Xi'an Dongmeng Group Co., Ltd. is one of the most reliable manufacturers and suppliers of 440c stainless steel in China, also supports customized service. With abundant experience, we warmly welcome you to wholesale cheap products in stock here and get free sample from our factory. For price consultation, contact us.
440C Stainless Steel (also known as Grade 440C, UNS S44004, AISI 440C, 440C stainless steel bar, 440C stainless steel sheet, 440C stainless steel round bar, 440C stainless steel plate) is a high-carbon martensitic stainless steel with excellent hardness, wear resistance, and high strength after heat treatment. As a professional mill-direct supplier, we provide 440C stainless steel bars, rods, plates, sheets, coils, forgings, and precision-machined components for global B2B customers in tooling, bearings, valves, aerospace, and industrial machinery.
Our factory supports:
Custom sizes & heat treatment (annealed / quenched & tempered)
Tight tolerance grinding (H9–H11)
Ultrasonic testing (UT) & PMI testing
Global export packaging
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High Quality
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Advanced Equipment
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Professional Team
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Custom Service
Products Description
440C Stainless Steel is a high-carbon martensitic stainless steel known for its ability to achieve 58–60 HRC hardness after heat treatment. It offers exceptional abrasion resistance, strength, and dimensional stability, making it widely used in cutting tools, bearings, precision instruments, pump components, and knife blades.
Standards include:
ASTM A276 / A484 – Stainless steel bars and shapes
ASTM A240 – Stainless steel plates and sheets
AMS 5630 / AMS 5880 – Aerospace specifications
UNS S44004
Keywords:
440C Stainless Steel, AISI 440C, UNS S44004, 440C stainless steel bar, 440C stainless steel plate, high-carbon stainless steel, hardened stainless steel, tooling steel stainless, martensitic stainless steel.
Chemical Composition (Typical, %)
| Element | Content (%) |
|---|---|
| Carbon (C) | 0.95 – 1.20 |
| Chromium (Cr) | 16.0 – 18.0 |
| Manganese (Mn) | ≤ 1.0 |
| Silicon (Si) | ≤ 1.0 |
| Nickel (Ni) | ≤ 0.75 |
| Molybdenum (Mo) | ≤ 0.75 |
| Phosphorus (P) | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 |
Mechanical Properties (Annealed / Hardened)
| Property | Annealed | Hardened & Tempered (Oil Quenched) |
|---|---|---|
| Hardness | ≤ 269 HB | 56–60 HRC |
| Tensile Strength | 760 MPa | 1900–2000 MPa |
| Yield Strength | 450 MPa | 1400+ MPa |
| Elongation | 18% | 10% |
| Density | 7.75 g/cm³ | - |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.75 g/cm³ |
| Thermal Conductivity | 24.2 W/m·K |
| Electrical Resistivity | 600 nΩ·m |
| Modulus of Elasticity | 200 GPa |
Available Product Forms
440C Stainless Steel Round Bar (Hot Rolled / Cold Drawn / Centerless Ground)
440C Stainless Steel Flat Bar / Square Bar
440C Stainless Steel Plate / Sheet / Strip
440C Stainless Steel Tube (limited availability)
440C Forging Billets & Blocks
Heat-treated 440C components (quenched & tempered)
440C Stainless Steel – Standard Sizes & Dimensions (Metric + Imperial)
| Product Form | Size / Diameter / Thickness | Imperial | Width | Length | Tolerance / Notes | Heat Treatment | Hardness (HRC) |
|---|---|---|---|---|---|---|---|
| Round Bar | 6–20 mm | 0.24"–0.78" | - | - | h9 / h10 | Annealed / Hardened | ≤ 269 HB / 56–60 HRC |
| Round Bar | 22–80 mm | 0.87"–3.15" | - | - | h10 / h11 | Annealed / Hardened | ≤ 269 HB / 56–60 HRC |
| Round Bar | 85–350 mm | 3.35"–13.78" | - | - | +1.0 / +3.0 mm | Annealed / Hardened | ≤ 269 HB / 56–60 HRC |
| Plate / Sheet | 0.5–3 mm | 0.02"–0.12" | 1000–2000 mm | 2000–6000 mm | ASTM A480 | Annealed / Hardened | ≤ 269 HB / 56–60 HRC |
| Plate / Sheet | 4–50 mm | 0.16"–2.0" | 1000–2500 mm | 2000–8000 mm | ±0.20–0.80 mm | Annealed / Hardened | ≤ 269 HB / 56–60 HRC |
| Strip / Coil | 0.1–1.5 mm | 0.004"–0.06" | 10–600 mm | Coiled | - | Annealed / Hardened | ≤ 269 HB / 56–60 HRC |
| Flat Bar | 5–150 mm | 0.20"–5.91" | 20–600 mm | Cut-to-length | Hot rolled / Cold drawn | Annealed / Hardened | ≤ 269 HB / 56–60 HRC |
| Square Bar | 6–100 mm | 0.24"–3.94" | - | - | ±0.05–0.3 mm | Annealed / Hardened | ≤ 269 HB / 56–60 HRC |
Inspection & Quality Assurance
To ensure stable quality for global B2B buyers:
PMI testing for material grade verification
UT ultrasonic testing (Level 2 / Level 3)
Mechanical property testing (tensile, hardness)
Dimensional inspection (CMM, micrometer, gauge blocks)
Surface roughness testing for ground bars
Third-party inspection available (SGS / BV / TUV)
Mill test certificates (EN 10204 3.1 / 3.2) provided
For quotations, samples, or technical support regarding 440C Stainless Steel bar, plate, sheet, or machining, please contact:
Our address
Room 4107, Runfeng Building, Sanqiao New Street, Weiyang District, Xi'an City, Shaanxi Province
Phone Number
+86 15769214734
440C Stainless Steel – Professional FAQ for B2B Buyers
Q1: What is the difference between 440A, 440B, and 440C stainless steel?
440A: Low carbon content, lower hardness (≤ 52 HRC), good corrosion resistance.
440B: Medium carbon content, medium hardness (54–57 HRC).
440C: High carbon (0.95–1.20%), highest hardness (56–60 HRC), excellent wear resistance.
Use 440C for applications requiring high hardness, edge retention, and abrasion resistance.
Q2: What are the typical applications of 440C stainless steel?
High-precision ball bearings and roller bearings
Knife blades, scissors, and cutting tools
Valves, pumps, and shafts in mild corrosive environments
Molds, dies, and wear-resistant fittings
Aerospace components (AMS 5630 / AMS 5880 grade)
Q3: Can 440C stainless steel resist corrosion?
440C has moderate corrosion resistance.
It performs well in dry or mildly humid environments but is not recommended for marine or highly acidic conditions.
Polishing, passivation, and coating can enhance corrosion resistance.
Q4: What heat treatment processes are used for 440C?
Annealing: 850–900°C, furnace cooling for machinability.
Hardening: 1010–1065°C, oil or air quench.
Tempering: 150–370°C depending on desired hardness.
Cryogenic treatment: Optional for enhanced dimensional stability.
After proper heat treatment, hardness can reach 56–60 HRC.
Q5: What mechanical properties can I expect from 440C?
| Property | Annealed | Hardened & Tempered |
|---|---|---|
| Tensile Strength | 760 MPa | 1900–2000 MPa |
| Yield Strength | 450 MPa | 1400+ MPa |
| Elongation | 18% | 10% |
| Hardness | ≤ 269 HB | 56–60 HRC |
Q6: Do you provide precision machining or ground bars?
Yes, our factory can supply:
Centerless ground bars (tight tolerance H9–H11)
CNC machining for complex components
Polishing and surface finishing
Heat-treated components ready for industrial use
Q7: Can you provide material certification?
Yes, we provide:
Mill Test Certificates (MTC) EN 10204 3.1 / 3.2
Chemical composition verification
Mechanical property testing reports
Third-party inspection reports (SGS, BV, TUV) available on request
Q8: What are the standard forms and sizes supplied?
Round bar, flat bar, square bar, plate, sheet, strip, coil
Diameter / thickness: 0.1 mm – 350 mm
Width: 10–2500 mm
Heat-treated and non-heat-treated options available
Q9: What is the typical lead time?
7–25 days depending on:
Product form and dimensions
Quantity
Heat treatment or precision grinding requirements
Expedited orders can be arranged for urgent projects.
Q10: How do you ensure quality consistency?
Chemical composition verification (PMI / spectrometer)
Mechanical testing (tensile, hardness, elongation)
Non-destructive testing (ultrasonic, dye penetrant)
Dimensional inspection (CMM, gauge blocks, micrometer)
Surface finish inspection for ground bars
Third-party inspection available before shipment
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