%A ZHAO Fan, HU Hao, LIU Yazheng, ZHANG Zhihao, XIE Jianxin %T Annealing Condition Control Based on the Evolution of Complex Microstructure and Surface Decarburization in 23MnNiMoCr54 Steel %0 Journal Article %D 2022 %J Materials Reports %R 10.11896/cldb.20100217 %P 20100217-6 %V 36 %N 1 %U {http://www.mater-rep.com/CN/abstract/article_4591.shtml} %8 2022-01-10 %X The microstructure characteristics and surface decarburization are crucial to the quality control of high strength mining round-link chain steel 23MnNiMoCr54 and have an important effect on the subsequent bending, welding, heat treatment, prestretching processes and service performance of mining round-link chains. This paper reported the effect of annealing temperature and atmosphere on harndess, microstructure and surface decarburization of 23MnNiMoCr54 rolled bars. After annealing in temperature range of 660—710 ℃, the martensite and bainite transform into tempered sorbite and annealed bainite, respectively. The spheroidization degree of carbide is improved, and the hardness of rolled bar decreases significantly. In addition, with the increase of annealing temperature, the hardness of rolled bar also decreases. After annealing in temperature range of 720—730 ℃, the abnormal microstructure is composed of coarse martensite, ferrite and a small amount of carbides, resulting in a relatively high hardness of rolled bar. In the meanwhile, with the annealing temperature increasing from 660 ℃ to 730 ℃, the surface decarburization depth increases with a sudden increasing at 700 ℃. With the oxygen concentration decreasing from 21% to about 0%, the surface decarburization depth after annealed at 710 ℃ decreases significantly. When the oxygen concentration is below 5.25%, the surface decarburization at straight edge is eliminated. The annealing temperature of 23MnNiMoCr54 rolled bars should be controlled in the temperature range of 680—700 ℃. In order to reduce the surface decarburization as much as possible, the oxygen concentration should be controlled below 5%.