Choose Steel For Cold Heading Dies

A lot of fasteners are formed by cold heading dies. The cold heading dies have been born violent punching loads. The concave die surface is under high stress. So the high stress could offset the stress which produced during the cold heading process.

Generally speaking, cold heading dies which used for small quantities of workpiece usually choose carbon tool steel or low alloy cold die steel. The mold cavity surface must be done local quenching. And making the hardness of cavity surface reach to HRC60. But the die central should reach to the range from HRC35 to HRC45. Certainly people would choose die steel by its section size. Besides it owns hardenability. Too shallow hardened layer is easy to result in cavity collapse. On the contrary, too deep hardened layer may make the die cracking.

Some cold heading dies need long service time. These one are often adopt high alloy die steel or high speed steel. In order to make the die could bear high impact load, we can use combined die structure. Cold heading dies with high hardness are made of die material which is in high alloy. Making cold or hot pressing method inserts into the outer sleeve. Then they will be contacting closely.