EFFECTS OF THE WELD THERMAL CYCLE ON MICROSTRUCTURE AND PROPERTIES OF THE HEAT-AFFECTED ZONE OF HQ130 STEEL
LI Yajiang;ZOU Zengda;CHEN Zhunian;WEI Hing(Shandong Polytechnic University; Jinan 250014); JIANG Quanchang(Engineering Machinery Co. Ltd. Xiamen361004)(Manuscript received 1995-10-04)
Cite this article:
LI Yajiang;ZOU Zengda;CHEN Zhunian;WEI Hing(Shandong Polytechnic University; Jinan 250014); JIANG Quanchang(Engineering Machinery Co. Ltd. Xiamen361004)(Manuscript received 1995-10-04). EFFECTS OF THE WELD THERMAL CYCLE ON MICROSTRUCTURE AND PROPERTIES OF THE HEAT-AFFECTED ZONE OF HQ130 STEEL. Acta Metall Sin, 1996, 32(5): 532-537.
Abstract The effects of the different peak temperatures(T_m) and cooling times(t) on the microstructure, hardness, impact toughness and fracture morphology of heat-affected zone(HAZ) of HQ130 steel were investigated by means of the weld thermo-simulation test.Experimental results indieated that the impact toughness and hardness were decreased with the decrease in T_m or increase in cooling time under the condition of single thermal cycle. There was brittle zone in the vicinity of T_m = 800℃ . where the impact toughness was obviously lower, and softened zone in 700℃, where the hardness obviously decreased but toughness increased. In practicalwelding, the multi-layer and multi-pass welding, in which the welding heat input was strictly limited (t≤20 s), should be applied to reduce softness and brittleness in HAZ of HQ130 steel.
