Prediction of Cooling Time for Ferrite-Austenite Transformation in Duplex Stainless Steel

Abstract

Study has been carried out aimed at predicting the cooling time from 1200 to 800°C (t12/8) of arc welds in stainless steel using an existing heat flow model and direct measurement of the weld thermal cycle. The properties of welds in austenitic-ferritic duplex stainless steel depended on the delta (δ) ferrite content of the weld metal (WM) and the heat affected zone (HAZ). The t12/8 was the major cooling parameter relating to the δ-ferrite content. It was shown that the travel speed and the distribution of the heat source had negligible effect on the value of t12/8 in a practical welding situation. The proposed equation predicted t12/8 with an error of approximately 15% relative to experimental measurement. © 1995, The Iron and Steel Institute of Japan. All rights reserved.