摘要
采用自行研究开发的一种新型药芯焊丝,通过实验室大热输入焊接实验,研究分析了热输入量对焊缝熔敷金属组织与冲击韧性的影响规律.结果表明:在大热输入焊接条件下,熔敷金属中形成了大量细小、弥散分布的夹杂物,夹杂物周围诱导生成的大量相互交叉互锁的针状铁素体晶粒,这是焊缝熔敷金属具有较高低温冲击韧性的主要原因;随着焊接热输入量的增加,尺寸为1μm以下的夹杂物数量减少,1μm以上夹杂物分布无显著变化,针状铁素体形核点减少,熔敷金属中针状铁素体晶粒尺寸略有增加、低温冲击韧性略有降低.
In recent years, the components tend to be large-scale and large-span. In order to improve the welding construction efficiency and reduce production costs, the high input welding methods, such as automatic gas electric vertical welding, submerged arc welding, electro slag welding, etc., have been widely used in manufacturing fields, like shipbuilding, buildings, bridges, petrochemical and marine structures, etc,. The domestic iron and steel enterprises and research institutes have cooperated successively to develop a number of heat input welding steel with heat input greater than 400 kJ/cm. However, at present, the welding materials which can be matched with these special steels are still dependent on import. In order to change this passive situation, a new type of flux cored wire has been independently developed in this research. The effects of heat input on the microstructure and impact toughness of the weld metal have been investigated through laboratory tests. The results demonstrate that under the condition of large heat input welding, a large number of fine inclusions are formed and distributed randomly in the weld metal. Substantial amount of interlocked acicular ferritic grains are found around the inclusions, contributing to the high impact toughness for the weld metal. With the increase of heat input value, the number of fine inclusions （smaller than 1 gin） decreases and the tendency of inclusion assembly and growth is found to accelerate. Simultaneously, the nucleation points of acicular ferrite decreased and the grain size of acicular ferrite increased slightly in the weld metal. The impact toughness was deteriorated mildly as well.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2016年第7期890-896,共7页
Acta Metallurgica Sinica
基金
国家自然科学基金资助项目51174058~~
关键词
焊缝金属
大热输入
针状铁素体
韧性
weld metal, high heat input, acicular ferrite, toughness
