大线能量低焊接裂纹敏感性压力容器用钢的性能

Development of Large Heat Input Welding Steel with Low Susceptibility to Weld Cold Cracking for Pressure Vessels

研制了一种大线能量低焊接裂纹敏感性压力容器用钢,研究了其力学性能、微观组织结构和焊接粗晶热影响区(CGHAZ)的微观组织结构特征及力学性能。结果表明:研制的新钢种集高强度(σs≥490MPa、σb≥610MPa)、高韧度(-20℃,Akv≥47J)、优异的焊接性能于一体,能够承受大线能量焊接(50kJ/cm),并具有低焊接裂纹敏感性。OGHAZ中弥散分布稳定的复合氧化物夹杂物促使针状铁素体的形成,针状铁素体的数量与输入线能量有关并显著影响CGHAZ的力学性能。

A new low alloying steel with low susceptibility to weld cold cracking has been developed for large heat input welding in pressure vessel engineering. The microstructure feature of base steel and weld HAZ has been investigated The developed steel exhibited high strength (σs≥490 MPa、σb≥610 MPa), high impact toughness ( - 20 ℃,Akv≥47 J) and excellent weldability. The complex inclusions containing oxides in HAZ promoted the acicular ferrite formation in weld thermal cycle. The acicular ferrite formed in HAZ was a function of heat input and affected the mechanical properties of HAZ.