Types of Iron-Based Powder Metallurgy Materials

Introduction

Iron-based powder metallurgy (PM) materials represent the most widely used category in the PM industry, thanks to their low cost, good formability, and adaptability across diverse applications. These materials can be systematically classified based on their alloy systems, intended applications, and forming technologies. Below is an organized overview of common classifications and typical material grades.

1. Classification by Alloying Elements

1.1 Pure Iron (Fe)

The most basic iron powder used as a base material or for structural parts.

• Features: Low cost, good plasticity, suitable for Fe-based carbon or copper alloys.

1.2 Iron-Carbon Alloys (Fe-C)

Formed by adding graphite to create low-alloy steels (e.g., Fe-0.8%C).

• Applications: Self-lubricating bearings, structural parts.

1.3 Fe-Cu Alloys

Improve electrical conductivity, strength, and formability.

• Applications: Power tool parts, friction plates.

1.4 Fe-Cu-C (Iron-Copper-Carbon) Alloys

One of the most common structural PM materials.

• Features: Balanced mechanical performance; cost-effective for structural components.

1.5 Fe-Ni, Fe-Mo, Fe-Cr Alloys

Adding elements like nickel, molybdenum, and chromium enhances hardness, strength, and corrosion resistance.

• Applications: High-performance structural parts, heat-treatable components.

1.6 Stainless Steel-Based Powders (Fe-Cr-Ni-Mo)

Grades include 304L, 316L, 410L.

• Applications: Corrosion-resistant parts, automotive exhaust components, instrument housings.

2. Classification by Application

2.1 Structural Materials

Focused on strength, rigidity, and dimensional stability. Commonly use Fe-C or Fe-Cu-C.

• Applications: Automotive gears, bushings, pump impellers, locks.

2.2 Friction Materials

Contain Fe, Cu, and graphite for high friction coefficient and thermal stability.

• Applications: Brake pads, clutch plates.

2.3 Oil-Impregnated Bearing Materials (Self-Lubricating)

Mainly Fe-Cu based, with graphite added and porous processing applied.

• Applications: Motors, household appliances, rotating tool components.

2.4 Magnetic Materials

Includes soft magnetic composites like Fe-Si, Fe-P systems, and ferrites.

• Applications: Inductors, motors, transformer cores.

2.5 Wear-Resistant/Corrosion-Resistant Materials

Enhanced with Cr, Mo, Ni, Co for performance under harsh environments.

• Applications: Valves, pump housings, components exposed to high temperature or humidity.

3. Classification by Forming Process Compatibility

3.1 Press and Sinter PM Materials

Mostly low-alloy Fe-based powders for traditional press + sinter processes.

3.2 MIM-Compatible Materials (Metal Injection Molding)

Use ultra-fine powders (D50: 10–20μm), such as Fe-2Ni, 17-4PH.

• Features: Excellent flowability and uniform shrinkage during sintering.

3.3 AM-Compatible Powders (Additive Manufacturing)

Iron-based powders for 3D printing, including 316L, 18Ni300, H13.

Typical Grades of Iron-Based PM Materials

Conclusion

Iron-based powder metallurgy materials offer wide adaptability across applications ranging from structural and magnetic components to high-strength and corrosion-resistant parts. As technology evolves in fields such as MIM and additive manufacturing, the diversity and functionality of Fe-based PM materials continue to expand, driving innovation in precision and high-volume production.