Prevention of welded joints porosity during welding of austenitic steels by high-effective electrodes

Factors were determined governing the probability of formation of pores in welding of high-alloy austenitic steels by high-efficiency electrodes with iron powder in the coat. Investigated was the effect of a coat composed of a widely used system TiO2-MgCO3-CaF2 upon the content of gases and non-metallic inclusions in a chromium-nickel deposited metal of the 18-10 type. Studied was also the effect of the composition of coats upon the dimensions and the shape of droplets formed by a melting electrode and characterizing the variation of the surface properties of the liquid metal. The investigations were conducted using the experimental design and the mathematical statistics methods. It was shown that pores in welds could be effectively avoided by providing the three following factors: good wetting of the solidifying metal by the liquid metal; low surface tension of the welding pool metal; small amount of coarse non-metallic inclusions in weld metal