What is 1.4112 Stainless Steel?

1.4112 stainless steel, commonly known as 440B or UNS S44003, is a higher carbon martensitic stainless steel within the 440 series. It offers a balance of high hardness, wear resistance, and moderate corrosion resistance, positioned between 440A and 440C. This grade is often used for cutlery, bearings, and valve components where a combination of hardness and corrosion resistance is needed.

 

This mid-range hardness martensitic grade is recognized under several standards.

Standard	Equivalent Grade
EN (Europe)	1.4112
ASTM/AISI (USA)	440B, UNS S44003
JIS (Japan)	SUS440B
KS (Korea)	STS440B

Its carbon content is higher than 440A but lower than 440C, balancing hardness and toughness.

Element	C	Si	Mn	P	S	Cr	Mo
Content (%)	0.75 - 0.95	≤ 1.0	≤ 1.0	≤ 0.04	≤ 0.03	16.0 - 18.0	0.4 - 0.8

Mechanical properties vary significantly with heat treatment.

Condition	Yield Strength (Rp0.2)	Tensile Strength (Rm)	Elongation (A)	Hardness (HRC)
Annealed	~ 450 MPa	~ 740 MPa	~ 14%	~ 25 HRC
Hardened & Tempered	≥ 700 MPa	≥ 850 MPa	≥ 10%	55 - 58 HRC

 

Key Characteristics and Applications of 1.4112 / 440B

High Hardness and Wear Resistance: Can be heat treated to achieve high hardness (up to ~58 HRC), providing good wear resistance and edge retention.

Moderate Corrosion Resistance: Offers better corrosion resistance than many tool steels but less than austenitic grades like 304. Suitable for mild corrosive environments.

Magnetic and Hardenable: Strongly magnetic and responds well to heat treatment for hardening.

 

Primary Applications:

Cutlery: High-quality knives, blades, and surgical instruments requiring a balance of hardness and corrosion resistance.

Bearings and Valve Parts: Ball bearings, valve seats, and pump components where wear resistance is critical.

Industrial Tools: Gauges, molds, and machine parts requiring hardness and dimensional stability.

Dental and Surgical Tools: Instruments that require sharp edges and sterilization compatibility.

 

What distinguishes 440B (1.4112) from 440A and 440C?
The primary difference is carbon content: 440A has 0.60-0.75% C, 440B has 0.75-0.95% C, and 440C has 0.95-1.20% C. This results in 440B offering a middle ground-higher hardness and wear resistance than 440A, but with better toughness and slightly easier machining than 440C. 440B is often chosen when a balance between hardness, toughness, and corrosion resistance is needed without the extreme hardness (and brittleness) of 440C.

 

What is the recommended heat treatment for 440B stainless steel?
Typical heat treatment involves austenitizing at 1010-1065°C, followed by oil quenching to achieve maximum hardness. This is followed by tempering at temperatures between 150-370°C, depending on the desired balance of hardness and toughness. Lower tempering temperatures yield higher hardness; higher temperatures increase toughness with some reduction in hardness. Double tempering is often used to ensure stress relief and stability.

 

Looking for a Reliable Supplier of 1.4112 / 440B Stainless Steel?
GNEE Steel supplies high-quality 440B (1.4112) stainless steel in bar, wire, and strip forms, available in annealed or heat-treated conditions to meet specific hardness and wear resistance requirements. We provide material certification and processing support. If you have any requirements, please feel free to contact us.