工程科学学报，第40卷，第5期：579-586.2018年5月 Chinese Journal of Engineering,Vol.40,No.5:579-586,May 2018 DOI:10.13374/j.issn2095-9389.2018.05.008;http://journals.ustb.edu.cn 模锻变形对曲轴用非调质钢1538MV显微组织的影响 杨 勇12)四，周乐育2)，蒋鹏2)，任学平”，贺小毛2) 1)北京科技大学材料科学与工程学院，北京1000832)北京机电研究所有限公司锻压技术中心，北京100083 ☒通信作者，E-mail:y19821110@163.com 摘要影响曲轴锻后组织的主要因素有变形量，终锻温度，金属流动及锻后冷却.本文采用数值模拟的方法研究了曲轴用 非调质钢1538MV的锻造过程，并对轧材原料和曲轴成品的显微组织进行了分析，探讨了模锻变形对曲轴显微组织的影响. 研究结果表明，曲轴较高的锻造温度和较小的变形量使得曲轴的锻后组织较轧材有所粗化.曲轴变形过程中的温度和应变分 布不均导致了曲轴组织的不均匀.曲轴的铁素体含量和珠光体片层间距都低于轧材，且部分位置出现了贝氏体组织，这说明 曲轴锻后的相变区冷速过快，应当进一步优化曲轴锻后冷却制度.另外，曲轴锻造过程中的偏析区金属流动对曲轴的锻后组 织产生了明显的影响，也是造成贝氏体组织产生的原因，应严格控制轧材的质量.研究结果为轧材质量的提升和曲轴锻造工 艺及锻后冷却制度的优化指明了方向。 关键词非调质钢：曲轴：模锻：显微组织：数值模拟 分类号TG142.21 Influence of die-forging deformation on microstructure of 1538MV non-quenched and tempered steel for crankshaft YANG Yong2),ZHOU Le-yu2),JIANG Peng?,REN Xue-ping,HE Xiao-mao) 1)School of Materials Science and Engineering,University of Seience and Technology Beijing,Beijing 100083,China 2)Forging Technology Center,Beijing Research Institute of Mechanical Electrical Technology,Beijing 100083,China Corresponding author,E-mail:yy19821110@163.com ABSTRACT Non-quenched and tempered steels offer many advantages such as energy saving,emission reduction,simple process- ing,short production time,and low cost.Demand for energy saving and emission reduction is increasing with the rapid increase of car production and ownership.As a result,the usage of non-quenched and tempered steel in automotive parts has attracted increasing at- tention.The main problem with non-quenched and tempered steel in actual production is the lack of a hot deformation process and a cooling process that can be used to precisely control the microstructure and properties of the material.The material 1538MV is a type of pearlite +ferrite non-quenched and tempered steel,and its use for building crankshafts has not been studied sufficiently thus far.The main factors affecting the structure of a crankshaft are deformation,final forging temperature,and metal flow and cooling after forging. In this paper,the forging process of 1538MV non-quenched and tempered steel for building a crankshaft was studied by means of nu- merical simulation,microstructures of the rolled material and finished crankshaft were analyzed,and influence of deformation on the microstructure of the crankshaft was discussed.The results show that the microstructure of a crankshaft forged at a higher temperature and with smaller deformation is coarser than that of a crankshaft made of rolled material.The inhomogeneity of the microstructure is caused by unevenness of temperature and strain distribution during crankshaft deformation.The ferrite content of the crankshaft and the pitch of the pearlite were lower than those of the rolled material,and the bainite structure appeared in a few parts,which indicated that the cooling rate was too fast during phase transformation.Therefore,the cooling process should be optimized further.In addition,the metal flow in the segregation zone during the crankshaft forging process significantly influences the forged microstructure of the crank- 收稿日期：2017-10-17工程科学学报,第 40 卷,第 5 期:579鄄鄄586,2018 年 5 月 Chinese Journal of Engineering, Vol. 40, No. 5: 579鄄鄄586, May 2018 DOI: 10. 13374 / j. issn2095鄄鄄9389. 2018. 05. 008; http: / / journals. ustb. edu. cn 模锻变形对曲轴用非调质钢 1538MV 显微组织的影响 杨 勇1,2) 苣 , 周乐育2) , 蒋 鹏2) , 任学平1) , 贺小毛2) 1) 北京科技大学材料科学与工程学院, 北京 100083 2) 北京机电研究所有限公司锻压技术中心,北京 100083 苣 通信作者, E鄄mail:yy19821110@ 163. com 摘 要 影响曲轴锻后组织的主要因素有变形量、终锻温度、金属流动及锻后冷却. 本文采用数值模拟的方法研究了曲轴用 非调质钢 1538MV 的锻造过程,并对轧材原料和曲轴成品的显微组织进行了分析,探讨了模锻变形对曲轴显微组织的影响. 研究结果表明,曲轴较高的锻造温度和较小的变形量使得曲轴的锻后组织较轧材有所粗化. 曲轴变形过程中的温度和应变分 布不均导致了曲轴组织的不均匀. 曲轴的铁素体含量和珠光体片层间距都低于轧材,且部分位置出现了贝氏体组织,这说明 曲轴锻后的相变区冷速过快,应当进一步优化曲轴锻后冷却制度. 另外,曲轴锻造过程中的偏析区金属流动对曲轴的锻后组 织产生了明显的影响,也是造成贝氏体组织产生的原因,应严格控制轧材的质量. 研究结果为轧材质量的提升和曲轴锻造工 艺及锻后冷却制度的优化指明了方向. 关键词 非调质钢; 曲轴; 模锻; 显微组织; 数值模拟 分类号 TG142郾 21 收稿日期: 2017鄄鄄10鄄鄄17 Influence of die鄄forging deformation on microstructure of 1538MV non鄄quenched and tempered steel for crankshaft YANG Yong 1,2) 苣 , ZHOU Le鄄yu 2) , JIANG Peng 2) , REN Xue鄄ping 1) , HE Xiao鄄mao 2) 1) School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, China 2) Forging Technology Center, Beijing Research Institute of Mechanical & Electrical Technology, Beijing 100083, China 苣 Corresponding author, E鄄mail: yy19821110@ 163. com ABSTRACT Non鄄quenched and tempered steels offer many advantages such as energy saving, emission reduction, simple process鄄 ing, short production time, and low cost. Demand for energy saving and emission reduction is increasing with the rapid increase of car production and ownership. As a result, the usage of non鄄quenched and tempered steel in automotive parts has attracted increasing at鄄 tention. The main problem with non鄄quenched and tempered steel in actual production is the lack of a hot deformation process and a cooling process that can be used to precisely control the microstructure and properties of the material. The material 1538MV is a type of pearlite + ferrite non鄄quenched and tempered steel, and its use for building crankshafts has not been studied sufficiently thus far. The main factors affecting the structure of a crankshaft are deformation, final forging temperature, and metal flow and cooling after forging. In this paper, the forging process of 1538MV non鄄quenched and tempered steel for building a crankshaft was studied by means of nu鄄 merical simulation, microstructures of the rolled material and finished crankshaft were analyzed, and influence of deformation on the microstructure of the crankshaft was discussed. The results show that the microstructure of a crankshaft forged at a higher temperature and with smaller deformation is coarser than that of a crankshaft made of rolled material. The inhomogeneity of the microstructure is caused by unevenness of temperature and strain distribution during crankshaft deformation. The ferrite content of the crankshaft and the pitch of the pearlite were lower than those of the rolled material, and the bainite structure appeared in a few parts, which indicated that the cooling rate was too fast during phase transformation. Therefore, the cooling process should be optimized further. In addition, the metal flow in the segregation zone during the crankshaft forging process significantly influences the forged microstructure of the crank鄄