Study on Post Weld Heat Treatment and Microstructure & Properties of Cast Die Steel
Author of the article:GONG Houxian;WEI Ying
Author's Workplace：Department of Automotive Engineering,Chuzhou Vocational and Technical College,Chuzhou 239000,China;School ofMaterials Science and Engineering,Hefei University of Technology,Hefei 230009,China
Key Words：cast die steel welding heat treatment microstructure properties
Abstract：
The effect of welding current on the forming and mechanical properties of quenched and tempered cast die steel welded joint was studied, microstructure and mechanical properties of welded joint of welded and tempered state were compared analyzed. The results show that when the welding current is 90~110 A, there will be no interruption or splash in the welding process, and no obvious slag inclusion in the weld, and the weld joint has good welds formability. The tempering treatment at 500 ℃ for 2 h has a significant improvement on the microstructure of the welding zone and quenching zone, but little influence on the structure of the base material and the tempering zone. The quenching zone of tempered welded joint is tempered martensite, the welding zone is tempered martensite, ferrite and a small amount of retained austenite, and the tensile strength of the welded joint can be improved obviously after welding, but the fracture position will not change;When the welding current is 90~110 A, the tensile strength of welded joint and tempered welded joint is higher than that of welding current of 110~140 A. When the welding current is 90~110 A, the tensile strength of the tempered welded joint can reach 81.4% of the cast die steel.
