淬火温度对轧辊用高硼铁基合金组织和力学性能的影响

采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)、摆锤式冲击试验机和维氏硬度计等研究了淬火温度对高硼铁基合金轧辊材料组织和力学性能的影响。结果表明:高硼铁基合金淬火态基体组织为马氏体,基体中鱼骨状(M₂(B,C))、层片状(M₂C)、长条状(M₃(B,C))和颗粒状(M(B,C))等形态的硼碳化物呈断开趋势。与铸态组织相比,其中层片状硼碳化物的变化最为明显,其形态由致密粗大的连续状转变为松散细小的颗粒状,减小了对基体的割裂作用;高硼铁基合金淬火组织中硼碳化物的类型未发生变化,但是其析出量随淬火温度的升高而减少。高硼铁基合金淬火态硬度和冲击性能较铸态明显提高,其基体硬度和冲击性能随淬火温度的升高而增加,而宏观硬度随淬火温度的升高呈现出先增加后降低的趋势;淬火温度为1050 ℃的宏观硬度最大,为63.1 HRC,淬火温度为1150 ℃的冲击吸收能量最大,为10.9 J。

Effect of quenching temperature on microstructure and mechanical properties of high-boron Fe-based alloy for roll

Effect of quenching temperature on the microstructure and mechanical properties of high-boron Fe-based alloy for roll was studied by means of optical microscope (OM), scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), pendulum impact tester and Vickers hardness tester. The results show that the hardened matrix of high-boron Fe-based alloy is martensite, while the boron carbides in the matrix, such as fishbone (M₂(B, C)), lamellar (M₂C), long (M₃(B,C)) and granular (M(B,C)), are tending to be disconnected. Compared to the as-cast, among them the change of lamellar boron carbide is the most obvious, and its morphology changes from the dense and coarse continuous to loose and fine granular, which reduces the fragmentation of matrix. The type of boron carbides in the quenched structure of high-boron Fe-based alloy does not change, but the amount of precipitation decreases with the increase of quenching temperature. The hardness and impact property of the as-quenched high-boron Fe-based alloy are obviously higher than that of the as cast. The hardness and impact property of the matrix increase with the increase of the quenching temperature, while the macro-hardness increases first and then decreases with the increase of quenching temperature. Macro-hardness of the specimen quenched at 1050 ℃ reaches the maximum value of 63.1 HRC, while the maximum value of impact absorbed energy is 10.9 J, when quenched at 1150 ℃.