硼对耐磨球墨铸铁组织和力学性能的影响

研究了不同硼含量对含碳3．4％－3．8％、含硅2．0％－3．0％，含锰2．0％－＝3．0％的球墨铸铁铸主热处理态组织和力学性能的影响。结果表明：随着硼含量的增加，铸态组织中的碳化物数量增加，硬度提高，冲击韧性下降，当硼含量大于0．010％时，铸态组织中出现了明显的网状或断网状碳化物，冲击韧性下降幅度较大，经淬火、回火后、碳化物发生不同程度的溶解。当硼含量为0．003％－0．0105时，热处理后碳化物基本消失，硬度保持在HRC50左右，冲击韧性达到或超过9J／cm^2；当硼含量超过0．010％时，热处理后仍存在断网状或条块状碳化物，硬度稍有增加，冲击初性明显下降。

Influence of Boron on Microstructure and Mechani cal Properties of Abrasive Wear Resistant Ductile Cast Iron

The influence of boron on micros tructure and mechanical properties of ductile cast iron with C 3.4 %～3.8 %, Si 2.0 %～3.0 % and Mn 2.0 %～3.0 % has been studied.The results indicated that th e amount of the carbide in the as cast microstructure increases as the boron con tent increases.At the same time, the hardness rises and the impact toughness de clines.When boron content surpasses 0.010 %, there is some clear continuous car bide network or discontinuous carbide network in the microstructure, as a result , the impact toughness declines greatly.After heat treated by quenching and tem pering, the carbide in the cast microstructure decomposes more or less.When the boron content is controlled between 0.003 % and 0.010 %, the carbide in the hea t-treated samples generally disappears, and the hardness keeps about HRC 50, an d the impact toughness comes up to or surpasses 9 J/cm2.However, when boron c ontent surpasses 0.010 %, some discontinuous carbide network or carbide blocks e xist, thus the hardness rises slightly, at the same time, the impact toughness declines obviously.