摘要
高压环境会造成焊接电弧收缩,焊接过程较不稳定。鉴于脉冲熔化极气体保护焊（Pulsed gas metal arc welding,GMAW-P）具有热输入量可控、电弧挺度较好等特点,将其应用于高压环境下是一个有益尝试。开展压力在0.1～1.0 MPa范围内不同极性下的干法GMAW-P试验,分析随着环境压力升高电流电压波形图的变化趋势,由此确定焊接极性不同时焊接过程稳定性随环境压力升高的变化规律;在此基础上,对比分析不同极性下GMAW-P焊接飞溅及焊缝成形随压力升高的变化规律。随着环境压力增加,在直流反接情况下,电流电压波形周期性逐渐减弱,焊接过程趋于不稳定,飞溅逐渐增多,焊缝成形变差;而采用直流正接方式时,高压下电流电压波形的周期性虽然不及常压下稳定,但相较于同一压力下的直流反接方式,周期规律性有所增强,焊接过程相对稳定,且焊接时产生的飞溅比采用直流反接方式时的飞溅少且颗粒小。另外,随环境压力增加,两种极性GMAW-P焊缝宽度均有变窄的趋势,余高也随之增加。对高压环境下不同焊接极性GMAW-P的电弧形态及相应电弧力进行深入探讨,明确了上述现象出现的原因,为高压环境下焊接工艺的改进提供有效的理论依据。
The hyperbaric environment can cause contractive welding arc and unstable welding process. Since pulsed gas metal arc welding （GMAW-P） has the characteristics of controllable heat input and good arc stiffness, it is a useful attempt to apply GMAW-P under the hyperbaric environment. Experiments of underwater dry GMAW-P with different polarities are carried out at ambient pressures of 0.1-1.0 MPa, and the variation tendency of the current and voltage waveforms along with the increase of the ambient pressure is analyzed, thus the change regulations of the welding process stability for GMAW-P with different polarities are determined along with the increasing ambient pressure. Based on this, the variation regulations of the welding spatters and the weld appearances of GMAW-P with different polarities are analyzed comparatively with the increasing ambient pressure. Along with the increase of the ambient pressure, the periodicities of the current and voltage waveforms are gradually weakened, and the welding process tends to be unstable, the spatters are gradually increased, and the weld appearance becomes worse for GMAW-P with electrode positive polarity（DCEP）. While GMAW-P with electrode negative polarity（DCEN） is applied, the periodicities of the current and voltage waveforms under high pressure are less stable than that at one atmosphere, but compared with GMAW-P with DCEP at the same pressure, the periodic regularity is enhanced, the welding process is relatively stable, and spatters produced during the welding process are less and smaller. In addition, the weld widths of GMAW-P with DCEP and DCEN are reduced and the reinforcements are increased with pressure. The arc shape and corresponding arc force of GMAW-P with different polarities under the hyperbaric environment are discussed, and the reasons for the above phenomenon are confirmed, which provide effective theoretical basis for the improvement of welding process under the hyperbaric environment.
作者
黄军芬
薛龙
黄继强
吴金明
刘剑
HUANG Junfen XUE Long HUANG Jiqiang WU Jinming LIU Jian(Opto-Mechatronie Equipment Technology Beijing Area Major Laboratory, Beijing Institute of Petrochemical Technology, Beijing 102617)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2016年第18期64-69,共6页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(51275051)
关键词
高压焊接
极性
飞溅
焊缝成形
hyperbaric welding
polarity
spatter
weld appearance
