混合稀土(La-Ce)对30MnCrNiMo钢组织与性能的影响

Effect of Mixed Rare Earth Elements(La-Ce)on Microstructure and Properties of 30MnCrNiMo Steel

为了改善30MnCrNiMo钢板的综合力学性能,向钢中加入微量混合稀土元素,借助全自动淬火膨胀仪测定钢的相变点,制定了钢的热处理工艺,通过显微组织观察及冲击、拉伸性能测试,研究了含稀土与不含稀土两组试验钢的组织与力学性能。结果表明,加入混合稀土La-Ce后,提高了钢的A_(c1)、A_(c3)相变点温度,降低了钢的Bs、Bf相变点温度,提升了钢的贝氏体的显微硬度,改善了回火马氏体组织、细化了奥氏体晶粒,变质了钢中夹杂物,提升了钢的冲击性能和拉伸性能,室温冲击功和-40℃低温冲击功分别提升了16.8%和17.4%,抗拉强度、屈服强度和断后伸长率分别提升了15.2%、4.5%和8.3%。

In order to improve the comprehensive mechanical performance of 30MnCrNiMo steel,mixed rare earth ele-ments(La-Ce)were added to the steel.With the help of full automatic transformation measuring apparatus,the phase change temperature of steel had been measured to make the heat treatment process.Two groups of test steel with RE and without RE were studied by observation of microstructure and impact,tensile properties test.Results show that after mixed rare earth La-Ce added to the steel,the phase transition points of A_(c1) and A_(c3) are increased,while the phase transition points of B,and Br are reduced significantly,and the micro-hardness of bainite is improved,the tempered martensite structure and austenite grain are refined,the inclusions in the steel are deteriorated,which improve impact and tensile properties of the steel.The impact performance of room temperature and-40℃increases by 16.8%and 17.4%,and the tensile strength,yield strength and e-longation are increased by 15.2%,4.5%and 8.3%,respectively.