With the development of the machining industry, the production relies on cold work mould manufacturing more and more parts, using more and more types of cold deformation mould. Cold volume die forging (cold upsetting, cold extrusion, embossing, etc.); plate stamping (such as stretching, drop, cutting edge, punching, etc.); material rolling (cold rolling, rolling wheel forming, etc.). Although the cold deformation of a wide range of moulds, working conditions, performance requirements are different, but the basic working situation is similar: that is, in the cold state of the metal deformation, the work of a larger shear force, pressure, bending force, impact and friction. Thus, such mould steel should have the following basic properties:

1) high hardness and high strength, in order to ensure that when subjected to high stress is not easy to produce trace plastic deformation or destruction.

2) high wear resistance, in the high wear conditions can ensure the dimensional accuracy of the mould, this point is more important for the tension die and cold stamping die.

3)Sufficient toughness, so that in the impact load and dynamic load, not easy to work tough spalling or collapse.

4) heat treatment deformation should be small, because most of the moulds have complex cavities and precision, heat treatment deformation is difficult to eliminate by grinding process, in addition some cold deformation moulds should also have sufficient heat resistance.

How to reasonably select the cold deformation of the mould material and appropriate heat treatment means to improve the service life of the mould is the most concerned about the production of the problem, as the cold deformation of the normal failure of the mould should be wear and tear, a small amount of plastic deformation and fatigue failure. However, in actual production, in addition to wear failure, and to collapse tough fracture, cracking and other early failure, it is not uncommon. As we all know, the impact of cold deformation mould service life is a combination of factors; the rationality of raw material selection, raw materials, internal metallurgical quality, design and manufacturing process reasonableness, the use of conditions and the technical level of the operating workers.

Translated with DeepL.com (free version)