As long as small children, the mould is a primary machining tool in many industrial sectors, such as machinery manufacturing, radio meter and electric appliance. Further, human eye the mould has a direct effect on the production cost, accurate output and the quality of the processing technology. Thus, it is quite clear that the quality of the China Extrusion mould should be concerned by people. In recent years people make their effort to research the factors that determine its quality. They find that apart from the proper structure design and processing accuracy the quality of a mould mainly depends on its material and the way of heat treatment.

Owing to the multiple functions of the mould, the working conditions for the moulds are quite several. Therefore, the material for the mould has a broad range of preference. Among so many materials, the mould steel is the most widely used by the mould. Just as its name implies, the so-called Extrusion mould refers to a type of tool steels that are used to make the moulds, such as the cold-punching mould, hot-forging die and so on. According to the functions of the mould steel, it can be grouped into three types, namely cold-working type, hot-working type and plastic type. Now the following article will introduce them in detail.What comes first is the cold-working type. This material is mainly used by the moulds which are suitable to operate in the clod condition. They include cold punching die, cold stamping die, cold extruding die, thread pressing mould, powder pressing mould and so on. The cold-working mould steel is very wide in ranges, from various carbon tool steel, alloy tool steel, rapid tool steel to diverse powder alloy mould steels.

The next type is hot-working Mould steel. This steel is definitely mainly applied in the moulds which are suitable to work in the high-temperature state. Hot-forging mould, hot pressing die, die mould and hot upset forging die are the good example for the above-mentioned mould. There are certain hot-working mildew steels, such as the alloy mould steel with a great amount of carbon and some alloying agents (such as Cr, W, Mo, V and so on). For the special hot-working type, sometimes the austenite heat-proof alloy mould steel will be used.The third type is plastic Extrusion Tooling. Because there are great differences for the requirements of the plastic products, correspondingly there are a lot of requirements for the material of the plastic mould. At present a great number of developed countries have formed the wide range for the steel of the plastic mould. This steel includes the following types, namely carbon construction steel, corrosion-proof type, age hardening type and so on.