Effect of Heat Imput on Microstructure and Toughness of High Strength Bridge Steel
The coarse grain heat affected zone(CGHAZ) at different parameters t8/5 of high-strength bridge steel Q460q were simulated with thermal simulation machine. the microstructure of CGHAZ and the effect of granular bainite on the toughness were analyzed in this paper.The results show that: When t8/5<60s, lath bainite and granular bainite intertwine, and the quantity of strip M-A constituents in granular bainite decreased, so toughness is higher.When t8/5>60s, the quantity of eutectoid ferrite and granular bainite increased, coarse M-A constituent resulting in the grain size of effective crack propagation becoming coarser and toughness decreased significantly.
Jianmin Zeng, Taosen Li, Shaojian Ma, Zhengyi Jiang and Daoguo Yang
K. N. Jia "Effect of Heat Imput on Microstructure and Toughness of High Strength Bridge Steel", Advanced Materials Research, Vols. 194-196, pp. 255-258, 2011