Plastic mold steel should have performance
1.1 Plastic mold steel use performance
Hardness is an important performance indicator required by the mold, and the mold should be able to maintain its size under the action of pressing force.
And the shape does not change rapidly to keep the precision and usability of the mold. Therefore, the molded mold should be
Sufficient hardness to ensure that the mold has sufficient stiffness.
2. Wear resistance
The mold is in the work due to the filling and flow of plastics to withstand considerable compression stress and friction, and require the mold in this
The size and shape can still be kept unchanged under conditions, and ensure that the mold has sufficient service life, especially in shaping hard plastics or
There is a high demand for wear resistance when there is glass fiber reinforced plastics. The wear resistance of the mold depends on the components of the steel used.
Weaving and heat treatment hardness. Therefore, the hardness of improving the mold is advantageous to improve its wear resistance. But after the hardness reaches a certain value, hard
The effect of degree on wear resistance becomes not very obvious
3. Strength and toughness
The mold should bear the impact, bending and shear stress in the work, and the work is often caused by its intensity and toughness.
Damage (local or large damage). Therefore, make the mold have sufficient strength and toughness facilitates the prolonging mold life and protect
Secure usage security.
Steel grain size and the number, size and distribution of carbides in steel, and the amount of steel, the strength and toughness of steel
Sexual impact. As the increase in grains in the steel and the increase in the unevenness of the carbide distribution, the strength of the steel decreases, and at the same time
Its toughness also has an adverse effect. Therefore, according to the conditions of use conditions and performance requirements, the chemical structure of the mold steel is rationally selected.
Division, organizational state and heat treatment process can reach the mold on its strength and toughness.
4. Corrosion resistance
When a plastic article of forming polyvinyl chloride or an additive such as a flame retardant is decomposed in the thermoforming process
Corrosion gas, has a strong corrosion effect on the mold. Therefore, in addition to the mold, mold material for producing such plastic products,
It is necessary to have certain hardness, strength, and wear resistance, while having certain corrosion resistance.
1.2 Workability of plastic mold steel
Processability refers to cold-machining and etching and processing performance of forging, heat, processing performance and cutting, grinding, and other forms.
The mold especially considers its polishing performance. These properties and steel chemical composition, smelting quality, tissue state, sulfur, phosphorus
The content is related.
2. Heat treatment deformation
The mold size and shape requirements are strict, and the mold requires the size of the mold when the mold is finally treated after finishing.
The change in shape is small as possible, so the modifications required for the mold material are small in heat treatment, while it is sufficient.
Width quenching temperature range to reduce incumbent in superheating or quenching temperature .
3. Hardness and hardenability
The hardenability is mainly related to the chemical composition of steel, especially carbon content. In addition to the chemical composition of steel, hardenability is also related to the chemical composition of steel.
Related to the original tissue before quenching. According to the condition and function of the mold, the requirements for hardening and hardenability
There is a focus.
4. Decarburizing sensitivity
Decarburization in the mold surface during heat treatment, which reduces the mechanical properties of the surface layer of the mold, especially the abrasion resistance of the surface. Therefore, the decarburization sensitivity of the mold steel is required to be soaked.