摘要
应用微合金化铸铁同质焊条,采用小电流打底、大电流连续焊工艺,研究了预热温度与焊缝组织及性能之间的相关性。结果表明,微合金化铸铁焊条石墨化能力强,焊缝白口倾向小;小电流打底、大电流连续焊工艺可有效地减小熔深,在很大程度上抑制了熔合区白口的产生。微合金化铸铁焊条可实现常温焊接。预热温度小于200℃即可获得组织和性能与母材一致的同质焊缝。随着焊件预热温度的升高,焊缝中的石墨形态由细小的点状逐渐向菊花状、片状过渡,铁素体含量增多,焊缝硬度减小。焊件预热至200℃所获得的焊缝组织由珠光体、铁素体和细片状石墨及菊花状石墨组成,熔合区则由珠光体、少量碎块状铁素体及过冷石墨片组成,接头力学性能良好。
Using a micro-alloying cast iron electrode the relationship between preheat temperature and microstructure and properties of joint were investigated by backing welding with low-current and then continuous welding with high-current. The results showed that the micro-alloying cast iron electrode has strong graphitizing ability and the weld metal had a little chilling tendency. The applied welding process can effectively decrease the depth of fusion zone and suppress the precipitation of cementite in fusion zone at a great extent. Thus the welding with the micro-alloying cast iron electrode can be realize at ambient temperature. When the preheated temperature is less than 200 ℃, the homogeneous weld can be obtained which has the same microstructure and properties as base metal. With the increase of the preheat temperature, the graphite morphology in weld changes from spotted graphite to rosette graphite to flake graphite. The contents of graphite and ferrite increase, while the hardness of the weld decreases. If the preheated temperature reaches to 200 ℃, the microstructure of the weld consists of pearlite, ferrite, flaky graphite and rosette graphite, and the microstructure of fusion zone consists of pearlite, small shiver ferrite and undercooled graphite. The welded joint has excellent mechamical properties.
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2007年第10期53-56,共4页
Transactions of The China Welding Institution
基金
陕西省教育厅科学研究计划资助项目(07JK351)
西安市科技攻关计划资助项目(GG06069)
2006年西安市青年科技人才创业计划资助项目
关键词
微合金化铸铁焊条
铸铁件
常温焊
接头组织与性能
micro-alloying cast iron electrode
iron casting
ambient temperature welding
microstructure and properties of joint
作者简介
翟秋亚，女，1963年出生，副教授。主要从事先进材料及其焊接方面的研究。发表论文40余篇。Email：qiuyazhai@xaut．edu．cn
