Failure Analysis of Intake Valve for A Locomotive Diesel Engine
Aiming at the failure accident of dropping blocks of a heavy-duty locomotive diesel engine intake valve during service,the cause of the intake valve failure was found out through the inspection and analysis of the macroscopic shape,fracture morphology,chemical composition,microstructure and mechanical properties of the failed intake valve,and the failure mechanism was also elaborated.The results show that the crack starts from the conical surface of the valve disc and propagates to fracture under the combined action of seating stress and thermal stress;the chemical composition,metallographic structure and forging streamline of the inlet valve do not meet the technical requirements,which reduces the thermal strength and bearing capacity of the inlet valve.The results of finite element analysis show that the peak stress is on the valve cone;due to the decline of the comprehensive mechanical properties of the intake valve,dropping blocks occur at the valve cone under the action of cyclic alternating stress.
diesel engineintake valvefailure analysisfinite element analysisheat treatment
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