How to choose injection molding machine screw? What are the materials of injection molding machine screw? What kind of injection molding machine screw material is durable and not easy to break? Friends who often purchase screws may have such questions, and I believe that the introduction of this article will be helpful to your procurement work.

Injection molding machine screw material material

At present, the screw materials often used in our country are 45 steel, 40Cr, ammoniated steel, 38CrMOAl and so on.

1) No. 45 steel is cheap and has good processing function, but poor wear resistance and corrosion resistance.

Thermal treatment: tempering HB220-270, high-frequency quenching HRC45-48

2) The function of 40Cr is better than that of No. 45 steel, but it is often plated with a layer of chromium to improve its ability to resist corrosion and wear. However, the chromium plating layer has higher requirements, the coating is too thin and easy to wear, too thick, easy to peel off, but accelerate the corrosion after stripping, and it has been less used.

3) Nitride steel, 38CrMoAl comprehensive function ratio is excellent, the application ratio is widespread. The nitriding layer is generally 0.4-0.6 mm. However, this material has a low ability to resist the decay of hydrogen chloride, and the cost is high.

Heat treatment tempering HB220-270, nitriding HRC > 65

Titanium carbide coating is used abroad to improve the corrosion resistance of the screw profile, but it is reported that its wear resistance is not good enough.

In recent years, foreign countries have adopted a series of steps in improving the wear resistance and corrosion resistance of screw. One way is to use highly wear - and corruption-resistant alloy steel. Such as 34CrAlNi, 31CrMo12, etc. Alloy materials with high wear and corrosion resistance are also used to spray the screw profile.

The importance of material selection

The screw is the tension part of the injection molding machine. Its role is to transport, compact, melt, stir and pressure the plastic. All of this is done by rotating the screw inside the barrel.

When the screw rotates, the inner wall of the cylinder, the bottom surface of the screw groove, the thrust surface of the screw edge, and the friction and mutual activity between the plastic and the plastic occur in the city.

The advance of the plastic is the result of this combination of activities, and the heat generated by friction is also absorbed to increase the temperature of the plastic and melt the plastic. The layout of the screw will directly affect the level of these functions.

Therefore, the black and white of the screw material directly affects the function of the injection molding machine, and also directly affects the life of the screw. At present, most of the screws in the sea are imported from abroad, and may be composite materials. Once the sink layer of its profile is cracked, it will cause the entire screw to be scrapped. The performance of domestic screw in extruding ordinary materials is also OK. Once the extrusion has a strong decay product, it can not meet the needs of the industry and mine. Decay is rapid.