Microstructures and Toughness in Simulated Coarse Grain Heat-Affected Zones of Copper-Bearing Steel
Microstructures and toughness of simulated coarse grain heat-affected zone of hot continuously rolled copper-bearing steel were investigated using physical simulation. The results showed that brittlement is easy to happen in the region of CGHAZ with slower thermal cycles (t8/5≥45s). Granular bainite transformed from austenite led to brittlement. The dimensions of granular martensite and austenite (M-A) constituents are main factors influencing the impact toughness. There is no visible effect on the toughness when the dimensions of M-A constituents are less than 1μ m. However, the toughness decreases greatly once the dimensions exceed 1μ m. Therefore, decreasing the dimensions of M-A constituents by controlling weld heat input will do good to improve the impact toughness of copper-bearing steel.
Jitai NIU, Zuyan LIU, Cheng JIN and Guangtao Zhou
W. Y. Liu et al., "Microstructures and Toughness in Simulated Coarse Grain Heat-Affected Zones of Copper-Bearing Steel", Materials Science Forum, Vols. 575-578, pp. 910-914, 2008