粗丝CO_2气体保护焊熔滴过渡与潜弧机理的研究

The Metal Transfer and Burued Arc Mechanizm in Thick Wire Carbon Dioxide Arc Welding

本文详细分析了粗丝CO_2气体保护潜弧焊熔滴过渡的特点和潜弧机理。潜弧状态可以分为三种类型:半潜弧(熔滴主要以较大的颗粒形式过渡)、临界潜弧(熔滴主要以较小颗粒的射滴形式过渡)和深潜弧(熔滴以细小射滴与射流混和形式过渡)。大电流、低电压、粗焊丝、反极性和氧化性气氛是形成潜弧过程的必要条件,其中电流是最重要的条件。潜弧后弧柱气氛改变,焊丝端部的弧根由集中形态扩展为覆盖整个端部形态,使得熔滴尺寸变得细小,熔滴过渡形式发生变化。采用临界潜弧区域的焊接规范参数施焊,飞溅小,工艺过程稳定,焊缝成形优良。

The features of the metal transer in different buried arc forms and the buried arc mechanism have aeen carefully investigated by observing the dinamic process taken by nac-16HD high speed camera in thick wire carbon-dioxide are welding. The types of the buried arc can be divided into three groups: half buried arc (the droplets of about the same size as wire diameter transfer to the pool) . critical buried arc (the droplets transfer to the pool in projected transfer form) and deep buried arc (the droplets transfer to the pool in projected and streeming transfer forms). The high current, low voltage, reverse polarity, oxidative shielding gas, thick wire are the essential conditions of formation of the buried are, the high current being the most important factor. After the arc has been buried, the arc column gas atmosphere is changed and the concentrated arc on the wire tip becomes a covered one, which makes the droplets size smaller and the droplet transfer form change. The appearance of weld is better and the welding process with low spatter is more stable when the arc is a critical one.