Sintering process of MIM

Sintering process of MIM

Let us continue to introduce every process of Metal Injection Molding technology.

Today we will discuss about the sintering which is the most important points during MIM.



1) Sintering is to heat and hear the powder compact at a temperature lower than the melting point of its main components, and then cool it in a certain way and speed, thereby improving the strenth and various physical and mechanical properties of the compact and obtaining a certain metallographic structure.

2) The basic process is Powder compact–Furnace Charging–Sintering including Preheating, Heat Preservation and Cooling–Firing–Sintered products.

3) The function of sintering is get lubricant removal, metallurgical bonding, element diffusion, dimensional changes, microstructure and ocidation prevention.



1) Low temperature Pre-sintering stage:

In this stage, the recovery of metal, volatilization of adsorbed gas and moisture, decomposition and removal of forming agent in the compact.

2) Intermediate temperature heating sintering stage:

Recrystallization begins at this stage. First, the deformed crystal grains are restored within the particles and reorganized into new crystal grains. At the same time, the oxides on the surface of the particles are completely reduced, and the particle interface forms a sintering neck.

3) High termperature hear preservation to complete the sintering stage:

This stage is the main process of sintering, such as diffusion and flow fully proceeding and close to completion, forming a large number of closed pores, and continuing to shrink, so that the pre size and total number of pores are reduced, and the density of the sintered body is significantly increased.

4) Cooling stage:

The actual sintering process is continuous sintering, so the process from the sintering temperature to slow cooling for a period of time and then rapid cooling until the furnace output reaches room temperature is also a stage where austenite decomposes and the final structure is gradually formed.

There are many influencing factors to affect the sintering process. And the factors including temperature, time, atmosphere, material composition, alloy method, lubricant content and sintering process such as heating and cooling rate. It can be seen that each linke has an important influence on the quality of sintering. For products with different structures and different powders, different parameters need to be adjusted.

Post time: Jan-15-2021