It is mainly used to manufacture punches and dies for blanking and punching metal or non-metal plates. When the sheet is punched between punches and dies, the sheet is deformed at the initial stage. With the increase of the amount of deformation, the lower surface of the sheet is cracked due to the large tensile stress. During use, as the wear of the die and punch increases, the sharp corners of the blade gradually become rounded, resulting in a reduction in the tensile stress on the underside of the sheet, compression in the thickness direction of the sheet, and increased punching The work hardening and deformation of the sheet metal delays the time for the cracking of the sheet metal. After the blank is cut, burrs are generated around the fracture. With the increase of the wear amount of the die, the burr height of the workpiece increases. When the burr height exceeds the specified requirements, the die need to be replaced or repaired.
The steel used for blanking and punching dies is generally selected according to the material type, thickness, batch production of workpieces, dimensional accuracy and shape complexity of the workpiece to be processed.
When punching low-hardness cardboard, plastic plate, aluminum, magnesium alloy plate, and copper alloy plate, if the batch of punched products is not large, carbon tool steel can be used; when the batch is large, low alloys such as CrWMn, 9CrWMn, 7CrSiMnMoV can be selected Steel, quenching and tempering hardness is HRC62~64; the production batch reaches 1 million pieces, steel grades such as Cr12, Cr12MoV, Cr5Mo1V, 7Cr7Mo2V2Si can be selected, and the quenching and tempering hardness is HRC 61 ~ 63; when the production batch exceeds 1 million pieces, High-speed steel, super-hard high-speed steel or cemented carbide can be used to make molds.
For carbon steel plates, silicon steel steel plates and stainless steel plates with high stamping strength and high deformation resistance, high-grade die steel with higher alloy content and better Tang resistance should be selected according to the strength, thickness and deformation resistance of the material.
For molds with larger cross-sectional dimensions, mold steel with high alloying element content and good hardenability should be selected. When the thickness of the processed material increases, it is also necessary to consider the selection of a high-grade mold volume.
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