一、序言高度可靠的近代工程结构要求焊缝金属具有良好的断裂韧性。迄今表明,C-Mn钢和低合金高强度钢焊件的韧性由焊缝金属的组织所决定。另一方面,对低合金高强度钢采用多道焊,以减轻高热输入量焊接时HAZ的脆化。众所周知,在这种情况下,各道焊道随后 First, the preface A highly reliable modern engineering structure requires weld metal with good fracture toughness. It has so far been shown that the toughness of weld metal in C-Mn steels and low alloy high strength steels is determined by the microstructure of the weld metal. On the other hand, multi-pass welding of low-alloy high-strength steel to reduce HAZ embrittlement during high heat input welding. As we all know, in this case, each weld bead subsequently