What are the principles for selecting mold materials

Release time:

2022-05-13

Some molds are in a state of repeated heating and cooling during the working process, causing the surface of the mold cavity to be subjected to tensile and compressive stress, resulting in surface cracking and peeling, increasing friction, hindering plastic deformation, reducing dimensional accuracy, and ultimately leading to mold failure. Cold and hot fatigue is one of the main forms of failure in hot working molds, and such molds should have high resistance to cold and hot fatigue.

What are the principles for selecting mold materials

Principles for selecting materials in Moxian County
Some molds are in a state of repeated heating and cooling during the working process, causing the surface of the mold cavity to be subjected to tensile and compressive stress, resulting in surface cracking and peeling, increasing friction, hindering plastic deformation, reducing dimensional accuracy, and ultimately leading to mold failure. Cold and hot fatigue is one of the main forms of failure in hot working molds, and such molds should have high resistance to cold and hot fatigue.

（1） Corrosion resistance
Some molds, such as plastic molds, when working, due to the presence of elements such as chlorine and fluorine in the plastic, will decompose strong corrosive gases such as HCI and HF after being heated, corroding the surface of the mold cavity, increasing its surface roughness, and intensifying wear and failure.

（2） Meet process performance requirements
The manufacturing of molds generally involves several processes such as forging, cutting, and heat treatment. To ensure the manufacturing quality of molds and reduce production costs, their materials should have good malleability, machinability, hardenability, hardenability, and grindability; It should also have a small sensitivity to oxidation, decarburization, and a tendency towards quenching deformation and cracking

1. Forgeability
Has low resistance to hot forging deformation, good plasticity, wide forging temperature range, low tendency for forging cracking, cold cracking, and precipitation of network carbides.

2. Annealing processability
Spheroidization annealing has a wide temperature range, low annealing hardness and small fluctuation range, and high spheroidization rate.

3. Machinability
The cutting amount is large, the tool loss is low, and the machining surface roughness is low.

4. Sensitivity to oxidation and decarbonization
When heated at high temperatures, it has good antioxidant capacity, slow decarburization speed, is not sensitive to the heating medium, and has a small tendency to produce pitting.

5. Hardenability
After quenching, it has a uniform and high surface hardness.

6. Hardenability
After quenching, a deeper hardening layer can be obtained, which can be hardened using a mild quenching medium.

7. Quenching deformation and cracking tendency
Conventional quenching has small volume changes, slight shape warping and distortion, and low tendency for abnormal deformation. Conventional quenching has low sensitivity to cracking and is not sensitive to quenching temperature and workpiece shape.

8. Grindability
The grinding wheel has relatively low wear and tear, with no burn limit. It is not sensitive to the quality and cooling conditions of the grinding wheel, and is less prone to abrasion and grinding cracks.
（3） Meet economic requirements
When selecting materials for molds, the principle of economy must be considered to minimize manufacturing costs as much as possible. Therefore, on the premise of meeting the performance requirements, the first choice is to use lower priced materials. If carbon steel can be used, alloy steel is not needed, and if domestic materials can be used, imported materials are not needed.

What are the principles for selecting mold materials

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