Effect of Heat Affected Zone of Thermal Cutting on Microstructure and Properties of Welded Joints of Q345E

Through the anti-cracking test,tensile tests,impact test,bending test,microhardness test and metallographic analysis of hot cutting heat affected zone,the effects of the HAZ of thermal cutting on microstructure and mechanical properties of Q345E welded joint were studied.The test results show that the flame cutting heat affected zone is wider than machining and lower in hardness.Two kinds of welded joint have good crack resistance,impact toughness,stretching and bending performance.The weld lane is eutectoid ferrite distributing in dendrites.Heat affected zone is massive ferrite along the grain boundaries,the raw material is ferrite+pearlite.So before welding,the process flame cutting groove is feasible.