Three principles of mold material selection

(1) The mold meets the requirements of working conditions

1. Wear resistance

When the blank is plastically denatured in the mold cavity, it flows and slides along the cavity surface, resulting in severe friction between the cavity surface and the blank, resulting in the failure of the mold due to wear. Therefore, the wear resistance of materials is one of the most basic and important properties of molds.

Hardness is the main factor affecting wear resistance. In general, the higher the hardness of mold parts, the smaller the wear, and the better the wear resistance. In addition, the wear resistance is also related to the type, quantity, shape, size and distribution of carbides in the material.

2. Strength and toughness

The working conditions of molds are mostly very bad, and some often bear large impact load, resulting in brittle fracture. In order to prevent sudden brittle fracture of die parts during operation, the die should have high strength and toughness. The toughness of the die mainly depends on the carbon content, grain size and microstructure of the material.

3. Fatigue fracture performance

In the process of die working, fatigue fracture is often caused by the long-term action of cyclic stress. Its forms include small energy multiple impact fatigue fracture, tensile fatigue fracture, contact fatigue fracture and bending fatigue fracture. The fatigue fracture performance of the die mainly depends on its strength, toughness, hardness and the content of inclusions in the material.

4. High temperature performance

When the working temperature of the mold is high, the hardness and strength will decrease, resulting in early wear or plastic deformation and failure of the mold. Because the mold material should have high tempering stability, so as to ensure that the die has high hardness and strength at working temperature.

5. Cold and hot fatigue resistance

Some molds are in the state of repeated heating and cooling in the working process, so that the surface of the cavity is under the action of tensile and pressure strain stress, resulting in surface cracking and peeling, increasing friction, hindering plastic deformation and reducing dimensional accuracy, resulting in mold failure. Cold and hot fatigue is one of the main forms of hot working die failure. This kind of die should have high cold and hot fatigue resistance.

6. Corrosion resistance

When some molds such as plastic molds are working, due to the presence of chlorine, fluorine and other elements in the plastic, they decompose and precipitate HCI, HF and other strong corrosive gases after heating, which erode the surface of the mold cavity, increase its surface roughness and aggravate wear failure.

(2) The mold meets the process performance requirements

The manufacture of molds generally goes through several processes such as forging, cutting and heat treatment. In order to ensure the manufacturing quality of the mold and reduce the production cost, the material should have good malleability, machinability, hardenability, hardenability and grindability; It should also have small oxidation, decarburization sensitivity and quenching deformation cracking tendency.

1. Malleability

It has low hot forging deformation resistance, good plasticity, wide forging temperature range, low tendency of forging crack, cold crack and precipitation of network carbide.

2. Annealing processability

The spheroidizing annealing temperature range is wide, the annealing hardness is low and the fluctuation range is small, and the spheroidizing rate is high.

3. Machinability

Large cutting parameters, low tool loss and low machining surface roughness.

4. Oxidation and decarburization sensitivity

When heated at high temperature, it has good oxidation resistance, slow decarburization speed, insensitive to heating medium and small tendency to produce pitting.

5. Hardenability

After quenching, it has uniform and high surface hardness.

6. Hardenability

After quenching, a deep hardening layer can be obtained, and it can be hardened with mild quenching medium.

7. Quenching deformation and cracking tendency

Conventional quenching has small volume change, slight shape warpage and distortion, and low tendency of abnormal deformation. Conventional quenching has low cracking sensitivity and is not sensitive to quenching temperature and workpiece shape.

8. Grindability

The grinding wheel has small relative loss, no burn limit, large grinding amount, insensitive to grinding wheel quality and cooling conditions, and is not prone to abrasion and grinding cracks.



About Huizhou Dj Molding Co., Ltd

Dj Mold is a China mold maker of plastic molds- injection mold, die casting moulds, plastic blow molding, rotational molding, medical plastic injection molding, two shot plastic injection molding, insert molding, overmolding, metal injection molding, micro injection molding, powder injection molding, ceramic injection molding, liquid injection molding, husky injection molding, household mold, casting mold, die mold tool, custom molds, china moulds, rapid prototyping tooling, plastic prototyping tooling, punch press tooling, die and tooling for mobile/ cell phone parts, automotive parts, vacuum cleaners, rechargeable tools, telephones, copiers, computers, multimedia speakers, and many other electronic products and household appliances. And also a plastic product manufacturer, mold manufacturer China– plastic parts, plastic water tank, plastic balls, plastic containers, plastic buckle, plastic anchor, plastic hanger, plastic spoon, plastic pipe fitting, plastic tumble, plastic tableware, plastic cups, plastic bottles, plastic tray, plastic cosmetic container, plastic case, plastic food container, plastic chairs, plastic caps, plastic cap closure, plastic tubes, plastic water pipes, plastic knobs, plastic tubing, plastic utility boxes, plastic racks and so on.

Person: James Yuan
Company: Huizhou Dj Molding Company Limited
Add:  LongGang Village,LongXi Town,BoLuo County,HuiZhou City,GuangDong Province, China
Tel: 86-752-6682869
Email: [email protected]


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