EFFECTS OF THERMAL CYCLE ON MECHANICAL PROPERTIES AND FRACTOGRAPHY IN HAZ OF HQ130 STEEL
来源期刊：Acta Metallurgica Sinica2004年第3期
论文作者：W.J.Sun B.Liu J.X.Qu
Key words：high strength steel; welding thermal cycle; heat-affected zone; impact toughness;
Abstract: The effect of different peak temperature (Tp) and cooling time (ts/5) on hardness,impact toughness and fracture morphology in the heat-affected zone (HAZ) of HQ130steel was studied by using welding thermo-simulation test. Experimental results show that the impact toughness and hardness decrease with the decrease of Tp or increase of t8/5 under the condition of a single thermal cycle. There is a brittle zone in the vicinity of Tp=800℃, where the impact toughness is considerably low. There is softened zone in vicinity of Tp=700℃, Where the hardness decreases but the toughness increases. In the practical application of multi-layer and multi-pass welding, the welding heat input should be strictly limited (t8/5≤20s) so as to reduce the softness and brittleness in the HAZ of HQ130 steel.
W.J.Sun1，B.Liu2，J.X.Qu1
(1.Department of Materials Sci. & Eng., China Univ. of Mining and Technology, Beijing 100083, China;
2.Department of Mechanical Engineering, Changsha University, Changsha 410003, China)
Abstract:The effect of different peak temperature (Tp) and cooling time (ts/5) on hardness,impact toughness and fracture morphology in the heat-affected zone (HAZ) of HQ130steel was studied by using welding thermo-simulation test. Experimental results show that the impact toughness and hardness decrease with the decrease of Tp or increase of t8/5 under the condition of a single thermal cycle. There is a brittle zone in the vicinity of Tp=800℃, where the impact toughness is considerably low. There is softened zone in vicinity of Tp=700℃, Where the hardness decreases but the toughness increases. In the practical application of multi-layer and multi-pass welding, the welding heat input should be strictly limited (t8/5≤20s) so as to reduce the softness and brittleness in the HAZ of HQ130 steel.
Key words:high strength steel; welding thermal cycle; heat-affected zone; impact toughness;
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