Inappropriate fastening system, improper torque Improper tools Inappropriate modification Inadequate surface preparatio Inspection Techniques Arc burn due to magnetic particle inspection Intergranular attack or embrittlement due to macroetch Fatigue or quench crack from steel stamp mark xample 4: Forming Process Anomalies in Diesel Fuel Injection Control Sleeve(Ref 28 ). A user complained of a diesel engine that failed to start in cold weather. Troubleshooting isolated the problem to the diesel fuel control assembly, which was changed out, fixing the problem. Teardown of the fuel control assembly by the manufacturer revealed that a small subcomponent known as the cold start advance solenoid sleeve(Fig. 21) was leaking through the wall. The sleeve operates under relatively high pressure cycles in service. This component is a tubular product with a"bulb section at one end and threads on the other The manufacturing method used to create the bulb shape was hydroforming, using a 300 series stainless steel tube in the full-hard condition Fig. 21 Cold start advance solenoid sleeve. 0.85x The leak was attributed to a crack in the sleeve(Fig. 22), in the radius between the bulb area and the cylindrical portion of the sleeve. Scanning electron microscope examination of the broken-open crack revealed fatigue cracks initiated at multiple sites near the outside diameter(oD)of the sleeve(Fig. 23). The crack origins were determined to be extending from shallow(0.013 mm, or 0.0005 in. ) zones exhibiting ductile shear(see area between arrows in Fig. 23). Viewing the OD surface of the sleeve adjacent to the fracture plane revealed an extensive network of microcracks on the od in the radius between the bulb and cylindrical portions(Fig. 24 ). A cross section through one of the fatigue crack origins revealed slip bands emanating from the microcracks(Fig. 25) Thefileisdownloadedfromwww.bzfxw.com· Improper fit-up · Inappropriate fastening system, improper torque · Improper tools · Inappropriate modification · Inadequate surface preparation Inspection Techniques · Arc burn due to magnetic particle inspection · Intergranular attack or embrittlement due to macroetch · Fatigue or quench crack from steel stamp mark Example 4: Forming Process Anomalies in Diesel Fuel Injection Control Sleeve (Ref 28). A user complained of a diesel engine that failed to start in cold weather. Troubleshooting isolated the problem to the diesel fuel control assembly, which was changed out, fixing the problem. Teardown of the fuel control assembly by the manufacturer revealed that a small subcomponent known as the cold start advance solenoid sleeve (Fig. 21) was leaking through the wall. The sleeve operates under relatively high pressure cycles in service. This component is a tubular product with a “bulb” section at one end and threads on the other. The manufacturing method used to create the bulb shape was hydroforming, using a 300 series stainless steel tube in the full-hard condition. Fig. 21 Cold start advance solenoid sleeve. 0.85× The leak was attributed to a crack in the sleeve (Fig. 22), in the radius between the bulb area and the cylindrical portion of the sleeve. Scanning electron microscope examination of the broken-open crack revealed fatigue cracks initiated at multiple sites near the outside diameter (OD) of the sleeve (Fig. 23). The crack origins were determined to be extending from shallow (0.013 mm, or 0.0005 in.) zones exhibiting ductile shear (see area between arrows in Fig. 23). Viewing the OD surface of the sleeve adjacent to the fracture plane revealed an extensive network of microcracks on the OD in the radius between the bulb and cylindrical portions (Fig. 24). A cross section through one of the fatigue crack origins revealed slip bands emanating from the microcracks (Fig. 25). The file is downloaded from www.bzfxw.com