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对板厚68 mm的EH40船用高强钢进行了热输入分别为382、440和450 kJ/cm的双丝气电立焊试验,借助焊接接头的拉伸试验、冲击试验、硬度测试及显微组织分析等方法,研究了热输入对EH40钢大厚板双丝气电立焊接头组织和性能的影响。结果表明,大热输入焊接主要通过控制针状铁素体形核长大、改变晶界铁素体形貌及奥氏体晶粒大小来影响EH40钢焊接接头的组织和性能。随着热输入增加,接头强度降低,热影响区软化倾向增大。热输入过大或过小都对焊缝金属韧性不利,纵观焊接接头整体力学性能的变化,在坡口角度20°、间隙8 mm条件下,其最佳的热输入为400~440 kJ/cm。
The EH40 marine high strength steel with a thickness of 68 mm was subjected to the double-wire gas-electric vertical welding test with heat input of 382,440 and 450 kJ / cm respectively. With the tensile test, impact test, hardness test and microstructure Analysis and other methods to study the heat input on the EH40 steel double-plate gas-to-wire vertical welding joint organization and performance. The results show that the heat input welding mainly affects the microstructure and properties of EH40 steel welded joint by controlling the growth of acicular ferrite nucleation and changing the ferrite morphology and austenite grain size. As the heat input increases, the strength of the joint decreases and the softening tendency of the HAZ increases. Heat input is too large or too small are tough on the toughness of the weld metal, looking at the overall mechanical properties of welded joints changes in the groove angle of 20 °, the gap 8 mm conditions, the best heat input is 400 ~ 440 kJ / cm.