High Quality Common Rail Diesel /Fuel Injector NozzleDLLA148P062

Analysis of why the injector nozzle stuck in the injectors. (part 3)

2.3.2 The surface hardness of the nozzle is 720HV1～780HV1, the thickness of the carburized layer is 0.6mm～0.8mm, and the retained austenite shall not exceed 15%. The surface hardness of the initial steel stamp number HHM nozzle is HV0.2588, which is much lower than the design requirements, the thickness of the carburized layer is 0.6mm, the level of martensite is 2, and the retained austenite is level 1; the surface hardness of the initial stamp number HD nozzle is also low at HV1615 According to the design requirements of HV1720, the thickness of the carburized layer is 0.86mm, the level of martensite is level 4, and the level of retained austenite is level 3. The inner hole hardness of the two nozzles did not meet the design requirements. The material of the needle valve is W6Mo5Cr4V2, the national standard requires the C content to be 0.8% to 0.9%, and the V content to be 1.75% to 2.20%. The measured initial stamp number HD needle valve C content is 0.7%, V content is 1.09%, and the C and V content are lower than the national standard requirements;

2.3.3 The C content of the initial stamp number HHM needle valve is 0.72%, the V content is 1.19%, and the C and V content are lower than the national standard requirements. The other alloy elements of the two-needle valve are within the range required by the national standard. The material of the nozzle is 18Cr2Ni4WA, the C content of the initial stamp number HD nozzle is 0.20%, and the national standard requires 0.13% to 0.19%, and the content of the rest of the alloy elements of the nozzle is within the range required by the national standard. All alloying elements of the initial steel stamp number HHM nozzle are within the range required by the national standard.