What is carbide cold heading die
Tungsten carbide cold heading die is a high-hardness, high-strength alloy material that is pressed and sintered by powder metallurgy. Under the action of impact, a metal bar is cold-deformed in the mold cavity. It is widely used in production In the processing field, the cold heading die is mainly used for the parts that directly contact the workpiece. The hard alloy is used as the core die to be pressed into the steel material jacket, which is more wear-resistant and more efficient, and the service life is increased by ten to tens of times.
Working conditions carbide cold heading die: Under strong impact force, the impact pressure stress of the punch can reach more than 2500MPa, the surface of the concave die and the working surface of the punch are both subjected to severe impact friction, and the temperature generated on the surface is as high as 300℃. Due to the unequal end faces of the blank, the punch will also be subjected to bending stress. Cold heading dies under impact or strong impact wear-resistant working conditions, their commonality is that the cemented carbide has good impact toughness, fracture toughness, fatigue strength, bending strength and good wear resistance. So many fasteners are formed by cold heading dies.
The main failure modes of hard alloy cold heading die are: excessive wear on the working surface of the convex and concave die, occlusal damage, local groove peeling, upsetting or breaking of the punch, swelling or cracking of the die, collapse of edges and corners, etc.
Its performance requirements: the cold heading die bears the impact load generated by the heading, and the working surface of the die is required to have high hardness and wear resistance, and the core has sufficient strength and toughness. If the hardened layer of the cold heading die is too hard or too deep, the mold parts will be broken; on the contrary, the working surface of the mold parts is easy to wear and the rough material adheres to the mold parts. Usually the hardness of the punch is 60~62HRC, the hardness of the die is 58~60HRC, and the depth of the hardened layer should be controlled within 1.5~4mm. The cold heading die is subjected to severe stamping loads, and the surface of the die is subjected to high compressive stress. The mold material is required to have high strength, toughness and wear resistance.
After tugnsten cold heading die is heat treated, the surface must have high hardness and the core must have good toughness, so that a certain compressive stress on the surface can offset the stress suffered during the cold heading process.
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