LU Erjing, GUI Hongli, ZHANG Yanhui, et al. Study on microstructure and fatigue performance of Q310/Q345 resistance spot welding joint[J]. Eletric Welding Machine2018, 48(7): 62-66.DOI:
pulsating tensile fatigue test and the analysis of fatigue fracture morphology
this paper studied the microstructure and fatigue performance of resistance spot welding joint of 1.5 mm Q310 and 3 mm Q345. The results show that
the microstructure of Q310 and Q345 are similar
the base organization is pro-eutectoid ferrite and pearlite
the microstructure of HAZ is a few ferrite and pearlite. The microstructure of nugget area is lath martensite and bainite. From the nugget area to the base material
the hardness value distribution is in a step downward trend
the hardness value of nugget is the highest of the whole joint. The fatigue fracture is located in the nugget area. And the type of fatigue fracture is mixed with micropore and cleavage
the main cause of fatigue fracture is stress concentration.