Yu Tengyi, Zhou Leilei, Li Ba, Yang Ping. Effect of V Content and Heat Input on HAZ Softening Zone of Deep-sea Pipeline Steel[J]. IRON STEEL VANADIUM TITANIUM, 2020, 41(5): 159-165. doi: 10.7513/j.issn.1004-7638.2020.05.027
Citation:
Yu Tengyi, Zhou Leilei, Li Ba, Yang Ping. Effect of V Content and Heat Input on HAZ Softening Zone of Deep-sea Pipeline Steel[J]. IRON STEEL VANADIUM TITANIUM, 2020, 41(5): 159-165. doi: 10.7513/j.issn.1004-7638.2020.05.027
Yu Tengyi, Zhou Leilei, Li Ba, Yang Ping. Effect of V Content and Heat Input on HAZ Softening Zone of Deep-sea Pipeline Steel[J]. IRON STEEL VANADIUM TITANIUM, 2020, 41(5): 159-165. doi: 10.7513/j.issn.1004-7638.2020.05.027
Citation:
Yu Tengyi, Zhou Leilei, Li Ba, Yang Ping. Effect of V Content and Heat Input on HAZ Softening Zone of Deep-sea Pipeline Steel[J]. IRON STEEL VANADIUM TITANIUM, 2020, 41(5): 159-165. doi: 10.7513/j.issn.1004-7638.2020.05.027
In this paper,the welding thermal cycle process of deep-sea pipeline steel was investigated using welding thermal simulation.The microstructure variation,crystallography characteristic and second-phase precipitation behaviors of the softening zone of heat affected zone(HAZ) were characterized and analyzed by combining with the scanning electron microscope,electron back-scattered diffraction,transmission electron microscopy and hardness testing.The results show that HAZ softening zone appears in the fine-grained zone with a peak temperature of 1 000~900 ℃ for deep-sea pipeline steel whose base metal microstructure is the polygonal ferrite and acicular ferrite.Using V microalloying and low welding heat input can reduce the grain size,increase the proportion of small-angle grain boundaries and the dislocation density effectively.Thus,the softening problem of the HAZ fine-grained region can be effectively improved.