Low temperature fatigue properties of the joints of SMA490BW weathering resistant steel

Abstract

Microstructures of SMA490BW weathering steel welded joints are investigated. Tensile tests, impact tests and bending tests of joints were carried out to investigate the mechanical properties from the test temperature of 0°C to-40°C. And the fatigue properties of jonits at-40° C and 0°C are discussed in the article. Fracture surface of impact joints of different temperautre are observed. Well-formed welded joint has been obtained by MIG welding method. There are no cracks and other weld defects are found in the joints. In the temperature range of 0-40 °C, all the tensile specimens are broken at the base metal, and the tensile strength increases with the decreasing temperature. Impact toughness of weld decreases with the decreasing temperature. Fracture mode of base material transforms into quasi-cleavage fracture by the dimple mode at-40°C. Cleavage fracture surface is observed of the weld at the temperature of 0°C and-40°C. Cracks and other surface defects are not found in the bending test of the weld at the temperature of-40°C.