研究了焊接热输入对WEL-TEN780A高强钢热影响区(HAZ)断裂性能的影响。结果表明,通过控制焊接热输入可以获得理想的焊接热影响区断裂性能。控制焊接热输入使得t_(8/5)为10～25s时,CTOD断裂韧性值均大于0.25mm,其断口呈韧窝状;而t_(8/5)等于30s时,CTOD值有所下降,最小值低于0.25mm,试样断口呈解理状;过热区组织粗大,原奥氏体晶界有MA组织析出。采用较小的焊接热输入和较快的冷却速度,有利于提高该类钢焊接接头抵抗脆断的能力。 The effect of welding heat input on the fracture properties of HAZ in WEL-TEN780A high-strength steel was studied. The results show that the ideal weld HAZ fracture properties can be obtained by controlling the welding heat input. The CTOD fracture toughness value is greater than 0.25mm when t_ (8/5) is 10 ~ 25s, and the fracture is ductile. When t_ (8/5) is equal to 30s, the CTOD value decreases, The minimum value is less than 0.25mm, the sample fracture was cleaved; superheated zone coarse, austenite grain boundary MA tissue precipitation. The use of smaller heat input and faster cooling rate of the welding is beneficial to improve the ability of the welded joint of this kind of steel to resist brittle fracture.