Tungsten Carbide Extrusion Thermoplastic Forming Agent

Tungsten carbide extrusion thermoplastic forming agent is the most common forming agent system during the process of tungsten carbide extrusion thermoplastic forming. It mainly takes thermoplastic organics as the main body, which can be divided into ceryl, oil base, plastic base and other types. Compared with other types, the research to ceryl forming agent is much mature.

Classification of Extrusion Thermoplastic Forming Agent
Extrusion thermoplastic forming agent takes thermoplastic organics as forming agent body. Based on the forming agent body, extrusion thermoplastic forming agent can be divided into ceryl system, oil base system and Plastic base system, etc.So far, the research to ceryl forming agent has been much mature, which become the most competitive forming agent. Ceryl forming agent includes paraffin, Polyethylene wax, carnauba wax, lignite wax, liquid paraffin and microcrystalline wax (as shown below); oil base forming agent mainly contains vegetable oil (peanut oil, coconut oil, etc),and mineral oil, etc. Plastic base forming agent mainly include high density polyethylene, Low Density Polyethylene, linear low density polyethylene, polypropylene, polystyrene, EVA, ethylene propylene rubber, etc.

Features of Different Kinds of Thermoplastic Forming Agent
Compared with ceryl forming agent, oil base forming agent has low viscosity and good liquidity due to it is in liquid state or in semi-solid state at room temperature. There are also many disadvantages, for instance, it is easy to volatilize under mixing process, easy to separate the two phases in the extrusion process, low squeeze billet strength, poor conformality, swelling easily when solvent degreasing and stress cracks.

The oil employed frequently in oil base forming agent is hydrogenated vegetable oil or coconut oil. Plastic base macromolecule aims to enhance the strength of green body extrusion. Therefore, the proportion of macromolecule increases, but the degree of polymerization of macromolecule used in forming agent is low in general to assure lower melting point and lower viscosity. Plastic base forming agent has a good conformality, but it has a low powder carrying capacity and slow degreasing.

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