Because the failure of the drawing die is mainly adhesive wear and abrasive wear, and mainly adhesive wear. Therefore, the selected mould material must have high wear resistance and anti-adhesion performance, and sufficient strength. The selection should also consider factors such as the thickness of the sheet material to be drawn, the size and shape of the drawn part, and the size of the production batch.
(1) Die materials for light-load drawing (thin steel sheet and copper, aluminum alloy)
When the production batch is small, T8 and T10 steels can be selected for simple cylindrical shallow drawn parts; for small and medium-sized parts with complex shapes, CrWMn and 9Mn2V can be selected.
For medium batch production or large production batches, Cr12MoV is used.
When the production volume is large, use cemented carbide or steel-bonded cemented carbide.
(2) Die material for heavy-duty deep drawing (thick steel drawing, reverse drawing, thinning and deep drawing)
When the production batch is small, T10 and CrWMn can be selected.
When the production volume is large, Cr12MoV and GM steel are used. The strength and toughness of GM steel are higher than that of high-speed steel and Cr12MoV; its anti-adhesive wear and abrasive wear resistance are significantly better than that of base steel and Cr12MoV, and it has been well used in drawing dies.
When the production volume is large, consider using cemented carbide or steel-bonded cemented carbide.
(3) Die materials for drawing stainless steel, high nickel alloy steel, and heat-resistant steel plate
When this type of material is drawn, adhesion and napping are prone to occur, and the preferred mould material is aluminum bronze.
When the production volume is small, you can choose aluminum bronze, T10A (hard chrome plating, pay attention to the plating layer should not be too thick when using the hard chrome plating process to prevent peeling off during deep drawing).
When the production volume is large, choose aluminum bronze, Cr12MoV, Cr12Mo1V1 (surface nitriding).
When the production volume is large, cemented carbide is used.
(4) Drawing die materials for large deep drawing parts and automobile covering parts
Can choose alloy cast iron or high-strength ductile iron. Nodular cast iron can be immersed in lubricating oil, and the graphite in the structure has a self-lubricating effect, which can effectively reduce the friction in deep drawing, and has low cost and easy processing.
High-strength nodular cast iron can be austempered with dual-medium delayed cooling martensite to obtain higher strength and toughness, with a hardness of 55~58HRC. Slowly preheat the mould first and then heat it to 880~900℃. After heat preservation, it will be air-cooled first, then the salt water will be quenched to about 550℃ and then it will be transferred to oil cooling. Keep the hot oil at a temperature of ℃ for 2~3 hours, then reduce the oil temperature to about 170℃ and wait for 5~7 hours, and finally transfer to air cooling.