摘要
用自动TIG焊在不同的焊接工艺条件下对S275NL低合金高强钢进行焊接。利用光学显微镜分析了焊接接头热影响区(粗晶区)金属的显微组织;测试了焊接接头热影响区的显微硬度。结果表明,如焊前不预热,焊后不保温缓冷,焊接接头热影响区(粗晶区)的组织比较粗大,硬度较高,不利于提高热影响区的冲击韧度;焊前进行150℃左右预热,焊后保温缓冷,且采用合适的焊接热输入(2.31 k J/cm),焊接接头热影响区(粗晶区)组织细小,分布均匀,且为等轴晶,硬度分布合理,有利于提高热影响区的冲击韧度;在不同焊接条件下,S275NL钢焊接热影响区均存在硬化现象。
The welded joints of S275NL HSLA steel are made by TIG automatic welding process in different welding process conditions. According to the specimens of welded joints involved, the analyses microstructure of the heat-affected zone （Coarse grained region） metal are made, and the micro-hardness survey of heat affected zone of welded joints is conducted. The results show that size of grains of HAZ is coarse, micro-hardness is higher than than other conditions if no preheating before welding and no slow cooling rate treatment measure after welding. So HAZ has worse impact toughness. On the countrary, crystal axis was smal land well distributed of HAZ （Coarse grained region） and if preheated before welding and slow cooling rate treated after welding and used little heat input （2.31 KJ/cm）. In this way, the HAZ has better impact toughness.S275NL steel welding HAZ has hardening phenomenonrin the different welding conditions.
出处
《铸造技术》
CAS
北大核心
2015年第2期499-501,共3页
Foundry Technology
