回火温度对960 MPa级工程机械用钢组织及析出相的影响
Effect of Tempering Temperature on Microstructure and Precipitate of 960 MPa Engineering Machinery Steel
张之胜, 徐荣杰, 严平沅, 张 涛
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作者单位：鞍钢股份有限公司 技术中心, 辽宁 鞍山 114009
中文关键字：回火温度； 合金渗碳体； 析出相； 再结晶
英文关键字：tempering temperature; alloyed cementite; precipitates; recrystallization
中文摘要：采用透射电子显微镜研究了960 MPa级工程机械用钢淬火及不同温度回火后显微组织及析出相的变化规律。结果表明：920 ℃淬火后，显微组织以板条马氏体为主，还有极少量孪晶马氏体，马氏体发生自回火现象。在400 ℃以下回火，(Ti，Nb)(C，N)尺寸和数量没有明显变化。500 ℃回火后，在晶界和亚晶界开始析出(Fe、Mn、Cr)3C合金渗碳体。600 ℃回火后，在晶内和晶界析出(Fe，Mn，Cr，Ni，Mo，V)3C合金渗碳体，Mo2C大量析出。650 ℃回火后，VC大量析出，发生再结晶，开始多边形化。
英文摘要：Microstructure and change rules of precipitates of 960 MPa engineering machinery steel were studied by TEM after quenching and tempering. The results show that the microstructure is main lath martensite and a few twinned martensites after quenching at 920 ℃ and self tempering martensite occurred. After tempering below 400 ℃, the size and quantity of (Nb, Ti)(C, N) didn't vary obviously. After tempering at 500 ℃, (Fe, Mn, Cr)3C is precipitated near grain boundaries and subgrain boundaries. After tempering at 600 ℃, (Fe, Mn,Cr, Ni, Mo, V)3C is precipitated in grains and near grain boundaries. At the same time, Mo2C is precipitated in quantities. After tempering at 650 ℃,VC is precipitated in quantities. The recrystallization happenes and polygonal ferrites begin to form.