回火温度与钛含量对低合金耐磨钢组织及性能的影响

Effect of tempering temperature and titanium on content microstructure and mechanical properties of low alloy wear resistant steels

对两种不同Ti含量的低合金耐磨钢进行淬火后在160~540℃温度区间回火处理。结合冲击性能、力学性能及磨损实验的测试结果,利用SEM,TEM等对不同热处理状态实验钢的微观组织及析出相的分析,研究了回火工艺及组织演变对性能影响。结果表明,两组实验钢在190℃回火,均得到回火马氏体,回火马氏体形态仍然为板条状,板条间有(Nb,Ti,V)碳化物析出;而500℃回火时,马氏体板条消失,得到回火索氏体组织。两组实验钢淬火后在190℃与500℃回火时-20℃冲击功出现峰值,分别为40 J与60 J,其中Ti含量为0.09%的2号实验钢淬火及在190℃回火后,综合力学性能最佳,其屈服强度为1218 MPa,抗拉强度1507 MPa、硬度429.5 HV,伸长率17.5%,抗磨损性能也优于Ti含量较高(0.18%)的1号实验钢。

Two kinds of low alloy wear resistant steels with different content of Ti were quenched and tempered in the temperature range of 160-540 ℃. The effects of tempering process and microstructure evolution on the properties of the steel was investigated based on the testing results of impact toughness, wear resistance and mechanical properties, as well as the SEM and TEM characterization of microstrueture of the steels after different heat treatment. The results show that the tempering lath martensite is obtained in the two steels after tempering at 190 ℃ , and （ Nb,Ti, V） C carbides precipitate in the interface of the lath martensite. The lath martensite disappears after tempering at 500 ℃ , and tempering sorbite is obtained. The peak value of - 20 ℃ impact energy after tempering at 190 ℃ and 500 ℃ is about 40 J and 60 J, respectively. The steel with content of Ti of 0.09% has optimal mechanical properties after tempering at 190 ℃ , with the yield strength, tensile strength, hardness and elongation are 1218 MPa, 1507 MPa, 429. 5 HV and 17.5% , respectively, and its wear resistance is better than that of the steel with content of Ti of 0. 18%.