Microstructure and Properties of Q345E Lamellar Tearing Resistant Steel SAW Welding Joints
The Q345E lamellar tearing resistant steel with 140mm thickness was welded by submerged arc welding (SAW). The microstructure and properties of the welded joints were investigated. Affected by the long-term welding thermal cycle, microstructure at different thickness has great differences. The hardness in the weld center is higher about 55 HV than the base metal. Due to the grains refinement of the microstructure at 1/2 thickness was more obvious, the microhardness of this zone has a more obvious dispersion degree. The average grain size of ferrite at the 1/4 thickness is about 10 μm, which resulted in two samples at this thickness obtain a higher tensile strength (496.568 MPa and 496.36 MPa). Moreover, part of the pearlite lamellar in the HAZ at 1/4 thickness had been fragmented and spheroidized.
X. Q. Si et al., "Microstructure and Properties of Q345E Lamellar Tearing Resistant Steel SAW Welding Joints", Applied Mechanics and Materials, Vol. 628, pp. 48-52, 2014