Effects of Vanadium on the Properties of 2 1/4Cr-1Mo Electroslag Weld Metals

Abstract

It had been shown that hot tensile strength and thermal embrittlement were improved by a small addition of vanadium about electroslag weld metals of heavy section 2 1/4Cr-1Mo steels which were usually used for high temperature and pressure vessels such as direct desulfurizing processes.
Effects of vanadium on the properties of the weld metals were more precisely discussed in this study. The main conclusions are as follows:
(1) Reheat cracking susceptibilities were not changed in the electroslag weld metals even if the vanadium was addde up to 0.12%.
(2) Tneisle strength at room temperature and at 435°C were linearly increased with vanadium content up to 0.07% and up to 0.03%, respectively. More addition of vanadium up to 0.12%, however, did not changed both tensile strength and kept them constant. Factured elongation was gradually decreased with vanadium addition at first, and then became constant or a little increasing.
(3) Thermal embrittlement of the weld metal was drastically improved with vanadium addition and the weld metal with 0.12% V was judged practically immune from thermal embrittlement.
(4) Favorable effect of vanadium on thermal embrittlement was mainly attributed to prevention of precipitation of P and Mn on grain boundaries.