A low-stress double-sided high-speed shear method for radially confined metal bars

Abstract

A low-stress double-sided high-speed shearing method for radially constrained metal bars. Before shearing, equidistant annular grooves are processed on the surface of the metal bar, and then the metal bar is fed into the radially constrained double-sided high-speed shearing method. device, so that two adjacent annular grooves are respectively placed between the dynamic shear sleeve, the first static shear sleeve, and the second static shear sleeve, and the high-speed load is applied to the dynamic shear block through the hammer head to realize double-sided shearing of metal bars. Cutting and separation, the invention avoids the horseshoe-shaped collapse caused by the lifting of the metal bar during shearing by radially constraining the metal bar, and at the same time utilizes the stress concentration effect of the annular groove and the embrittlement of the metal material during high-speed shearing effect, higher shear section quality can be achieved at lower shear loads, and overall shear efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of precision blanking of metal bars, and in particular relates to a low-stress double-sided high-speed shearing method for radially constrained metal bars. Background technique [0002] Shearing and blanking of metal bars is the first process for standard parts such as bolts, nuts and pins, various shafts, bushing parts and bearings, gears, chain pins and other commonly used die forgings and cold and hot extrusion parts. Large quantity and wide range. The traditional shearing process at home and abroad uses the movement of the punch to drive the sharp-edged shearing die to achieve a shearing of the metal bar with a large load. During the shearing process, the material in the contact area of ​​the blade tip first undergoes yield deformation and forms a shear collapse angle. Large shear force, "horseshoe-shaped" section collapse, and low weight tolerance accuracy require additional turning processes to flatte...

AI Technical Summary

Problems solved by technology

The traditional shearing process at home and abroad uses the movement of the punch to drive the sharp-edged shearing die to achieve a shearing of the metal bar with a large load. During the shearing process, the material in the contact area of ​​the blade tip first undergoes yield deformation and forms a shear collapse angle. Large shear force, "horseshoe-shaped" section collapse, low weight tolerance accuracy and other problems require additional turning processes to flatten the section, resulting in low production efficiency, high processing costs, and serious waste of materials

[0003] In recent years, the bar fatigue shearing technology developed by using the stress concentration effect of the prefabricated notch and the dynamic crack propagation method has made a new breakthrough in the metal bar shearing and blanking process. Chinese patents 201320338632. The precision blanking method towards low stress bending fatigue fracture has achieved chip-free and material-saving production, but due to the long dynamic crack growth time, the shear efficiency is still difficult to meet mass production

Chinese patents 97119859.4 and 201510304262.1 propose a pre-indentation shearing method, which is characterized in that a certain depth is pre-sheared first, and then the slider moves in reverse to obtain a vertical section of the sheared section. High shear force, difficult to apply to low plastic materials, and prone to chipping

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