The Experimental Research Of45~#Steel Component's Faigue Damage Reparring With Electric

In this article we research the fatigue life and microstructure change of metal fatiguedamage specimens after pulse current treatment through experiments,and The testmaterial is45#steel.First,take one group of specimens for tested to get the fatigue life of determinationof Nf, at the same time take the other two groups of specimens for fatigue damagepreparation on the EHF-EM electro-hydraulic servo fatigue test testing machine,respectively to the expected90%Nfand80%of Nfcycles, and take this two groups ofspecimens for repairing experiment with high pressure pulse discharge, and then take therepaired specimens for the fatigue testing again under the same conditions of fatiguecyclic loading, until the fatigue fracture failure happens, and the purpose is to confirmthe repaired specimens' remainder fatigue life. After comparison, the specimens fatiguelife of repaired increased obviously.Second, observe the specimens of fatigue fracture characteristics of morphology byscanning electron microscope, observed that the fracture morphology in different stagesof the fatigue damage characteristic. And, using the X-ray diffraction experimentmeasured the specimen in fatigue before and after damage micro strain, and the microstrain change before and after processing, but also to the changes of the residual stresswere studied. The results of X-ray diffraction experiment show that the materialmicrostructure have obvious change, the determination results of micro Strain, The microstrain of fatigue fracture specimens is lower than the specimens with damage beforeprocessing, higher than the the repaired, far higher than original specimens'. Thedetermination results of residual stress show that the residual stress of specimens of90%of fatigue life is higher than the80%after the repairing with pulse discharge, alsosignificantly higher than the original specimens of45steel.In this paper that the test of pulse current treatment on the metal fatigue damagerepair function potential cause, basically have two aspects, one is the heating effect ofthe pulse current, make damaged area recrystallization and its grain growth, the internal damage of metal material healing; The other effect is the pulse current electric power, forthe electric power function, the crystal particle of the damage spread and make thedamage healing, also may be the two kinds of utility joint action, this will be studiedcontinue.