Abstract
To improve the toughness of electro-gas weld metal, several kinds of electrode wires with various contents of aluminum and molybdenum were prepared. Weld metals of 20 mm and 32 mm low carbon steel plates using these electrode wires were examined for mechanical properties, microstructure and non metallic inclusions.
1) A microstucture of electro-gas as-welded metal containing aluminum and molybdenum is finer grain than that of as-welded metal containing only aluminum. And the impact value of the former is higher than that of the latter.
2) A small aluminum content improved the fatigue strength of weld metal but a higher content did not.
3) A chain or film of sulphide inclusions was observed by an electron-microscope in the weld metals of a relatively higher aluminum content.
