耐磨铸造Fe-B-C合金的研究

A STUDY OF ABRASION RESISTANT CAST Fe-B-C ALLOY

借助光学显微镜、扫描电镜和X射线衍射分析等手段,研究了硼(B)含量>2．0％和碳(C)含量<0．2％的铸造 Fe-B-C合金的凝固组织及热处理后的组织和性能．铸造Fe-B-C合金的凝固组织由Fe2B、铁素体和珠光体组成,硼化物呈网状沿晶界分布．Fe-B-C合金经950℃正火处理后,局部出现断网现象,基体组织全部转变为板条马氏体,硬度大幅度提高, HRC接近60,冲击韧度大于10 J／cm2,动态断裂韧度大于30 MPa·m1/2．在干滑动磨损条件下,Fe-B-C合金的耐磨性优于镍硬白口铸铁和GCr15、Cr12MoV等合金钢,与高铬白口铸铁相当．Fe-B-C合金熔炼简便、铸造性能好,且不含Ni 和MO等昂贵合金元素,具有较低的生产成本．

The solidification structures of cast Fe-B-C alloy containing more than 2.0%B and lower than 0.2%C and the structures and properties of alloy after heat treatment were researched by means of optical microscopy （OM）, scanning electron microscopy （SEM）, X-ray diffraction （XRD）, hardness measurements, impact tester and pin abrasion tester. The results show that the solidification structures of cast Fe-B-C alloy consist of boride （Fe2B）, pearlite and ferrite, and boride distributes along grain boundary in network form. After normalizing at 950 ℃, the part broken network of boride in cast Fe-B-C alloy appeared, the matrix all transformed into lath martensite. The hardness of cast Fe-B-C alloy increased obviously and neared to HRC 60, its impact toughness and dynamic fracture toughness exceeded 10 J/cm^2 and 30 MPa·m^1/2, respectively. In the condition of pin-on-disk wear, cast Fe-B-C alloy showed excellent abrasion resistance. Its abrasion resistance is more excellent than that of Ni-hard white cast iron, GCr15 and Cr12MoV, nears to that of high chromium white cast iron. Cast Fe-B-C alloy has simple melting process and good casting property, does not contain costly nickel and molybdenum elements and so has low production cost.