Influence of alloying elements in low temperature transformation Weldment on Ms. temperature, microstructure and mechanical properties

Abstract In this study, we investigated the influence of alloying elements in low temperature transformation weldment on Ms. temperature, microstructure and mechanical properties in terms of metallurgy. The Ms. temperatures were controlled by chemical composition of Cr, Ni and Cr equivalent/Ni equivalent (Creq/Nieq) ratio. Dilataion analysis and Thermo-calc calculation during cooling of weldment were proceeded to determine relationship between the chemical composition and the microstructure. The austenite volume fraction increased as decreasing Ms. temperature at the same Creq/Nieq ratio. The volume fraction of proeutectic δ-ferrite increased with increasing Creq/Nieq ratio at the same Ms. temperature. Due to increasing the volume fraction of proeutectic δ-ferrite which was located along grain boundary the impact toughness was decreased.