摘要
系统研究了环境温度对手工自蔓延焊接燃烧过程和焊接质量的影响。结果表明,环境温度对焊接有较大影响,随温度升高,焊条的燃烧速度增快,燃烧剧烈;在低温环境中,燃烧型焊条仍能够维持燃烧反应,但燃烧速度和焊接热量降低,熔池能达到的最高温度明显降低,且冷却速率增快;低温环境焊接,易出现未焊透、未熔合、焊缝短、焊道成形差等现象,焊缝中出现气孔、夹杂和裂纹等缺陷的倾向明显增大。微观组织分析发现,不同环境温度下铜基焊缝的微观结构未发生变化,均为α-Cu固溶体基体上析出网状分布的富铁第二相。力学性能分析表明,低温环境中的焊接试件综合力学性能较差,平均抗拉强度158 MPa,高温环境焊接可达350 MPa以上。
The influence of the ambient temperature on the combustion performance and welding quality of manual self-propagating high-temperature combustion synthesis welding( manual SHS welding) was investigated systematically. Results showed that when the ambient temperature is higher,the combustion velocity of the welding rod increases and the rod is difficult to be operated. In low-temperature environment,thecombustion reaction can be still self-sustained,but the combustion velocity and the quantity of welding heat decrease,and the highest temperature of the weld pool becomes lower. The cooling rate of the pool is larger at lower ambient temperature,and the incomplete fusion,incomplete penetration and poor weld appearance often occur,and weld defects such as blowholes,inclusions and cracks in the weld metal appear more easily than that at high ambient temperature. Microstructure analysis showed that the microstructures of the weld metal at both low and high ambient temperature are the same. The matrix is α-Cu solid solution,with reticular Fe-rich second phase. Mechanical properties test indicated that the mechanical properties of welded joint at low ambient temperature is lower than that at high ambient temperature. The tensile strength is higher than 350 MPa at high ambient temperature,and 158 MPa at low ambient temperature,respectively.
出处
《焊接》
北大核心
2016年第11期53-56,74-75,共4页
Welding & Joining
关键词
手工自蔓延焊接
环境温度
燃烧过程
焊接质量
manual SHS welding
ambient temperature
combustion process
welding quality
