What Are the Properties of Cold Work Die Steel when Used?

With the development trend of industrial production, many products are slowly coming out, using various shapes and carrying out production and manufacturing in different conditions. Cold work die steel refers to die steel used to deform or shape metal materials under cold conditions.

Since most of the cold work dies work at room temperature, the plastic deformation resistance of the raw materials is large, the die work stress is large, and the working conditions are severe. Therefore, the comprehensive performance requirements of this type of die are generally high, and the strength and wear resistance are good. Besides, it has adequate compressive strength and appropriate toughness. Let's give you a detailed introduction to the performance of cold work die steel. I hope it would be helpful!

1. High wear resistance of cold work die steel

(1) When the cold work die is working, there are many frictions between the surface and the blank. In this case, the die must still maintain a low surface roughness value and high dimensional accuracy to prevent early failure.

(2) Since the hardness and structure of the die material are important factors affecting the wear resistance of the die, in order to improve the wear resistance of the cold work die, the die hardness is usually required to be 30% to 50% higher than the hardness of the workpiece. And the structure of the material is tempered martensite or lower bainite, on which fine granular carbides are evenly distributed. To achieve this goal, the mass fraction of carbon in cold work die steel is generally above 0.60%.

2. Higher strength and toughness of cold work die steel

The strength of the die refers to the ability of the die parts to resist deformation and fracture during the working process. Strength index is an important basis for the design and material selection of cold work die, mainly including tensile yield point, compression yield point and so on.

Yield point is an index to measure the plastic deformation resistance of die parts, and it is also the most commonly used strength index. In order to obtain high strength, in the die manufacturing process, the toughness of the die material must be determined according to the working conditions of the die. For dies with strong impact loads, such as the terrace die of cold work dies, cold heading dies, etc., due to impact load Larger, high toughness is required.

For cold work die steel under general working conditions, it is usually subjected to multiple impact loads with small energy. The failure mode of the die is fatigue fracture, so the die is not required to have an excessively high impact toughness value.

3. Cold work die steel has strong seizure resistance

The seizure resistance is actually the resistance to "cold welding". Usually under dry friction conditions, the tested die steel sample and the material with the tendency of seizure (such as austenitic steel) are subjected to a constant-speed dual friction movement, and the load is gradually increased at a certain speed. At this time, the torque is also corresponding increased.

When the load increases to a certain critical value, the torque increases suddenly and sharply, which means that seizure occurs. This load is called "seizure critical load". The higher the critical load, the stronger the seizure resistance.

4. The heat softening ability of cold work die steel

The heat softening ability reflects the influence of the temperature rise of the cold work die steel on the hardness, deformation resistance and wear resistance during load. The main indicators that characterize the softening resistance of cold work die steels are softening temperature (℃) and secondary hardening hardness (HRC).

The above is the relevant introduction of the performance of cold work die steel. If you want to know more about cold work die steel, you can pay more attention to our official website!

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