Abstract: Based on the characteristics of existing electrode performance, in view of the poor weld ability of typical low alloy steel electrode (E5515) when it is used to weld CE>0.4% medium high carbon-steel, micro-amount rare earth oxide is transferred through the electrode coating in the development of formula for the new type low alloy steel electrode. Through impact toughness, tension, hardness and metallographic tests, etc., the influence of the cerium oxide on mechanical properties and microstructure of the deposited metal of a low alloy steel electrode is studied, microstructure is observed by using scanning electron microscope, energy spectrum is analyzed by using X-ray energy dispersion spectroscopy. The results show that the addition of rare earth can effectively refine the microstructure and improve the impact toughness of deposited metal; the rare earth can decrease the hydrogen of deposited metal, so that it dramatically decreases brittle transition temperature of steel. When the amount of added cerium oxide ceria is optimal, the tensile strength of deposited metal is improved by 43.27%, the yield strength by 52.11%, the impact ductility by 26.49%, yet the hardness does not decrease.

Key words: Cerium oxide, Deposited metal, Low alloy steel electrode, Mechanical properties, Microstructure