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High Efficiency Single Screw Extruder The Screw Area
- Oct 30, 2017 -

High Efficiency Single Screw Extruder The screw area

The development of the screw is the main symbol of extruder, it is the core part of extruder, and it plays an irreplaceable important role for extruder. With the progress and development of science and technology, of screw machinery co., LTD. A lot of theoretical and experimental research, professional custom all kinds of screw, machine is not only a specialized manufacturer of screw, more independent research and development design, and marketing to all over the world. The screw is mainly used in plastic extruder, plastic molding machine and other plastic forming equipment. It is the core part of plastic forming equipment, which is the core of plastic machinery. The screw has a different head, roughly divided into the inner hexagonal screw, the outer hexagon screw, the large flat screw, etc. Extruder is one of the main types of plastic machinery, whether as plastic granulation machinery or molding machine, extruder occupies an important position. The screw has the advantages of high temperature resistance, wear resistance, corrosion resistance, high strength and so on. When they disappear, they can cause serious damage to the screw, so the screw is treated with surface. There are four methods of screw surface treatment.

(1) hard chromium plating

This is an older chemical treatment. The screw material can be used in 40Cr or 45 steel. The screw with hard chromium has good surface finish, strong corrosion resistance and high resistance to wear. The hard chromium plating is currently 0.05 to 0.1mm.

(2) surface flame hardening or high frequency brittle

Surface quenching is a cheap and easy way to handle. The hardness of quenching can reach the HRC55, the quenching depth of 2-3mm. The screw material can be used for 40Cr or 45 steel in flame quenching, so it is economical for large screw. Surface hardening acetylene, propane, available nitrogen, water gas as a fuel, such as the screw heated to 815 ° C). If high frequency quenching is adopted, the quenching frequency should be greater than 4000 hz and then be hardened by water bath or spray.

(3) surface surfacing

The method of surfacing welding and plasma welding can be carried out on the screw. The surfacing alloy can be cobalt base alloy bar (CoCrWMo alloy, such as Reiloyp48 alloy) or ni alloy electrode, the former hardness can reach hrc36-54, the latter can be as hard as hrc52-58. The tungsten carbide can be surfacing directly when the hardness is higher. This process can be used to repair frayed screw, which can be built up to 3mm according to the experience of our country, and the repair cost is 35% to 70% of the new screw.

(4) surface spraying

This is a method that is being vigorously studied at present. The screw material can be used to select the nitride steel, and then spray the special alloy material with a layer of 0.5-0.8mm on the surface of the screw and even the entire screw. In order to further improve the wear resistance, tungsten carbide can be added in the material.