Metal sintering is a manufacturing process. By heating a metal powder to a temperature below its melting point, the powder particles are bonded to each other by diffusion. This creates a strong solid object. It is usually not necessary to completely melt the metal during the process. High temperatures and applied pressure are utilised to achieve the bonding between the particles.
Metal Sintering Steps
Metal sintering consists of various types, such as solid state sintering, liquid phase sintering, spark plasma sintering, etc. Each of these methods has specific applications, and SPS has gained attention in recent years because of its rapidity and low temperature characteristics. Although there are many different types of metal sintering processes, their steps are actually very similar.
| Step | Description |
|---|---|
| Powder Selection | Selection of metal powders (e.g. stainless steel | titanium) to determine the properties of the final part. |
| Compaction | Use pressure to compact the powder into the desired shape. |
| Heating | Heating to below melting point in a controlled atmosphere to fuse particles. |
| Cooling and Finishing | Parts are cooled, with minimal finishing if required to achieve near net shape. |
Metal Sintering Applications
Metal sintering is used in several industries because of the ability to produce complex and precise parts. Its versatility lends itself to the rapid, large-scale production of parts with complex geometries or internal features.
- Automotive Industry: Production of gears and bearings.
- Aerospace Industry: Manufacture of turbine blades and high-strength components.
- Electronics Industry: Making electrical contacts and connectors.
- Special: Aircraft hydraulic systems, high-temperature environment filtration materials, etc.
- Others: Filters, fragile shotgun shells, etc.
- Mainly for the manufacture of High-precision and Complex Shaped parts.
Sintered Metal Parts
Materials And Conditions
Suitable materials for sintering include a wide range of metals such as stainless steel, titanium and nickel. Even high melting point metals such as molybdenum and tungsten are suitable for sintering. For high melting point materials, sintering is one of the few viable processing methods. The goal is to achieve very low porosity. Ultra-high temperature sintering (up to 2450-2500°F) can further enhance properties for high strength applications.
Sintering can be static, where metal powders coalesce under specific conditions but return to normal behaviour when removed. It can also involve liquid sintering, particularly in cemented carbides such as tungsten carbide. At least one of the elements is in the liquid state during the process.
Advantages And Benefits
The advantages of metal sintering are numerous. It is particularly suitable for innovative applications in power tool and motor design.
| Advantage | Description |
|---|---|
| High Purity | Fewer steps to maintain material purity. |
| Uniform Porosity | Controllable porosity for specific applications such as filters or bearings. |
| Near Net Shape Production | Minimal finishing required, reducing waste and costs. |
| High Strength Parts | Suitable for highly stressed components such as turbine blades. |
| Versatility | Suitable for complex geometries and mass production. |
Metal sintering has significant advantages in terms of environmental protection and economic efficiency, among others.
Adopting near-net forming technology, the material utilization rate is up to 95% or more. Significantly reduce the ecological damage caused by metal mining.
Reduce 30%-40% of raw material cost compared with traditional cutting process.
Sintering temperatures are typically 200-500°C below the melting point of the metal.Energy consumption is reduced by 15-25%, directly reducing CO₂ emissions.
Energy cost savings can reduce overall production costs by 10-20%.
Direct manufacture of parts containing internal runners or porous structures, reducing subsequent assembly processes and overall energy consumption.
Gears and other complex parts production costs can be reduced by 30%. Reduce assembly time by 50%.
Allows for the blending of 30%-100% recycled metal powder, reducing mineral demand and landfill pollution.
Recycled powder costs 40%-60% less than virgin materials, especially suitable for bulk metal applications such as stainless steel.
Production waste powder can be 100% recycled and reused, avoiding the pollution of oil-containing metal chips produced by traditional machining.
Waste material disposal cost is reduced by 70%-90%.
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