低合金高强度耐磨钢板NM500的研发

Development of high strength low alloy wear-resistant steel plate NM500

采用Ti-Mo-B合金化体系,通过洁净钢冶炼技术、控制轧制技术以及离线淬火、回火工艺,成功开发出一种低合金高强度耐磨钢板NM500。通过光学显微镜(OM)、扫描电镜(SEM)和透射电镜(TEM)观察试验钢的显微组织,利用万能试验机、摆锤冲击试验机和布氏硬度仪分别检测试验钢的强度、低温韧性和硬度。结果表明,所开发的NM500钢板显微组织为回火板条马氏体,板条内分布着长度50～100 nm,宽约10 nm的ε碳化物以及纳米尺度的微合金元素碳氮化物(Ti,Nb)(C,N),其抗拉强度为1678 MPa,伸长率12.5%,布氏硬度502 HBW,-20℃冲击吸收能量38 J,具有良好的强度、塑性和低温韧性。在相同磨损条件下,所研制的NM500钢的相对耐磨性约为NM400钢的1. 45倍,NM450钢的1. 2倍。

Based on the Ti-Mo-B alloying system,a high strength low alloy wear resistant steel plate NM500 was developed through clean steel smelting technology,thermal mechanical control process and off-line quenching and tempering process. The microstructure of the steel was observed by means of optical microscope (OM),scanning electron microscopy (SEM) and transmission electron microscopy (TEM),the strength,toughness and hardness of it were tested by means of universal testing machine,pendulum impact testing machine and Brinell hardness tester. The results indicate that the microstructure of the obtained NM500 steel is tempered lath martensite,where ε carbides with a length of about 50-100 nm and a width of about 10 nm and nanoscale (Ti,Nb)(C,N) are distributed. Moreover,its tensile strength is1678 MPa,elongation is 12. 5%,hardness is 502 HBW,the impact absorbed energy at-20 ℃ is 38 J,and the relative wear resistance is1. 45 times higher than that of NM400 steel and 1. 2 times higher than that of NM450 steel under the same wear conditions.