THE INFLUENCE OF THE AIR PLASMA BEVELLING PROCESS ON THE QUALITY OF MAG WELDED STEEL JOINTS

In the article an influence of mild and low alloy construction steels preparation in the mean of air plasma cutting on quality of welded joints has been described. The way of this preparation, its accuracy and method affect the quality of the joints. The impact of air plasma cutting on chemical composition and microstructure of processing materials has been presented in this article. Surfacing and MAG (metal active gas) welding of steel sheets prepared by air plasma cutting have been done including mechanical HAZ and oxides layer removal and without oxides removal. X-ray, macro and microscopic examinations were performed. In the case of welded joints, additional mechanical tests and hardness measurements were performed. It has been shown that the high content of nitrogen in the outer layer resulting from air plasma cutting may lead to porosity during GMA welding (Gas Metal Arc-referred to by its subtypes metal inert gas (MIG) and metal active gas (MAG)) The porosity can be found in the root of weld as well as in the fusion line of filling beads.