Notched-bar microstructure-crack initiation method used for chipless fine blanking

Abstract

The invention provides a notched-bar microstructure-crack initiation method used for a chipless fine blanking. The method comprises putting a whole metal bar prefabricated with an annular "V"-shaped notch into a resistance heating furnace, setting a heating rate of the resistance heating furnace, energizing the resistance heating furnace, heating the metal bar to 300-1000 DEG C, stopping heating, insulating; moving the metal bar from the resistance heating furnace to a bar chilling device, opening power of the bar chilling device so that the metal bar rotates in the bar chilling device, adjusting a flow rate of cooling water, opening power of the cooling water, and striking with flow the heated metal bar so as to chill the metal bar to a water temperature. According to the invention, uniformly distributed multi-source microstructure crack groups can be prefabricated for the chipless fine blanking technology of the metal bars with different materials, so that dynamic cracks can be relatively quickly enter an expansion phase in a subsequent blanking process, thereby shortening a whole blanking time and improving an overall blanking efficiency.

Description

technical field [0001] The invention belongs to the technical field of precision blanking of chipless bar stock, and in particular relates to a method for initiating cracks in the microstructure of notched bar stock used for chipless precision blanking. Background technique [0002] Round bar is one of the most basic forms of blanks, and it is widely used, such as various shaft pin parts. The material efficiency and section quality will directly affect the complexity and processing cost of subsequent processes. Using the stress-strain concentration effect of the notch produced by the special geometry of the notch root, the brittleness of the material under high stress triaxiality and the dynamic crack propagation method, the newly developed new chip-free low-stress bar precision blanking technology makes the metal bar The blanking process realizes the real waste-free and material-saving production. However, no matter whether the new type of precision blanking system is dri...

AI Technical Summary

Problems solved by technology

For the new chipless precision blanking technology, the initiation of microstructural cracks mainly comes from the loading of loads, and the distribution and number of microstructural cracks produced by different loading forms are also different. However, limited by the loading form, only It can realize multi-point loading but cannot realize surface loading in the true sense, and only a few microstructure crack sources can be generated at the root of the bar gap

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