【摘要】 以自主设计的稀土改性Si-Mn-B系贝氏体-马氏体复相耐磨钢为研究对象,利用正交试验研究了不同淬火温度、淬火保温时间、回火温度、回火时间对材料强度、冲击功的影响,以确定最佳热处理工艺,并利用XRD、OM、SEM、TEM方法对其最佳热处理工艺组织进行分析。结果表明:淬火温度对抗拉强度影响最大,回火温度对屈服强度的影响最大,淬火保温时间对冲击功的影响最大。最优热处理方案为:900℃×1.5 h油淬+300℃×3 h回火处理。按此方案热处理后有较好的强韧配合:抗拉强度为1903 MPa,屈服强度为1591 MPa,洛氏硬度为51.4 HRC,无缺口冲击功为267 J。采用彩色金相-化学腐蚀法,组织为下贝氏体(49.6%)、板条马氏体(43.9%)和少量残留奥氏体(6.5%)。更多还原

【Abstract】 For a rare earth modification Si-Mn-B wear-resistant steel with bainite-martensite multi-phase,which was designed by authors,orthogonal tests were used to determine the best heat treatment process.The influences of quenching temperature and holding time,tempering temperature and holding time on the strength and impact energy of the tested steel were investigated.The microstructure of the steel was studied by X-ray diffraction(XRD),optical microscope(OM),scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS).The results show that quenching temperature affected tensile strength most,the influence of tempering temperature on yield strength is the most important,the influence of quenching soaking time on impact energy is the largest.The optimal heat treatment process is 900 ℃ for 1.5 h oil quenching and tempering at 300 ℃ for 3 h.The steel exhibits the best strength-toughness combination after heat treated as proposed,with the tensile strength of 1903 MPa,yield strength of 1591 MPa,hardness of 51.4 HRC,impact energy of 267 J.The microstructure consists primarily of lower bainite(49.6%),lath martensite(43.9%) and a small amount of retained austenite(6.5%),according to micrographs obtained by a color metallography-chemical-etching method.更多还原