Fractured Valve Spring
A steel valve spring meeting Steel-Iron-Test 1570 fractured during the high-stress condition of the operation of its valve. Metallographic examination of a transverse section adjacent to the fracture and a longitudinal section through the crack showed the steel was free of major defects and was of high purity, although a number of minor surface defects such as rolling laps were found. The spring was heat treated and its surface strengthened by shot-peening, but the surface was also decarburized to a depth of approximately 0.03 mm which resulted in a lowering of the surface hardness. The fracture of this valve...
Friedrich Karl Naumann, Ferdinand Spies, Fractured Valve Spring, ASM Failure Analysis Case Histories: Mechanical and Machine Components, ASM International, 2019, https://doi.org/10.31399/asm.fach.mech.c9001158
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