Sintering Processes and Stages in Metallurgy

May. 13, 24

Sintering is the process of fusing particles into a solid mass by using a combination of pressure and heat without melting the material. Common particles sintered together include metals, ceramics, plastics and a variety of other materials. Vacuum Hot Press Sintering Furnace supplier gives you an overview of how sintering is used in metallurgical processes.

Sintering Processes and Stages in Metallurgy

Sintering Processes in Metallurgy

Most metals can be sintered. Powder sintering is used to improve the strength and structural integrity of metal powders. The sintering process in metallurgy follows the melting of metal powders as well as other materials (e.g., alloying elements) in a single slender furnace using different heat treatment temperature zones. The sintering temperature is always below the melting point of the material to avoid melting. 

The sintering process in metallurgy is divided into three stages.

Initial stage

The first stage of metal powder sintering involves heating the material in the furnace at a temperature rate that induces the production of a martensitic crystal structure. Complete compaction does not occur because the sintering temperature is not sufficient to melt the particles. The material can be consolidated in a number of ways, including using tools to press the material together or using a 3D printing laser that can partially melt the powder.

The particles can also be joined together by cold welding, providing enough strength for the powder briquettes to be used for the rest of the sintering process.


Intermediate processes

The density of the particles increases and they eventually merge. Two common methods to achieve this are transient liquid phase sintering and permanent liquid phase sintering. 

If the sintered powder briquette contains iron, then instantaneous liquid phase sintering is used. In this process, copper powder is added to the iron powder. At normal sintering temperatures, the copper melts and fuses with the iron, hardening the material together. 

In the permanent liquid phase method, liquid materials such as carbide are added and flow into the openings and cracks, further bonding the materials together.

Final stage

By this powder sintering stage, the original sintered powder material has now become mostly in solid form. In the final stage of permanent liquid phase sintering, more liquid and binder additives flow into any open cracks or pores, successfully bonding the filled material together.

Sintering Processes and Stages in Metallurgy

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Uses of sintering

Sintering has several different uses. One of the key uses of sintering is to join metal particles together - sintering is typically used for metals with high melting points because it is not dependent on reaching melting temperatures to work.

Some 3D printing devices create customized forms of metal by sintering one layer of metal at a time. Sintering metal for 3D printing helps save energy compared to melting the same metal, and allows for better control and consistency because the material is not completely liquefied. However, this can leave more microscopic gaps than the full liquefaction caused by melting.

Sintering can also be used to reduce the porosity of an object's surface - which can enhance the properties of certain materials.

Sintering Processes and Stages in Metallurgy

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Sintering and melting key points

Key points to remember about sintering and melting include

Sintering binds materials through heat and pressure, and does not involve melting.

Melting binds particles by heating them until they liquefy and combine into one material.

Sintering can be performed at low temperatures if sufficient pressure is applied.

Sintering is most commonly used to bond high melting point metals and to create custom metal forms using a 3D printer.

Sintering is often used to bond metals and change the physical properties of the material

Interested in sintering processes and furnaces for sintering? Contact HAOYUE today. we have gathered a number of technical elites who have been engaged in the manufacture and service of heat treatment furnace, vacuum furnace and special furnace for a long time.