关键词: C276合金, 显微组织, 抗拉强度, 腐蚀电流密度

Abstract: This paper adopts OM and SEM methods to carry out process research on the microstructure and properties of laser weld joints of C276 alloy. The research indicates that the weld of this alloy consists of austenite, and its morphology is closely related to heat input. The heat affected zone (HAZ) is composed of coarsened equiaxed austenite grains and precipitates along grain boundary. Comparing the microstructure of weld joints with four different parameters, it is found that the weld with heat input of 30J/mm is composed of fine equiaxed crystal and cell crystal austenite. With increasing heat input, the morphology of austenite is gradually transformed into columnar crystal. The mechanical properties tests show that weld is the weak area in joint. The strength, hardness and elongation of welding decrease with the increase of heat input. The electrochemical test shows that in simulated acid environment, the corrosion resistance of the weld is weaker than that of the base metal; and the larger the heat input, the worse the corrosion resistance of the weld. This indicates that the joint with low heat input of 30J/mm has good combination of plasticity, strength and hardness, and good corrosion resistance.

Key words: Hastelloy c276, microstructure, tensile strength, corrosion current density