超高频脉冲电弧焊接熔池金属流动行为

熔池金属流动一方面受电弧行为影响,另一方面与凝固组织形核、结晶过程联系紧密,是电弧焊接基础研究的关键,针对电弧力作用研究了超高频脉冲电弧焊接(UHFPAW,Ultra High Frequency Pulsed Arc Welding)熔池金属流动特点,采用理论研究与试验分析相结合的方式对熔池流动方式、强度、温度分布等要素进行了分析,并完成了液态金属表面运动特征监测.结果表明,超高频脉冲电弧对熔池液态金属的热、力作用显著,表面流体流速大于30 cm/s,UHFP-AW电弧力造成熔池表面沉降变形,引起双环流,熔池温度扩散范围相应减小,有效降低了电弧热量对母材金属的影响,尤其在钛合金焊接中对控制焊缝晶粒尺寸具有重要意义.

Metal molten behavior with ultra high frequency pulsed arc welding

Molten liquid metal is the key factor of the fundamental research during welding process, as it is the transfer element between arc behavior and solidification. Researches of the characteristics of molten pool were carried out by ultra high frequency pulsed arc welding (UHFP-AW), especially with the focus on the effect of arc force. The methods combining experiments and theoretical study were produced for the analyses of important factors, such as fluid status, velocity and temperature distribution of molten pool. And the fluid in molten surface was monitored as the supplement for further study. The results indicate the significant effect of the arc plasma on heat and force of molten pool with UHFP-AW. The monitor data demonstrate that the velocity of surface fluid is more than 30cm/s, and the double-circulation exists with surface depression caused by larger velocity during UHFP-AW. As a result, the temperature diffusion of molten pool would reduce, which can limit the impact of arc heat on base metal effectively. It is the key for controlling the grain size of titanium alloys with arc welding process.