Carbide punch diesis a special process equipment which is used to process materials (metal or nonmetal) into parts (or semi-finished products) in cold stamping process, which is called cold stamping die (commonly known as cold carbide dies). Stamping is a pressure processing method to obtain the required parts by pressing the material at the room temperature with the die installed on the press so that it can produce separation or plastic deformation. This paper introduces the selection of stamping die material and the influence of die manufacturing process on the service life of carbide punch dies.

Selection of blanking die materials

The blanking die material should consider batch workpiece production, if the volume is not high there is no need to select the life of die material; should also consider washed workpiece materials, different materials for the mould materials are also different. For punching die, wear resistance is an important factor in determining the die life, depends on the wear resistance steel carbide in hard phase condition and matrix hardness, both higher hardness, the more the number of carbide is better wear resistance. The inferior and common stamping die steel wear resistance are carbon tool steel alloy tool steel - steel - steel - Gao Tangao matrix of high speed steel - steel bonded carbide - tungsten carbide.

In addition, the influence of the thickness, shape, size and precision requirement of the workpiece on the choice of the mould material must be considered.

1. traditional die steel, for a long time, the domestic sheet blanking die steel for T10A, CrWMn, 9Mn2V, Cr12 and Cr12MoV, etc..

Among them, T10A is carbon tool steel, with certain strength and toughness. But the wear resistance is not high, the quenching is easy to deformation and cracking, hardenability is poor, only suitable for the workpiece shape is simple, small size, small number of blanking die.

The heat treatment process of T10A carbon tool steel is: 760~810 degree of water or oil quenching, tempering at 160~180, hardness 59~62HRC.

CrWMn and 9Mn2V are high carbon and low alloy steel. Quenching is easy to operate, hardenability is better than carbide punch dies, deformation is easy to control. But the wear resistance and toughness are still low, and it is applied to the medium batch, the workpiece shape is more complex blanking die. The heat treatment process of CrWMn steel is as follows: quenching temperature 820~840, oil cooling, tempering temperature 200, hardness 60~62HRC. The heat treatment process of 9Mn2V steel is as follows: quenching temperature 780~820, oil cooling, tempering temperature 150~200, air cooling, hardness 60~62HRC. Attention should be paid to tempering brittleness and significant volume expansion at tempering temperature range of 200~300.

Cr12 and Cr12MoV for high carbon high chromium steel, high wear resistance, quenching deformation is small, good hardenability, mold used for mass production, such as carbide punch dies. However, the carbide of this kind of steel is uneven, easy to produce carbide segregation, and it is easy to break or break during cutting. Among them, carbon content of Cr12 is higher, carbide distribution is more serious than Cr12MoV, brittleness is greater.

Require the use of the heat treatment process of Cr12 steel depends on the choice of the mold, when the mold requirements relatively small deformation and toughness, the low temperature quenching and tempering (Cr12 950~980 DEG C for quenching, tempering; 150~200 C Cr12MoV 1020~1050 C 180~200 C quenching, tempering). If you want to improve the temperature of the mold, improve its hardenability and hardness, can be made of high temperature quenching and tempering (Cr12 1000~1100 DEG C for quenching, tempering; 480~500 C Cr12MoV 1110~1140 C 500~520 C quenching, tempering).

High chromium steel is temper brittleness in the 275~375 C region should be avoided.

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