Transactions of Materials and Heat Treatment

Title：Under-cooled austenite phase transformation rules and design of cooling process for steel 22CrMoB

Authors： Chen Tao Chen Yadi

Unit： Hebei College of Industry and Technology Lanzhou University

KeyWords： under-cooled austenite CCT curve banded microstructure phase transformation rules steel 22CrMoB cooling process

ClassificationCode：TG142.1

year,vol(issue):pagenumber：2017,42(10):189-194

Abstract：

By dilatometer DIL 805A with microstructure and hardness measurement, the critical temperatures of steel 22CrMoB was determined, and its continuous cooling transformation (CCT) curve of under-cooled austenite was obtained. Then, the transformation rules of continuous cooling process for undercooled austenite were studied. At last, the deformation temperature and cooling temperature after deformation were designed according to CCT curve and field data of the steel, and the precipitation behaviors of the banded microstructure and widmanstatten microstructure of steel 22CrMoB were studied after deformation and cooling. The results show that the Ac1 and Ac3 temperatures of steel 22CrMoB is 730 ℃ and 840 ℃ respectively, its critical cooling rate is recommended at 50 ℃·s-1 and the hardenability is increased comparing to steel 22CrMo before adding element B. Thus, its ideal deformation and cooling parameters are obtained with the deformation temperature of 940-980 ℃ and the cooling rate of 0.6-0.9 ℃·s-1. Furthermore, the ferrite and pearlite of fine and uniform grains are precipitated without the banded microstructure and widmanstatten microstructure.

Funds：

河北省科技计划项目（15211031）；河北工业职业技术学院应用研发中心项目（2015YF01）

陈涛（1970-），男，硕士，副教授，E-mail：chtao8888@163.com

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