Study on Microstructure and Low-Temperature Impact Toughness in Coarse Grain Heat-Affected Zone of EH460 Steel

Herein, the effects of peak temperature on the microstructure and low-temperature impact toughness of coarse grain heat-affected zone (CGHAZ) of EH460 steel are investigated by Gleeble simulation welding. The low-temperature impact toughness of CGHAZ decreases with the increase of peak temperature. With the increase of peak temperature, the microstructure of CGHAZ gradually changes from bainite to a mixed structure composed of bainite, intragranular ferrite, side lath ferrite, and a small amount of grain boundary ferrite. The inclusions size decreases as the peak temperature increases. The existence of large-sized inclusions is conducive to the initiation and propagation of cracks, reducing the low-temperature impact toughness of the material. Herein, the effect of peak temperature on the microstructure and low-temperature impact toughness of coarse grain heat-affected zone (CGHAZ) is investigated by Gleeble simulation welding. As the peak temperature increases, the microstructure changes from bainite to mixed structure, the grain size increases and the inclusions size decreases (all diameters are greater than 3 mu m), which reducing the low-temperature impact toughness.image (c) 2024 WILEY-VCH GmbH