air jordans Motorcycle engine exhaust valve failur

Motorcycle Engine Exhaust Valve Failure Analysis

Phase, resulting in decreased oxidation resistance, the exhaust valve in the work process due to the role of high temperature and oxidation atmosphere, oxidation corrosion fatigue, eventually leading to fracture. Keywords: exhaust valve; oxidation; nitride; corrosion fatigue; failure analysis CLC: TG156.8 +2 Document code: A Article ID :1001-3814 (2007) 14-0047-03AnalysisonFractureCauseofExhaustValveofMotorbikeEngineCHENMing, CAOBiao, TANYing , ZHOUQi, MOMing-zhen (GuangdongEntry-exitInspection & QuarantineTechnologyCenter, Guangzhou510623.China) Abstract: Analysesonmacro,[link widoczny dla zalogowanych], metallography,[link widoczny dla zalogowanych], chemistryandfractureappearancewerecarriedonbrokenexhaustvalveinmotorbikeengine. Theresultsshowthatdense ?-phasewimcorrosion-resistanceisn 'tformedonthesurfaceofexhaustvalveduringnitriding, whichreducestheoxidation-resistanceofit. Oxidizing-corrosionfatiguehappenedbecauseofhightemperatureandoxidizingatmosphereduringworking, andcausedtheruptureoftheexhaustvalve. Keywords ~ exhaustvalve; oxidation; nitriding; corrosionfatigue: failureanalysis a motorcycle production plant in Guangdong a motorcycle in motion a 12600km exhaust valve when the engine was broken. Exhaust valve material is made in Japan SUH35. Production process: forging a heat treatment of a machining of a nitride of a finishing machining of a finished product inspection. Should require manufacturers to analyze the fracture causes. Exhaust valve end plate fracture in the neck. Figure l. Disc cone surface and section has been seriously deformed by the collision. Department of fracture surface of the side bar showed obvious signs of rust as shown in Figure 2. Figure 1,[link widoczny dla zalogowanych], the exhaust valve fracture appearance of Fig. Ministry to take the exhaust valve stem 1Exteriorofbrokenexhaustvalve fracture scanning electron microscopy. The results shown in Figure 3. Can be seen in the fracture edge of many small steps. Conchoidal pattern can be seen clearly in cross section,[link widoczny dla zalogowanych], short interruptions located within the cross section and smaller. Instant-off zone microstructure shown in Figure 4. Show that the fracture is much higher due issued on the date of the source: 20o7.01.16 Author: Chen (1965 *), male, Zhanjiang, Senior Engineer, Master; Tel :020-38290519; E-mail. . chenm @ gdciq. gov. ca Figure 2 the exhaust valve side of the fracture surface rust Fig. 2Rustnearthefracture force low cycle fatigue. Crack originated in the surface. After more than meets the fatigue crack growth step, the crack continues to expand to the final fracture occurred fault. Figure 5 is the root source of fatigue, can be seen in the shank surface oxide layer,[link widoczny dla zalogowanych], and also found that many micro-cracks parallel with the cross section (arrow refers to the site.) Section shows a white spot area (Fig. 6), combined with metallographic and EDS can be determined for the oxide film off spot: the area are found in the fatigue growth typical \Further oxidation of presumed fault is corrosion fatigue fracture. Sampling of the exhaust valve to test the chemical composition. The results meet the requirements. According to the old / 1r6720-1993 standard and the thickness of the substrate layer routine metallographic examination, the results were normal situation. T-phase nitrided layer obtained for the gas main stem fracture system for horizontal and vertical positions, respectively (Figure 8a, b) metallurgical samples and found that the fracture surface and the surface of shank exist in a layer of \l4 of

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