Effect of cooling process on microstructure and properties of low alloy abrasion resistance steel NM400
LIANG Liang1，2，XU De-qiang2， LIU Xu-hui2， LI Guo-cang2， DENG Xiang-tao1，HUANG Long1
1.State Key Laboratory of Rolling Technology and Automation，Northeastern University，Shenyang 110819，China
2.Hunan Valin Lianyuan Iron and Steel Co.，Ltd.，Loudi 417009，China
Abstract：The mechanical property and microstructure of two kinds of low alloy abrasion resistance steel plates NM400 and the evolution of the microstructure and precipitates under two cooling conditions（Front stage central cooling and Sparse cooling）were investigated byusing SANSCMT5105 electronic universal testing machine，HV9250 instrument-ed drop hammer impact testing machine，optical microscope（OM）and scanning electron microscope（SEM）.The results showed that the microstructure of the two cooling processes is dominated by granular bainite.The content of bainite and the size of the precipitates in the slabs under rapid cooling conditions are relatively large.For the slow cooling，there is a certain amount of pro-eutectoid ferrite，and the size of precipitates is also small. Under the rapid cooling condition，the tensile strength of NM400 is higher，reaching 637.5 MPa，and under the slow cooling condition，the low-temperature impactenergy of NM400 at－20℃ is higher，reaching 167J.
2019, Vol. 37 
