Effect of carbon content and sintering temperature on microstructure and mechanical properties of MIM 4340 alloy steel
XU Ting1, HE Hao2, LOU Jia3, LI Yimin1,2, YIN Jian1, LIU Chen2, QIN Jianchun2
1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China; 2. Research Center of Materials Science and Engineering,Guangxi University of Science and Technology, Liuzhou 545006, China; 3. School of Materials Science and Engineering, Xiangtan University, Xiangtan 411105, China
Abstract：4340 low alloy steel was prepared by injection molding process. The effects of carbon contents, sintering temperature and heat treatment process on microstructure and mechanical properties were studied. The results show that the powders with different carbon contents can be prepared by adding CN/OM iron powders. After sintering at 1 280-1 320 ℃ for 2 h, the sample (mass fraction of 0.50% carbon content in raw powders) is closest to the standard carbon content. The density decreases first and then increased with the increase of carbon contents, and the density increases with the increase of sintering temperature. The microstructure consists of ferrite (α-Fe), pearlite (ferrite+cementite Fe3C) and bainite. The tensile strength and elongation are 762.16 MPa to 1032.03 MPa and 5.25% to 8.62%, respectively. The best mechanical properties are obtained after oil quenching at 850 ℃ for 0.5 hour and tempering at 400 ℃ for 2 h. The tensile strength and elongation reaches to 1 510.24 MPa and 4.30%, respectively, and the hardness is 40.0 HRC.
许婷, 何浩, 娄嘉, 李益民, 尹健, 刘晨, 秦健春. 碳含量及烧结温度对MIM 4340合金钢组织及力学性能的影响[J]. 粉末冶金材料科学与工程, 2019, 24(6): 563-570.
XU Ting, HE Hao, LOU Jia, LI Yimin, YIN Jian, LIU Chen, QIN Jianchun. Effect of carbon content and sintering temperature on microstructure and mechanical properties of MIM 4340 alloy steel. Materials Science and Engineering of Powder Metallurgy, 2019, 24(6): 563-570.
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2019, Vol. 24 
