Plastic mold manufacturer Selection of steel for manufacturing

Plastic mold The selection of steel can be divided into the following four situations:

1、 Cold working die with small size, simple shape and light load

For example, small punches and scissors for cutting off steel plates can be made of carbon tool steels such as T7A, T8A, T10A and T12A. The advantages of this type of steel are:; Good processability, low price and easy source. However, its disadvantages are low hardenability, poor wear resistance and large quenching deformation. Therefore, it is only suitable for manufacturing tools with small size, simple shape and light load, as well as cold image molds that require not deep hardening layer and maintain high toughness.

2、 Cold working die with large size, complex shape and light load

The commonly used steels are low alloy cutting tool steels such as 9SiCr, CrWMn, GCr15 and 9Mn2V. The quenching diameter of these steels in oil can be more than 40 mm on the whole. Among them, 9Mn2V steel is a kind of cold work die steel without Cr developed in China, which can replace or partially replace the steel containing Cr.

9Mn2V steel can be quenched in the quenching medium with moderate cooling capacity, such as nitrate and hot oil. Austenitic isothermal quenching can be used for some dies with strict deformation requirements and low hardness requirements.

3、 Cold working die with large size, complex shape and heavy load

Medium alloy or high alloy steel must be used, such as Cr12Mo, Crl2MoV, Cr6WVCr4W2MoV, etc. In addition, high-speed steel is also used.

When high-speed steel is used as cold die, low temperature quenching shall be adopted to improve toughness. For example, when W18Cr4V steel is used as cutting tool, the commonly used quenching temperature is 1280-1290 ℃. When making cold working dies, 1190 ℃ low temperature quenching shall be adopted. Another example is W6Mo5Cr4V2 steel. After low temperature quenching, the service life can be greatly improved, especially the fracture rate can be significantly reduced.

4、 Cold working die with impact load and thin tool spacing

As mentioned above, the performance requirements of the first three types of steel for cold working dies are mainly high wear resistance. Therefore, high carbon hypereutectoid steel and even ronstite steel are used. However, for some cold working dies with trimming floor and blanking die, their butt joints are thin, and they are subject to impact load when in use, so high impact toughness is required.