Cracking: Cracking of a hydraulic wrench presents a shallow turtle-like crack on the surface of the forging. Such defects are most prone to the surface that is stressed in forging (eg, underfilled bulges or bent portions). 

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Causing internal causes may be multifaceted: For example, raw materials such as cu, sn and other fusible elements too much. When heated for a long time at high temperature, there is copper precipitation on the steel surface, coarse grain surface, decarburization, or surface after repeated heating. There are too high fuel sulfur content, sulfur infiltration of steel surface.

Flaw Crack: Crack is the edge of die forging and trimming at the parting plane generated cracks. Hydraulic wrench flash cracks may be due to reasons: in the swaging operation as a result of heavy metal flow through wear phenomenon. Magnesium die forging pieces trimming temperature is too low, copper alloy die forging trimming temperature is too high and so on.

Parting surface crack: Parting surface crack refers to the cracks along the forging parting surface. Non-metallic inclusions and more raw materials, hydraulic wrench die forging flow to the parting surface flow and concentrate or shrink tube residual die forging squeeze flash often form parting surface cracks.