Hi,friends!We are a professional powdered metal parts manufacturers in China. We have a lot of powder metallurgy sintering of the components. As a powder metallurgy manufacturer I will tell you how issintering process in powder metallurgy!
Sintering process in powder metallurgy undergoes a series of physical and chemical changes, such as water or organic evaporation or volatilization, adsorption gas purging, the elimination of stress, the powder particle surface oxide reduction, intergranular material migration, recrystallization and grain growth, thus make crystal interface between particles increases, the pore shrink or even disappear. When the liquid phase appears, the dissolution and precipitation of the solid phase will also occur. These processes do not have clear boundaries with each other, but overlap and influence each other. In addition to other sintering in metallurgy, the reaction of the whole products made by powder metallurgy is complicated. In 1942, German G.F. Schutig used physical and chemical research methods to measure the influence of sintering temperature on electromotive force, solubility, density, microstructure, mechanical properties of sintered body, and found that sintering is a very complex process. In 1949, G.C.Kuczynski of the United States studied the sintering of metal balls and metal plates and believed that the material migration during sintering was mainly carried out by diffusion. Their work pushed the study of sintering theory to a new stage. Much of the subsequent research work has focused on the mechanism of material migration during sintering.
It is generally believed that there are five mechanisms of material migration during sintering: viscous or plastic flow, evaporation and condensation, volume diffusion, grain boundary diffusion, and surface diffusion. When two spherical particles in contact are sintered, the growth of contact neck radius X may be related to the sintering time t as follows:
Sintering process Sintering must be carried out in a sintering furnace with a protective atmosphere to avoid oxidation of the sintered body or adverse chemical reactions. There are many kinds of sintering furnaces, which can be used as heat sources such as natural gas, gas, oil and electricity. Electric heating furnace is economical and convenient, easy to adjust and control. The commonly used protective atmosphere is vacuum, argon, helium, nitrogen, carbon dioxide and other inert gases and hydrogen, decomposition of ammonia, carbon monoxide, conversion of natural gas and other reducing gases.
In order to further improve the performance of sintered products and size and shape accuracy, it is often necessary to carry out shaping, finishing, repressing, oil immersion, mechanical processing, heat treatment and other subsequent processes.
Injection molding process flow
Post time: Jul-29-2022