Crack analysis of needle body of diesel engine high pressure common rail injector
To solve the problem of cracking at the scapular corner of the injector needle valve body,methods such as scanning electron microscope,energy dispersive spectrometer,microhardness testing,and CT are used to analyze the cause and failure mechanism of the fault,and solutions are proposed.The results show that the surface of the failure site contained corrosive elements such as S and Cl,and there are multiple irregular corrosion pits on the crack surface.The Vickers hardness at the crack site decreased by 28%than that at the scapular corner of the needle valve body,and the minimum wall thickness decreased by 47%compared to the normal part,and the main cause of needle valve body failure is corrosive cracks.Use fuel that meets national standards and add coatings on the surface of the needle valve body can solve the problem of needle valve body corrosion failure.