STUDY ON APPLICATION OF ELECTROGAS ARC WELDING TO SM570 STEEL IN BRIDGE FABLICATION

Abstract

The application of high heat input welding such as electrogas arc welding (EGW) has been demanded for the efficiency in steel bridge fabrication. The influence of steel chemical compositions and welding heat input on heat affected zone (HAZ) toughness was investigated in EGW joints of SM570 steel. From the view point of the HAZ toughness at -5°C, low C-Ti added SM570 steel is available to the EGW having heat put up to about 13kJ/mm. The formation of HAZ microstructure is mainly influenced by the chemical compositions and the welding thermal cycle represented by cooling time from 800°C to 500°C, and consequently, the microstructure dominates the toughness.