Tool stability under cold stamping of rod parts and hardware

The results оf compressive strength tests of many structural and tool steels used for cold heading are listed. It is shown that the initial factor determining tool stability is the ratio of the tool strength to the stamped part strength. While calculating die tooling it is necessary to know the tool ultimate compressive strength, though known literature lists only hardness (HRC 60-62). Table conversion of hardness to ultimate strength is single-valued for all tool steels. But in practice considerable difference in strength properties while hardening the tool is possible in spite of stable hardness. This indicates the importance of this study. The work is carried out with the help of the versatile testing facility. The samples under compression test were 10 mm in height, 5 mm in diameter and were supported on strong wide pads.