EFFECTS OF THE PERFORMANCE OF SHIP STEEL FOR HIGH HEAT INPUT WELDING BY MICRO-ALLOY ELEMENT

摘要

Orthogonal experimental design is used to study the effects of alloying elements Ti, Nb and Zr on strength, toughness of base metal and quantity of M-A constituent in HAZ of ship plate. The results show that Nb has the greatest influence on strength and toughness of base metal. Strength is enhanced intensively with the increase of Nb quantity. Ti has the greatest impact on toughness in HAZ. Toughness in HAZ is the highest when Ti/N is appropriate. Nb is adverse to toughness in HAZ. Superfluous Ti and Nb increase quantity of M-A constituent in HAZ. Moderate Ti (0.012～0.016%) and Nb 0.015～0.025% should be used in ship steel design for high heat input.