摘要
采用微量稀土La-Ce微合金化对高锰铸钢进行变质处理,借助金相显微镜、扫描电镜、能谱仪、冲击试验机、显微硬度计等检测手段,研究了La-Ce混合稀土对铸造高锰钢显微组织、夹杂物和力学性能影响.结果表明:微量的稀土La-Ce使高锰钢铸态组织柱状晶区缩短,等轴晶区扩大,二次枝晶间距减小,晶界碳化物细化;同时钢中夹杂物变性,由原来多边形的TiN、Al2O3与MnS复合夹杂转变为椭球状或球状的含稀土复合夹杂.稀土La-Ce改善了铸态高锰钢的冲击韧性及显微硬度,在0℃、-20℃、-40℃试验温度下横向冲击功分别提升32.3%、67.5%,170.0%,低温韧性提升更加显著;显微硬度HV10由221提升至238.
Abstract
The effect of La-Ce mixed rare earth elements on the microstructure,inclusions,and mechanical properties of cast high manganese steel was studied by using trace rare earth La-Ce microalloyed high manganese cast steel for modification treatment,and detection methods such as metallographic microscope,scanning electron microscope,energy dispersive spectrometer,impact testing machine,and microhardness tester.The results show that a trace amount of rare earth La-Ce shortens the columnar crystal zone,expands the equiaxed crystal zone,reduces the secondary dendrite spacing,and refines the grain boundary carbides in the as-cast structure of high manganese steel.At the same time,the inclusions in the steel undergo denaturation,transforming from polygonal TiN,Al2O3,and MnS composite inclusions into ellipsoidal or spherical rare earth containing composite inclusions.Rare earth La-Ce improves the impact toughness and microhardness of as cast high manganese steel.The transverse impact energy increases by 32.3%,67.5%,and 170.0%respectively at 0℃,-20℃,and-40℃test temperatures,and the low-temperature toughness improvement is more significant.The microhardness HV10 has been increased from 221 to 238.
维普
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