decrease with Mn content increasing. The type of phase transition changes from most ferrite transformation to main bainite transformation with the increase of Mn content. When the Mn content is 1.81 wt%, martensite presents in the microstructure,which can lead to the appearance of hydrogen induced cracking in the steel with high content of Mn. Mn addition can enhance the strength of Nb-Ti microalloyed steel, but can also increase the sensibility of hydrogen induced cracking of the steel.