Influence of High-Temperature Ageing on the Microstructure of Stainless Steel/Low Alloy Steel Clad Plate Welded Joints

摘要

This paper studies the microstructure of welded joints of Q345R/304 stainless steel clad plates after high temperature ageing. E309Nb welding rod, ER310 welding wire, and ER309L welding wire were used as cladding filling materials, and ER50-6 welding wire was used as base-layer filling material for welding. The metallographic microstructure of welding joints were studied after ageing treatment at 600°C for 100 hours. Test results showed that the microstructures of cladding weld zone were austenite and ferrite, and the ferrite in cladding weld zone of ER309L welded joints is less than the one in cladding weld zone of E309Nb and ER310 welded joints. The microstructure in the fusion zone is in-continuous, and the fine ferrite is distributed on the austenite matrix. After high temperature ageing, the width of fusion zone in ER309L welded joints is obviously less than that of the other two welded joints. The toughness of ER309L welded joints is better than that of E309Nb and ER310 welded joints.