The success of a part manufactured through Metal Injection Molding (MIM) does not rely solely on its design or on the primary molding and injection process. To achieve the mechanical properties, strength, and durability required for each application, it is essential to apply a series of heat and surface treatments that enhance the characteristics of the material.
Since 2004, at ALFA MIMTECH we have been offering comprehensive solutions that go beyond manufacturing. We ensure that each part receives the appropriate treatment based on its final application, and we closely supervise all subcontracting processes to guarantee a reliable and consistent results.
Below is an overview of the main heat and surface treatments that form part of our workflow, along with their specific advantages.
- Carburizing + Quenching and Tempering
This treatment is mainly applied to low-carbon steels Carburizing enriches the surface of the part with carbon, achieving high hardness levels, while the core retains toughness and ductility. Quenching and tempering then stabilize the microstructure, ensuring a balance between surface hardness and internal mechanical properties.
Advantages:
- Longer service life of the part.
- Excellent wear and friction resistance.
- Preservation of internal mechanical strength.
- Versatility in automotive sectors, gears, shafts, and precision components.
- Quenching and Tempering
One of the most universal and effective steel treatments Quenching involves heating the material to its critical temperature and rapidly cooling it, which increases hardness Tempering then relieves internal stresses and adjusts hardness, achieving an optimal balance between strength and toughness.
Advantages:
- Excellent impact resistance.
- Precise control of final hardness.
- Flexible application across different steel grades.
- Ideal for tools, machinery parts, and structural components.
- Carbonitriding
Similar to carburizing, but nitrogen is also diffused into the surface The result is a hardened layer that provides greater wear and corrosion resistance compared to traditional carburizing, making it especially suitable for small and medium-sized parts requiring durability.
Advantages:
- Greater resistance to wear and fatigue.
- Improved corrosion resistance compared to carburizing.
- Fast and efficient treatment.
- Ideal for gears, screws, shafts, and transmission elements.
- Annealing
Annealing is designed to soften the material. Through controlled heating and cooling cycles, hardness is reduced, machinability is improved, and the microstructure of the steel is homogenized. It also helps release internal stresses generated in earlier manufacturing stages.
Advantages:
- Facilitates subsequent machining.
- Stabilizes metallurgical structure.
- Improves ductility.
- Fundamental preparatory step in many manufacturing processes.
- HIP (Hot Isostatic Pressing)
Hot Isostatic Pressing combines high temperatures with gas pressure applied uniformly over the part. This treatment reduces or eliminates residual internal porosity and improves density, resulting in a more homogeneous material with superior mechanical properties.
Advantages:
- Increased fatigue and impact resistance.
- Overall enhancement of mechanical properties.
- Reduced risk of internal fractures.
- Key process for critical, high-responsibility parts.
- Normalizing
Normalizing involves heating steel above its critical temperature and allowing it to cool in air. This produces a finer and more homogeneous microstructure, which improves dimensional stability and overall mechanical properties, while preparing the material for further treatments.
Advantages:
- Improved dimensional stability.
- Increased toughness.
- Uniform hardness.
- Ideal base for quenching or carburizing.
- IONIT-OX
This process combines plasma nitriding with a subsequent oxidation step. Nitriding provides surface hardness and wear resistance, while oxidation adds a protective layer against corrosion and gives an attractive satin-black finish.
Advantages:
- High resistance to abrasive and adhesive wear.
- Excellent corrosion protection.
- Enhanced aesthetics with satin-black finish.
- Eco-friendly, generating no toxic waste.
- Gas Nitriding + Post-Oxidation
Nitrogen is introduced into the surface of the part through gaseous atmospheres, followed by controlled oxidation. The result is a harder and more resistant surface, with a protective layer that increases durability in aggressive environments.
Advantages:
- Excellent wear resistance.
- Good resistance to contact fatigue.
- Increased durability in harsh environments.
- Combination of mechanical and chemical resistance.
- Precipitation Hardening
Characteristic of non-ferrous alloys such as aluminum and stainless steels. In the solution stage, alloying elements are dissolved at high temperatures; during precipitation, secondary phases form that significantly increase hardness and strength.
Advantages:
- High mechanical strength in stainless steels.
- Enhanced corrosion resistance.
- Adjustable properties depending on application.
- Widely used in aerospace and biomedical applications.
- Nitrocarburizing
Nitrocarburizing introduces both carbon and nitrogen into the surface simultaneously, but at lower temperatures than carburizing. The result is a thin yet extremely hard layer that increases wear resistance and dimensional stability without causing significant deformation..
Advantages:
- Excellent dimensional stability.
- Low risk of deformation.
- High surface hardness.
- Ideal for small precision parts.
- TENIFER®
Also known as salt bath ferritic nitrocarburizing, TENIFER® produces a compound layer of nitrides and oxides with exceptional hardness. This treatment gives parts a characteristic black finish and ensures a combination of wear resistance, durability, and corrosion protection.
Advantages:
- Excellent wear and corrosion resistance.
- Uniform coating with improved appearance.
- Fast and efficient treatment.
- Common in mechanical components and firearm parts.
- Passivation
Passivation is a chemical treatment mainly applied to stainless steels. By removing contaminants and iron oxides from the surface, it promotes the formation of a stable chromium oxide layer that protects the material against corrosion and keeps it chemically inert.
Advantages:
- Greater durability in aggressive environments.
- Ensures chemical inertness of the material.
- Improves biocompatibility in medical applications.
- Cleaner and more homogeneous finish.
Conclusion
The path to a finished, reliable part made using MIM technology is a long and complex process, in which heat treatments are one of the milestones that will determine the final quality of each project. At Alfa MIMTECH, we have been integrating all phases of the process since 2004, providing real added value to offer our customers the part solutions that best suit their needs.
