Laser welding is widely used for the on-line joining of hot-rolled steel strips for hot stamped steel by steel plants recently. However, the high breaking rate caused by the emergence of hard martensite in weld was a fatal disadvantage. In this paper, the welded joints of hot-rolled strips for 1500 MPa grade hot stamped steel were made through laser filler wire welding and laser welding, and a series of PWHT experiments were further conducted on laser welding joints. The influence of filler wire and PWHT on the microstructure and mechanical performance of welded joints was analyzed. The results showed that weld appearance was refined by wire filling process, while the microstructure of weld was martensite and cupping test results could not meet the requirements still. As for welded joints with PWHT, the microstructure and mechanical performance were not refined when the PWHT temperature was 500 °C. But the cupping test results were much better at 600 °C and 800 °Ccompared with the as welded states, accordingly, the weld metal microstructure was tempered martensite and ferrite.
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