Flux Cored Wire for Steel Sheet with Fatigue Strength Improvement

Abstract

A flux cored wire for to steel sheet welding in automobile industries has been developed. The present wire is designed to reduce the slag formation to the level of conventional solid wire by controlling oxides in the flux. The present wire also contains comparatively high C, Ni and Cr so as to improve fatigue strength of a lap joint. The experimental results of plane bending fatigue tests reveal that the fatigue strength at 2 million cyclic loading is about 50% higher than that of ordinary solid wire. The charpy tests using the 1/4-size V notch specimens show that the absorbed energy of the present wire's weld metal at —40°C is almost equivalent to that of the conventional solid wire. Hence, it is concluded that the flux cored wire developed in the present work can be applied to steel sheet welding in automobile industries with high fatigue strength and high charpy impact properties.