热处理对耐磨铸造Fe-C-B合金组织及性能的影响

Effect of heat treatment on microstructure and properties of wear resistant cast Fe-C-B alloy

用光学显微镜、扫描电镜、透射电镜和销盘式磨损试验机研究了硼含量0．5wt％～2．0wt％和碳含量≤0．2wt％的铸造Fe—C—B合金热处理后的组织和性能，并对铸造Fe—C—B合金进行了销盘磨粒磨损试验。试验结果表明：铸造Fe—C—B合金的凝固组织为Fe2B相和珠光体、铁素体基体，Fe2B相呈鱼骨状和网状分布。Fe—C—B合金经950～1100％水淬＋200℃回火处理后，局部出现断网现象，基体全部转变为板条马氏体。随着淬火温度增加，№B相断网现象明显，基体中会出现少量片状马氏体。铸造Fe-C-B合金热处理后的硬度为55～60HRC，冲击韧度大于10J/cm^2，动态断裂韧度大于30MPa·m^1/2。在120目石英砂磨粒磨损条件下，Fe—C—B合金的耐磨性优于高锰钢，比高铬白口铸铁稍低。

The mierostrueture and properties of east Fe-C-B alloy containing 0.5 % - 2.0 wt% B and lower than 0.2 wt% C after heat treatment were investigated by means of optical microscopy（OM）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and wear test. The results show that the solidification microstructure of the cast Fe-C-B alloy consists of Fe2 B type boride and pearlite and ferrite matrix. The distribution of borides is in the form of fishbone and network. After water quenching at 950 - 1100℃ and tempering at 200℃, the broken boride network is observed and the matrix transforms to lath martensite in the alloy. When the quenching temperature increases, more broken borides are found, and there is a few plate martensite in the matrix. Hardness of the cast Fe-C-B alloy after heat treatment is 55 - 60 HRC, its impact toughness and fracture toughness are more than 10 J/cm^2 and 30 MPa·m^1/2 ,respectively. Using 120 mesh quartz as abrasive, the wear resistance of cast Fe-C-B alloy under abrasive wearing is higher than that of high manganese steel and slightly lower than that of high chromium white cast iron.