Sintering process of tungsten steel punch

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Tungsten steel punch sintering molding is to press the powder into billet, then into the sintering furnace heating to a certain temperature (sintering temperature), and maintain a certain time (holding time), and then cool down, so as to obtain the required function of tungsten steel punch.The sintering process of tungsten steel punch can be divided into four fundamental periods:

1: Removal of forming agent and pre-burning period

During this period, the sintered body occurs, the removal of molding agent, the initial stage of sintering with the increase in temperature, molding agent gradually decomposition or vaporization, cleaning out the sintered body, at the same time, molding agent more or less to the sintered body carbon, carbon increase will be different with the type of molding agent, quantity and sintering process.

Tungsten steel punching powder appearance oxide is restored, at the sintering temperature, hydrogen can restore cobalt and tungsten oxide, if the vacuum removal molding agent and sintering, carbon and oxygen reaction is not strong.The contact stress between the powder particles was gradually eliminated, the bonding metal powder began to recover and recrystallize, the appearance of dispersion began to attack, the strength of the block has improved.

2: Solid phase sintering period (800℃- eutectic temperature)

At the temperature where the liquid phase once was, the solid phase reaction and dispersion were aggravated, the plastic flow was strengthened, and the sintered body was obviously shortened.

3: During liquid phase sintering (eutectic temperature-sintering temperature)

When the sintered body presents a liquid phase in the future, shortening is soon completed, followed by crystallization changes, forming the fundamental arrangement and structure of the alloy.

4: During cooling (sintering temperature – room temperature)

During this period, the arrangement and phase composition of tungsten steel punch change with different cooling conditions. This feature can be used to conduct heat treatment on tungsten steel punch to improve its physical and mechanical functions.