Introduction
440B stainless steel is a high-carbon martensitic stainless steel designed to deliver an optimal balance of hardness, wear resistance, and moderate corrosion resistance. Containing approximately 17% chromium and a carbon content ranging from 0.75% to 0.95%, this grade achieves significantly higher hardness than its 440A counterpart while retaining better toughness than 440C.
The microstructure features a martensitic matrix with chromium carbides, which provides exceptional wear and abrasion resistance. It is well-suited for applications requiring both edge retention and structural integrity under stress. At FUSHUN METAL, we precisely control the carbon and chromium balance to ensure our 440B steel offers superior hardenability and reliable performance in demanding environments. Tell us your requirements, and let us provide the exact material solution you need.
Equivalent Grades
| Standard | Grade |
|---|---|
| ASTM | 440B |
| UNS | S44003 |
| EN | X90CrMoV18 |
| DIN | 1.4112 |
| JIS | SUS440B |
Applications
Suitable for applications requiring an excellent combination of wear resistance and moderate corrosion resistance, 440B is commonly used for:
- High-end cutlery and kitchen knives
- Surgical scalpels and dental instruments
- Rolling element bearings and bearing components
- Valve seats and needle valves
- Industrial blades and shear knives
- Razor blades and cutting tools
- Measuring instruments and gauges
- Marine hardware requiring high hardness
Specifications & Standards
440B stainless steel is officially recognized and specified in the following international standards:
- ASTM A276 – Standard Specification for Stainless Steel Bars and Shapes (Round, Flat, Square, Hexagons)
- ASTM A484 – Standard Specification for Stainless Steel Bars, Billets, and Forgings (General Requirements)
- EN 10088-3 – Stainless Steels – Semi-finished products, bars, rods, and sections (Round, Flat)
Available Sizes & Delivery
FUSHUN METAL possesses robust manufacturing capabilities to supply 440B stainless steel across a wide dimensional spectrum. Equipped with a 6000-ton hydraulic press and a GFM radial forging machine, we ensure exceptional structural integrity and uniform grain flow in our products.
- Hot Rolled Round Bars: Ø 10mm – Ø 150mm
- Forged Round Bars: Ø 150mm – Ø 800mm
- Hot Rolled Flat Bars: Thickness 10mm – 100mm / Width 50mm – 400mm
- Forged Flat Bars: Thickness 100mm – 500mm / Width 200mm – 800mm
- Wire Rod: Ø 5mm – Ø 16mm
Delivery & MOQ
- Ready Stock
- Common sizes are available in inventory with single-piece minimum order quantity, delivering within ~7 days.
- Custom Forgings/Rolled Products
- MOQ usually starts at 3 tons, with a lead time of ~30 days.
- Small Batches
- We operate small induction furnaces allowing flexible melts starting from 3-5 tons for special requirements.
- Large Volumes
- Our 30-60 ton EAF capacity ensures fast delivery for bulk orders. Contact us for a free quote on your specific sizes.
Chemical Composition
| Grade | C | Si | Mn | P | S | Cr | Mo | V |
|---|---|---|---|---|---|---|---|---|
| 440B (ASTM) | 0.75 - 0.95 | 1.0 max | 1.0 max | 0.040 max | 0.030 max | 16.0 - 18.0 | 0.75 max | - |
| 1.4112 (EN) | 0.85 - 0.95 | 1.0 max | 1.0 max | 0.040 max | 0.030 max | 17.0 - 19.0 | 0.90 - 1.30 | 0.07 - 0.12 |
Note: The EN 1.4112 grade features a slightly higher chromium range, mandatory molybdenum content, and a vanadium addition compared to the ASTM 440B specification, offering marginally better edge retention and pitting resistance.
Melting & Processing
For 440B stainless steel, FUSHUN METAL offers flexible melting routes tailored to your application. The standard process is EAF + AOD + LF + VD, ensuring excellent purity for general engineering. For critical applications requiring superior micro-cleanliness and reduced segregation, we provide ESR (Electroslag Remelting) or PESR. For the highest demanding aerospace or medical applications, VIM + VAR (Vacuum Induction Melting + Vacuum Arc Remelting) is available. Consult our metallurgists to select the most cost-effective and technically suitable melting process.
Mechanical Properties
| Condition | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness |
|---|---|---|---|---|
| Annealed | ≥ 690 | ≥ 275 | ≥ 14 | 265 HB max |
| Hardened & Tempered | ≥ 1790 | ≥ 1650 | ≥ 3 | 56 - 58 HRC |
Heat Treatment
| Treatment | Temperature Range | Holding Time | Cooling Method |
|---|---|---|---|
| Annealing | 843 - 871°C | 1 - 2 hours per inch | Furnace cool slowly |
| Hardening (Austenitizing) | Pre-heat at 760°C, then 1010°C | 30 minutes | Oil or Air quench |
| Tempering (Max Hardness) | 148°C | 2 hours | Air cool |
Note: Air cooling after forging or hardening of 440B may cause cracking; immediate tempering or furnace cooling is highly recommended.
Surface Finish & Machining
FUSHUN METAL provides versatile surface finishes for 440B products. Bars can be supplied in the black (as-forged) condition. For precision needs, we offer turning (Ra 3.2-6.3μm), grinding (Ra 0.8-1.6μm), and milling (Ra 1.6-3.2μm). CNC machining is available for near-net-shape components. Turned and ground round bars achieve tight dimensional tolerances (h9 to h11), while milled flat bars maintain precise thickness and width.
Machining is best performed in the annealed condition using carbide or ceramic tooling with chip breakers to manage tough, stringy chips.
Quality Assurance & Inspection
Quality at FUSHUN METAL is controlled through rigorous pre-production, in-process, and post-production inspections. Ultrasonic Testing (UT) is performed according to SEP 1921 or ASTM E2375 to ensure internal soundness. We conduct comprehensive chemical analysis, mechanical testing, dimensional checks, and metallographic examination.
EN 10204 3.1 certificates are standard, and 3.2 certification is available upon request. Third-party inspections by SGS or TÜV can be arranged. Our quality management system is certified to ISO 9001 and AS9100, guaranteeing traceability and consistency for every heat.
Packing & Shipping
We ensure 440B stainless steel arrives in pristine condition. Black surface products are securely bundled with steel wire strapping, designed to prevent shifting and container damage during transit. For bright, turned, or ground surfaces, we apply protective wrapping materials (such as plastic film and woven bags) to safeguard surface roughness and dimensional accuracy. To combat marine environments, all products are coated with anti-rust oil, ensuring zero oxidation during ocean shipping. Custom packaging configurations are available upon request.
FAQ
- Can you cut 440B to my specific length?
- Yes, we offer precision sawing and cutting services for 440B bars. We can cut to your exact length requirements, and for hardened materials, we utilize specialized abrasive cutting methods to prevent thermal alteration of the ends.
- What is the hardness of 440B in the annealed condition?
- In the annealed condition, 440B stainless steel has a maximum hardness of 265 HB (Brinell) or approximately 26 HRC. This condition is optimal for heavy machining before final hardening.
- Is 440B suitable for welding?
- Welding is generally not recommended for 440B due to its high carbon content and air-hardening nature, which easily leads to cracking. If welding is absolutely necessary, preheating to 260°C is required, followed by a post-weld annealing treatment at 732-760°C for at least 6 hours and slow furnace cooling.
- What is the difference between 440B and 1.4112?
- While often considered equivalent, EN 1.4112 typically has a slightly higher chromium range (17-19% vs 16-18%), mandatory molybdenum content (0.90-1.30%), and a small vanadium addition (0.07-0.12%). This gives 1.4112 marginally better edge retention and corrosion resistance compared to standard ASTM 440B.
