A study of solidification crack susceptibility using the solidification cycle hot-tension test

Abstract

Solidification cycle hot-tension testing was performed using a Gleeble-1500 simulator to examine its suitability for the simulation of austenitic weld metals, and to evaluate further their solidification crack susceptibility. The effects of niobium on the hot ductility and the sensitivity to solidification cracking of the austenitic stainless steel weld metals were accurately evaluated by this method, combined with a systematic study by scanning electron microscopy, electron-probe micro-analysis, transmission electron microscopy and phase analysis. The solidification crack susceptibility increases with increasing niobium content, up to critical value of approximately 1.1%, and then decreases. The harmful effect of niobium is attributed to the formation of a low-melting eutectic (FeCrNi) 2Nb-γ along the grain boundaries. The critical value of niobium content is related to the synergistic effects of the “healing” function of sufficient low-melting eutectic, and the beneficial effect of a small amount of ferrite. The corresponding Transvarestraint test results for the same materials demonstrate the reliability of evaluation by the solidification cycle hot-tension test. The study indicates that it is an effective method for evaluating the solidification crack susceptibility.