Study On The Effect Of Thermal Correction On The Properties Of Bogie Frame With Q345E Low-alloy Steel And Joints

Welding distortion is a common phenomenon in welding structure manufacturing process, although the adopted measures, but the welding deformation is always inevitable, must pass through correction to satisfy the use requirement. Usually correct welding structure deformation method has two kinds: namely mechanical correction method and flame rectification. Flame rectification is also called thermal correction which is the most commonly used method in the welding structure or method of making correct welding deformation. In the past few people study the process parameters to the correct material and the study of the influence of the welding joint performance, so the objective of the study for the bogie welded frame production has very important practical significance.The main contents of this paper are as below: The microstructure and performances of Q345 E low-alloy steels with different thermal correction studied through the conventional mechanical tests such as tensile, bending, impact, hardness and microstructure analysis. Correction of Q345 E low-alloy steels of different temperature microstructure and properties of welded joint are studied; By pulsating tensile fatigue test and three point bending fatigue test, respectively, to remove residual high Q345 E low alloy steel butt joint butt joints and T-corner joints of fatigue performance were studied, and the correction of 700℃, 800℃ and 1000℃ corrected correction of welding joint and not correct values in the fatigue strength of welded joints are analyzed in comparison.Correct temperature of Q345 E low alloy steel welding joint will have minimal impact on tensile, bending and impact performance. Q345 E low alloy steel welding joint of different correction temperature microstructure is blocky ferrite and a small amount of pearlite; The center of the weld microstructure are ferrite + pearlite, weld layer microstructure are similar; The microstructure of fusion zone are a small amount of pearlite and first eutectoid ferrite; For HAZ microstructure are ferrite and pearlite. Q345 E low alloy steel in different temperature correction microhardness of welded joint are basically the same, the microhardness of weld are same, the microhardness variation of HAZ is not obvious. As correct temperature rise, remove residual high Q345 E low alloy steel butt joint the pulsating tensile fatigue strength has a downward trend, 700℃ correction reduced the 0 MPa, 800℃ correction reduced the 10 MPa, 1000℃ correction reduced the 30 MPa; T-corner joints fatigue strength is on the rise, 700℃ correction increased 45 MPa, 800℃ correction increased 45 MPa, 1000℃ corrective increased 47.5 MPa. Comprehensive consideration, reasonable for Q345 E low alloy steel welding joint correction flame temperature is 600℃ ~ 800℃, 700℃ correction comprehensive performance is the best.