Heat Treatment of Metals ›› 2024, Vol. 49 ›› Issue (7): 249-253.DOI: 10.13251/j.issn.0254-6051.2024.07.038

• PROCESS RESEARCH • Previous Articles     Next Articles

Effect of normalizing temperature on microstructure and mechanical properties of 36MnVS4 and 46MnVS5 steels for fracture splitting connecting rod

Lu Mingxia, Zhang Lei, Wang Xinshe   

  1. Jiangyin Xingcheng Special Steel Co., Ltd., Jiangyin Jiangsu 214429, China
  • Received:2024-01-30 Revised:2024-04-26 Online:2024-07-25 Published:2024-08-29

Abstract: Mechanical properties and microstructure evolution of two medium carbon non-quenched and tempered steels 36MnVS4 and 46MnVS5 widely used for automotive fracture splitting connecting rod at different normalizing temperatures were compared and studied, and the strengthening mechanism was analyzed. The results show that with the increase of normalizing temperature, the yield strength, tensile strength and hardness of both the 36MnVS4 and 46MnVS5 steels increase gradually, and the tensile strength and hardness of the 46MnVS5 steel are higher than those of the 36MnVS4 steel. When normalized below 990 ℃, the yield strength of the 46MnVS5 steel is higher than that of the 36MnVS4 steel, while normalized above 990 ℃, the yield strength of the 46MnVS5 steel is lower. When normalized above 1140 ℃, the elongation and percentage reduction of area of the 36MnVS4 steel are higher than that of the 46MnVS5 steel, and the toughness is better. The difference in mechanical properties between the two steels is mainly due to both the content of proeutectoid ferrite and the precipitated strengthening phase V(C, N) in proeutectoid ferrite after normalizing at 1200 ℃ of the 36MnVS4 steel are more than that in 46MnVS5 steel, so the plasticity of 36MnVS4 steel is better. However, considering the production process and properties requirements of the fracture splitting connecting rod, the improvement of toughness is unfavorable to the fracture splitting processing of the connecting rod, and the 46MnVS5 steel has good comprehensive mechanical properties and more cost advantages than the 36MnVS4 steel. Therefore, the 46MnVS5 steel is better to be selected for the fracture splitting connecting rod.

Key words: fracture splitting connecting rod, 36MnVS4 steel, 46MnVS5 steel, normalizing temperature, mechanical properties, proeutectoid ferrite

CLC Number: