Influence of Welding Regimes on Structure and Properties of Steel 12KH18N10T Weld Metal in Different Spatial Positions

Welding of 12Kh18N10T stainless steel in vertical and overhead positions with welding transformers and welding rectifiers requires a reduction in the welding current. A reduction in welding current leads to a reduction in transfer of alloying elements into the welding pool and, as a consequence to a reduction in weld mechanical properties. In this article a welding inverter is used for vertical and overhead welding in standard operating regimes, as for the lower position. Metallographic analysis and chemical composition analyses are conducted for the specimens obtained; the ferritic phase content and transfer coefficients for elements into the weld are determined. It is found that the content of alloying elements for all three samples prepared by lower, vertical, and overhead welding (samples V1, O1 and D1) using a welding inverter either hardly differs (Cr, Mn, C), or changes very slightly. The reduction is no more than 15–18% (when comparing D1 and O1 specimens). Also, the ferritic phase content does not exceed 10%, which points to resistance of the resultant weld and HAZ to cracking. After eight hours of testing in a boiling aqueous copper sulfate and sulfuric acid solution intergranular cracking and grain-boundary failure are not revealed by optical metallography in the HAZ. The transfer coefficient of alloying elements for all the specimens obtained is compared with those prepared by standard technology with a reduction in welding rectifier current. For Mn, Si, and Cr, the transfer coefficients hardly differ for all specimens D1, V1, and O1. For Nb and Ni the transfer coefficient for specimens D1, V1, and O1 is significantly higher than for those prepared under standard conditions.