TWI Industrial Member Report Summary 253/1984
By P L Threadgill and R H Leggatt
As part of a more wide ranging study on the effects of postweld heat treatment (PWHT) on the mechanical properties and residual stress levels of steels, a study has been made of the effects of time, temperature, and repeated PWHT cycles on the strength, toughness and residual stress levels in a continuously cast C-Mn-Nb-Al steel. It has been found that temperature has a more significant effect on properties than time for all parameters. Degradation of properties with increasing time and temperature seems more rapid in the HAZ at the plate mid-thickness than elsewhere. In general, excellent HAZ toughness results have been obtained with only occasional low values. A major factor is, no doubt, the very low fraction of coarse-grained HAZ microstructure resulting from the welding procedure used.