中文摘要：

通过合理的成分设计制备了一种大热输入药芯焊丝,在实验室进行了大热输入焊接试验,研究在大热输入焊接条件下焊缝金属的组织与韧性。结果表明在热输入量为360 k J/cm大热输入焊接条件下,焊缝金属中形成了大量的细小弥散分布的夹杂物,并以夹杂物为核心诱导生成了相互交叉互锁的针状铁素体渊AF冤组织,AF晶粒间形成了大量的大角度晶界结构,是焊缝金属具有较高的冲击韧性的原因;通过进一步对夹杂物组成进行分析,发现在夹杂物周围形成了贫锰区,确定了贫锰区机制为夹杂物形成AF相变机理。

英文摘要：

A flux cored wire for high heat input was developed through rational composition design. High heat input welding experiments were done in labarory, and the microstructure and the impact toughness for large heat input weld metal were investigated. The results show that under the condition of welding heat input of 360 kJ/cm, a large number of fine inclusions are formed and distributed randomly in the weld metal, and around the inclusions, and substantial cross interlocked aeieular ferritic grains （AF microstrure） are induced. A large number of grain boundary structure with wide angles is founded between the grains,which is the reason that the weld metal can obtain high impact toughness. Through further analysis on inclusion composition, depleted Mn zone is found around inclusions, and the mechanism of depleted Mn zone is affirmed as phase transition ofinclutions to AF.