Metal Injection Molding（MIM）Materials

Metal Injection Molding (MIM), also called metal injection moulding or powder injection moulding (PMIM), produces small, complex metal parts with high precision. Engineers mix metal powders with binders, inject them, then debind and sinter the parts using various Metal Injection Molding (MIM) Materials to create strong, high-performance components.high-performance components. This metal injection molding process allows for mass production of intricate components that would be difficult or costly to make with traditional machining.Engineers use metal injection molding (MIM) materials like steel, titanium, and micro metals to create durable, high-performance parts with excellent repeatability, corrosion resistance, and surface finish for industrial, medical, and consumer applications.

Why Is Metal Selection Crucial in the MIM Process?

Choosing the right Metal Injection Molding (MIM) Materials is critical, as they determine part performance, strength, corrosion resistance, and precision. Engineers select steel, copper, titanium, or aluminum MIM materials to ensure proper molding, sintering, and machining for consistent results.

The specific alloy composition and powder characteristics influence important factors such as densification, shrinkage, mechanical performance, and corrosion resistance. They also affect production efficiency, including yield, defect rates, and overall cost. If you overlook these considerations, you risk parts that warp, fail to meet tolerances, or require expensive rework. Engineers prioritize metal selection as a foundational step in the MIM process and design components to align with the capabilities and limitations of the chosen material. In short, picking the right metal upfront makes the whole metal injection molding process smoother, more reliable, and more cost-effective.

What Should Be Considered When Choosing MIM Materials?

When choosing materials for metal injection molding (MIM), there are several key factors you need to consider to make sure your parts come out right. First, mechanical properties like tensile strength, hardness, toughness, and flexibility must match the application. Engineers tailor different alloys and powder compositions to achieve the required strength and wear resistance.

Corrosion resistance is another critical factor. Materials like stainless steel, nickel alloys, or titanium provide long-term durability, especially in harsh environments or for medical and aerospace applications. Similarly, wear resistance is important for high-abrasion parts, such as automotive components, where harder MIM steels or tungsten alloys help extend part life.

Engineers consider magnetic or biocompatible properties, using ferromagnetic alloys for motors and titanium or cobalt-chromium for medical devices. Production depends on sintering, molding, and machinability, with powder shape, size, and reactivity affecting flow, moldability, and dimensional accuracy. Softer alloys ease machining; reactive powders need careful debinding.

Finally, cost and regulatory compliance play a big role. Using lower-cost alloys like stainless steel MIM can help control expenses in high-volume production, while medical or aviation alloys may require strict certifications. Choosing the right material upfront balances performance, manufacturability, and cost, ensuring consistent, high-quality MIM parts with minimal post-processing issues.

Which Stainless Steels Are Best for MIM?

Stainless steel is one of the most popular choices for metal injection molding because it offers a great balance of strength, corrosion resistance, and machinability. Engineers use it to produce parts that require durability, precision, and, in some cases, biocompatibility.

Stainless Steel Grade	Key Properties	Typical Applications
304	Excellent corrosion resistance; high strength and hardness after heat treatment; biocompatible grades available	Medical instruments, dental tools, general-purpose corrosion-resistant parts
316 / 316L	Superior corrosion resistance; resistant to marine and chemical environments	Marine hardware, pharmaceutical equipment, food processing
17-4 PH	Can be precipitation hardened for high strength and hardness	Functional and structural components, automotive parts
420	~13% chromium, high carbon; high wear resistance; excellent edge retention; easy to machine unless hardened above 30 HRC	Corrosion-resistant precision components, cutting tools, small complex parts
440C / 430	High hardness and wear resistance	High-strength tools, industrial components requiring durability

Stainless steel MIM offers strength, corrosion resistance, and precision, making it a reliable, cost-effective choice for diverse applications.

Which Low-Alloy Steels Work for MIM?

Low-alloy steels, containing small amounts of chromium, nickel, and molybdenum, offer a strong, cost-effective option for metal injection molding (MIM) with improved toughness, wear resistance, and heat-treatability.They’re also more ductile than stainless steel, easy to machine, and generally ferromagnetic, with typical densities around 7.7–7.8 g/cc. Plus, they’re more affordable than stainless or exotic alloys.

Common low-alloy steel grades used in MIM include 4140, 4340, 4605, 2700, 2200, 52100, 8620, 9310, 430L, and H13. Heat-treated steels gain high tensile and yield strength with good ductility, making them ideal for high-strength structural components.

In practice, low-alloy steels are widely used for:

Automotive parts like gears, cams, and shafts
Industrial machinery components requiring wear resistance
Consumer products such as hand tools, sporting goods, and electronics
Military and firearm components
Any part that benefits from post-sintering heat treatment or serves as a cost-effective alternative to machined steel

Choosing the right low-alloy steel ensures proper sintering, dimensional stability, and efficient post-processing. The result is durable, high-precision MIM parts with complex geometries, produced more efficiently than with traditional machining or casting.

Which Tool Steels Are Common in Metal Injection Molding?

In metal injection molding (MIM), selecting the right tool steel is essential for high-quality parts and durable molds. Steels like H-13, S-7, P-20, M2, and D2 provide hardness, wear resistance, and thermal stability for MIM molds and dies.

Tool Steel	Hardness / Heat Treatment	Key Properties	Typical Applications	Notes / Limitations
H-13	Heat-treatable; high-volume suitable	Excellent strength, thermal fatigue resistance, good machinability, versatile for hot & cold work	High-volume molds, abrasive plastics, hot work tooling	Surfaces may corrode over time due to moisture or chemically enhanced plastics
S-7	Pre-hardened; tight tolerances	Excellent wear and shock resistance, stable under heat, resists softening	Slides, lifters, molds requiring impact resistance	Ideal for high-volume, high-precision molding
P-20	Pre-hardened 28–30 HRC	General-purpose, good dimensional stability, can be used directly	Prototypes, holder blocks, low-volume molds	Not ideal for abrasive plastics or very high-volume runs unless coated/hardened
M2	Can be heat-treated >HRC60	Very hard, excellent wear resistance, maintains cutting edges	Cutting tools, dies, high-wear components	Brittle; sintering to full density is challenging
D2	Can be heat-treated >HRC60	Extremely hard, abrasion-resistant	High-wear tooling, dies, punches	Brittle; requires careful handling
General Tool Steel Properties	–	High hardness, wear resistance, good hot strength, density ~7.7–8.1 g/cc	–	Lower corrosion resistance than stainless steel

In short, tool steels allow MIM to produce complex, high-performance components efficiently, especially in small to medium volumes. Choosing H-13, S-7, or P-20 steel ensures durable molds and high-performance parts in Metal Injection Molding (MIM) applications.

Can Titanium Be Used in MIM?

Yes, you can do titanium injection molding using specialized metal injection molding (MIM) machines. Titanium alloys offer high strength-to-weight, corrosion resistance, and biocompatibility, ideal for aerospace, medical implants, and high-performance applications.

Ti-6Al-4V, lightweight, strong, heat-resistant, and bioinert, enables complex shapes, making it a versatile Metal Injection Molding (MIM) material.

Titanium Alloy / Grade	Key Properties	Advantages	Typical Applications	Notes / Limitations
Ti-6Al-4V (Grade 5)	High strength-to-weight ratio, good high-temperature properties, biocompatible, corrosion and oxidation resistant, low density (~4.5 g/cc)	Lightweight yet strong, bioinert, suitable for complex geometries, excellent corrosion resistance	Aerospace parts, medical implants and instruments, valves, nozzles, fluid system components, high-performance sports equipment, luxury items (jewelry, watches, eyeglasses)	High cost compared to steel/aluminum, reactive powder requiring controlled processing, difficult to fully sinter to maximum density
General Titanium MIM Properties	Lightweight, strong, corrosion-resistant, biocompatible	Can produce intricate shapes and complex parts, suitable for demanding applications	Aerospace, medical, high-performance sporting goods, luxury products	Costly, sintering challenges, requires specialized MIM equipment

Overall, titanium MIM makes it possible to produce complex, lightweight, and highly durable parts. Despite higher cost and sintering challenges, titanium MIM excels in applications requiring strength, low weight, and excellent corrosion resistance.

Is Tungsten Suitable for MIM Applications?

Tungsten MIM is all about extreme density, wear resistance, and handling high temperatures.

Tungsten’s high density, hardness, and melting point make it ideal for aerospace, defense, electronics, tooling, and medical applications.

Category	Details
Material / Alloy	Tungsten and its alloys (W-Ni-Fe, W-Ni-Cu)
Key Properties	Extremely high density (~17–18 g/cc), remarkable hardness, highest melting point of any metal (3400°C), high strength at elevated temperatures, excellent corrosion and wear resistance, can be alloyed to improve sintering and machinability
Advantages	Ideal for high-density, wear-resistant, and heat-tolerant parts; allows complex shapes and intricate components that are difficult or expensive to machine traditionally
Typical Applications	Aerospace radiation shielding, ballast/counterweights, vibration-damping components, high-wear tooling (punches, dies, cutting tools), high-temperature furnace parts, heavy alloy substitutes
Notes / Limitations	Challenging to fully sinter and achieve total density; requires specialized MIM processing; high cost

In short, tungsten MIM is perfect when you need high-density, wear-resistant, and heat-tolerant parts. Full sintering density is challenging, but MIM produces complex tungsten components that are strong, precise, and highly reliable.

What Are Aluminum Options for MIM?

Aluminum MIM—also called Aluminum Alloy Injection Molding (AIM)—lets you produce lightweight, corrosion-resistant, and high-precision metal parts, including very complex shapes. It’s based on metal injection molding (MIM), a branch of powder injection molding(PIM), and has quickly become one of the fastest-growing methods for near-net-shape aluminum parts worldwide.

Category	Details
Material / Alloy	Aluminum alloys (AIM / Aluminum MIM)
Key Properties	Lightweight with low density, good strength-to-weight ratio, excellent corrosion resistance, high precision and uniform density after sintering, capable of extremely complex geometries, relatively low cost
Processing Considerations	Aluminum powder has a thick oxide layer; requires careful furnace atmosphere control; two-step sintering process (oxygen-rich atmosphere to remove carbon, then nitrogen with magnesium to break oxide layer); binder removal overlaps with sintering
Advantages	Lightweight yet strong, corrosion-resistant, capable of producing complex 3D shapes, high precision, minimal post-processing, cost-effective compared to other MIM metals
Typical Applications	Complex 3D components, large-volume high-precision parts, lightweight structural components
Industries	Aerospace & aviation, automotive parts, navigation & marine engineering, machinery and precision instruments

Aluminum MIM offers lightweight, precision, and design flexibility, ideal for applications requiring weight reduction, high efficiency, and consistent quality. With the right processing, it’s possible to make high-density, defect-free aluminum components at a relatively low cost.

Which Magnetic Alloys Work in MIM?

Magnetic alloys like iron, nickel, and cobalt can be MIM-processed to create precise, intricate components, including μMIM applications.By adjusting the alloying elements, manufacturers can tailor magnetic properties like permeability, saturation, and core losses to suit specific applications.

Category	Details
Material / Alloy	Magnetic alloys (Fe-Ni, Fe-Si, Fe-Co, soft ferrites, specialty steels)
Key Properties	Ferromagnetic; high permeability and saturation magnetization; magnetic performance tailored via alloying; controlled microstructure and porosity required; often requires post-sintering heat treatment; densities ~7.5–8.5 g/cc
Advantages	Enables precise fabrication of intricate magnetic components; customizable magnetic properties; suitable for micro MIM (μMIM) applications; low energy-loss cores achievable
Typical Applications	Transformers, inductors, electric motors; solenoids, actuators, valves, switches; sensors; MEMS devices; magnetic tooling and holding fixtures; motorsports magnet components
Processing Notes / Limitations	Alloy chemistry, microstructure, and porosity must be carefully controlled; precision sintering required to achieve desired magnetic properties

In short, MIM allows precise fabrication of complex magnetic parts that are difficult or impossible to produce with traditional methods. Controlling alloy chemistry, microstructure, and porosity is crucial to achieving the desired magnetic performance while maintaining high precision.

Can Copper Be Used in MIM?

Copper MIM produces precision components—connectors, switches, heat sinks, and friction parts—offering excellent thermal and electrical conductivity.

Category	Details
Material / Alloy	Copper, Bronze (Cu-Sn), Brass (Cu-Zn), Tungsten-Copper
Key Properties	Excellent electrical and thermal conductivity; relatively soft and ductile; low melting point compared to steel/titanium; corrosion/tarnish susceptibility varies by alloy; alloying improves strength and wear resistance; densities ~8.5–9 g/cc
Advantages	High conductivity for electrical and thermal applications; easy to shape and mold; cost-effective compared to machined copper parts; properties can be tailored via alloying
Typical Applications	Electrical contacts, connectors, and switches; heat exchangers and heat sinks; bearings, bushings, friction disks; low-force transmission components like gears or cams; decorative fittings and jewelry
Processing Notes / Limitations	Requires proper MIM processing to maintain conductivity and dimensional stability; corrosion/tarnish protection may be needed depending on alloy

In short, copper MIM combines excellent conductivity, flexibility, and cost-effectiveness, making it ideal for electrical, thermal, and moderate load-bearing applications. With the right alloying, you can tailor properties to meet the specific performance needs of your parts.

How to Choose the Right Material for Strength, Corrosion Resistance, and Precision in MIM?

Metal Injection Molding (MIM) starts with picking the right feedstock. The key is balancing strength, corrosion resistance, machinability, and cost to match your part’s requirements.

Common MIM materials include stainless steel, cobalt, nickel alloys, titanium, aluminum, and copper. Each has its advantages, so consider:

Compatibility with your MIM machine
Sintering behaviorand post-processing
Part design and production volume

Custom feedstocks can provide maximum strength and consistency. Consulting a manufacturer or materials expert helps ensure you choose the best metal for your application, including specialty alloys if needed.

Mechanical Properties

TYPE		ALLOY	DENSITY (G/CM³)	UTS 10³ PSI	YIELD STRENGTH (0.2%) 10³ PSI	ELONGATION (IN 1 INCH)	HARDNESS MACRO (APPARENT) ROCKWELL
Stainless	Austenitic	304	7.58	74	29	40	92 HRB
Stainless	Austenitic	316L (MIM 316L)	7.60	75	25	50	67 HRB
Stainless	Ferritic	430	7.75	60	35	25	65 HRB
Stainless	Martensitic	420	7.40	200	174	<1.0	67 HRB
Stainless	Martensitic	440C	7.65	286	276	14	97 HRB
Stainless	Precipitation Hardened	17-4PH (MIM 17-4)	7.50	130	106	6	27 HRC
Stainless	Duplex	316L Duplex	7.60	84	38	40	77 HRB
Soft Magnetic	ASTM A801 Type 1	49FeCo2V	7.71	195	185	1	36 HRC
Soft Magnetic	ASTM A801 Type 2	Fe27Co	7.55	80	41	12	80 HR 15T
Soft Magnetic	ASTM A753 Type 2	49NiFe	7.83	73	12	38	80 HR 15T
Soft Magnetic	ASTM A753 Type 4	80NiFeMo	8.39	84	32	40	81 HR 15T
Soft Magnetic	MIM 430L	430L	7.55	60	35	25	65 HRB
Controlled Thermal Expansion (CTE)	ASTM F15 (Kovar)	FeNiCo	7.80	75	51	42	60 HRB
Controlled Thermal Expansion (CTE)	ASTM F1684 (Invar)	Alloy 36 (36NiFe)	8.00	62	35	40	65 HRB
Controlled Thermal Expansion (CTE)	ASTM F30	Alloy 42 (42NiFe)	7.79	71	36	42	70 HRB
Low Alloy Steel	MIM 2200	2% NiFe	7.65	42	18	40	45 HRB
Low Alloy Steel	MIM 2700	7% NiFe	7.60	60	37	26	69 HRB
Low Alloy Steel	MIM 4605	2%Ni 0.35Mo 0.5C	7.5	64	30	15	62 HRB
Low Alloy Steel	Carbon Steel	4140	7.85	84	57	15	18 HRB
Low Alloy Steel	Tool Steel	S7	7.40	268	212	2	50 HRC
Implantable Alloys	ASTM F75	CoCr	8.09	95	65	8	35 HRC
Non Ferrous	Cooper	Cu	8.66	–	–	–	–
Non Ferrous	Bronze	Cu Sn	8.18	–	–	–	–

Chemical Composition (%)

Type	Alloy	Key Elements	แอปพลิเคชัน
Stainless Austenitic	304	C≤0.03, Ni12–13, Cr17–18	Corrosion-resistant parts
Stainless Austenitic	316L	C≤0.03, Ni8, Cr20, Mo≤2	MIM corrosion-resistant
Stainless Martensitic	420	C0.15–0.4, Ni3–5, Cr15.5–17.5	Hard, wear-resistant
Stainless Martensitic	440C	C0.95–1.2, Cr16–18, Mo0.75	High-hardness parts
Stainless PH	17-4PH	C≤0.07, Ni3–5, Cr15.5–17.5, Cu3–5	Strong, PH
Stainless Duplex	316L Duplex	C≤0.03, Ni10–14, Cr16–18, Mo2–3	High strength
Soft Magnetic	A801 T1	FeCoV49, C≤0.025	Magnetic parts
Soft Magnetic	A801 T2	Fe27Co, C≤0.025	Magnetic parts
Soft Magnetic	A753 T1	NiFe49, C≤0.05	Magnetic parts
Soft Magnetic	A753 T4	NiFeMo80, C≤0.05	Magnetic parts
Soft Magnetic	430L	C≤0.05, Cr16–18	Magnetic MIM parts
CTE	Kovar	FeNiCo, C≤0.04, Ni29	Low-expansion parts
CTE	Invar36	36NiFe, C≤0.05	Low-expansion parts
Low Alloy Steel	MIM2200	Ni2%, C≤0.01	Structural parts
Low Alloy Steel	MIM2700	Ni7%, C≤0.01	Structural parts
Low Alloy Steel	MIM4605	Ni2%, Mo0.35, C0.5	Structural parts
Low Alloy Steel	4140	C0.041, Cr1.01, Mo0.23	General steel
Low Alloy Steel	S7	C0.45–0.7, Cr2.5–3.5, Mo1–1.8	Tooling/molds
Implantable	ASTM F75	CoCr, Cr27, Mo5	Medical implants
Non-Ferrous	Cu	Cu100	Conductive parts
Non-Ferrous	Bronze	Cu90, Sn9–10	Bearings/bushings
Non-Ferrous	Ti-6Al-4V	Ti6-4, Al5.5–6.5, V3.5–4.5	Lightweight/biocompatible
Superalloys PH	A-286	Ni24–27, Cr13.5–16, Ti1.9–2.35	High-temp parts
Superalloys PH	718	Ni50–55, Cr17–21, Nb4.7–5.5	High-temp parts
Superalloys PH	713LC	Ni11.5–12.5, Cr4–5, Al5.5–6.5	High-temp parts
Superalloys PH	Alloy90	Ni18–21, Cr1, Ti2–3	High-temp parts
Superalloys SS	L-605	Ni9–11, Cr19–21, W14–16	Solution-strengthened
Superalloys SS	188	Ni20–24, Cr20–24, W13–16	Solution-strengthened
Superalloys SS	MAR-M-509	Ni9–11, Cr23–24.25, W6.5–7.5, Ta3–4	Solution-strengthened

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MIM Materials FAQ’S

Which tool steel is right for your plastic injection mold?

Selecting the right tool steel for injection molding depends on your part’s complexity, production volume, and material type. Common choices include P-20, H-13, and S-7 steels. P-20 is suitable for standard molds with moderate wear, H-13 works for high-temperature molding, and S-7 offers superior shock resistance for complex or high-stress parts. Choosing the proper steel ensures durability and precision in injection mold tooling.

What are the differences between MIM steel and standard steel for molding?

MIM steel is specifically designed for the metal injection molding process, offering high sinterability, dimensional stability, and fine microstructure. Standard steel may not perform well in powder injection molding or micro metal injection molding because it can cause defects, warping, or poor surface finish. Selecting MIM-compatible steels ensures high-quality, precise, and durable parts.

Can injection molded metals be used for high-precision components?

Yes, metal injection molding enables the production of high-precision MIM parts, including microcomponents. Materials like stainless steel, titanium, and copper are often used for applications in medical devices, electronics, and aerospace. Proper MIM technology and metal injection molding machines ensure consistent dimensions, smooth surfaces, and reliable mechanical properties.

Why Choose welleshaft For MIM Manufacturing

A professional metal injection molding company, เวลเลชาฟท์, provides expertise in MIM technology, process optimization, and quality assurance. Welleshaft can handle complex metal injection molding services, from powder injection molding to finished MIM parts, ensuring dimensional accuracy, material performance, and production efficiency. Partnering with an experienced supplier like Welleshaft reduces defects, improves yield, and guarantees reliable MIM parts for industrial or commercial applications.

This blog was provided by the เวลเลชาฟท์ Engineering Team, led by Mr. Xu, with 20+ years of experience in metal injection molding (MIM) and precision manufacturing. Welleshaft specializes in MIM process, custom alloys, and high-quality metal parts for industrial and commercial applications.