Stainless Steel 440C seamless tubes and hollows (UNS S44004, EN 1.4125) are made for applications where high hardness and wear resistance are the main requirements. With 0.95% to 1.20% carbon, 440C has the highest carbon content in the 440 family and can reach around 58 to 60 HRC after hardening. That makes it a strong choice for components that need to retain a hard, wear resistant surface in service. Amardeep Steel supplies SS 440C seamless tubes and hollows with EN 10204 3.1 mill test certificates, heat treatment records and full heat traceability. Compare our SS 440A seamless pipes and tubes and SS 440B seamless pipes and tubes, or see our SS 440 tubes.
What Are Stainless Steel 440C Seamless Pipes & Tubes?
Grade 440C is the hardest and most wear resistant of the common stainless steels. Its corrosion resistance is moderate, best after tempering below about 400 degrees Celsius and on clean, scale free surfaces. It is used where hardness and wear life matter most.
How 440C Seamless Tube Is Produced
High carbon 440 grades are made mainly as bar, wire and billet, and no ASTM tube specification lists them. Seamless 440C tube is therefore produced to drawing, usually by piercing or boring hollow bar, and supplied annealed for machining. The final hardness comes from the buyer's own hardening and tempering after machining, or from heat treatment we arrange to the drawing.
SS 440C Seamless Tube Specifications
Parameter | Details |
|---|---|
Grade | Stainless Steel 440C (AISI 440C) |
UNS | S44004 |
Chemistry Basis | ASTM A276 / A580 limits for the grade; tube made to drawing or purchase specification |
Type | Seamless, hot finished or cold drawn, and machined hollows |
Size Range | To drawing or purchase specification |
Length | Random, fixed and cut lengths |
Supply Condition | Annealed for machining; hardened and tempered on request |
Test Certificate | EN 10204 3.1, with 3.2 available on request |
SS 440C Chemical Composition
Element | Content (%) |
|---|---|
Carbon (C) | 0.95 to 1.20 |
Chromium (Cr) | 16.00 to 18.00 |
Molybdenum (Mo) | 0.75 max |
Manganese (Mn) | 1.00 max |
Silicon (Si) | 1.00 max |
Phosphorus (P) | 0.040 max |
Sulfur (S) | 0.030 max |
SS 440C Mechanical Properties
Property | Value |
|---|---|
Typical hardness, annealed | 97 HRB |
Typical hardness, hardened and tempered at 315 degrees Celsius | 57 HRC |
Commonly specified hardness after heat treatment | 58 HRC min |
Typical properties, hardened and tempered at 315 degrees Celsius | Tensile about 1965 MPa, yield about 1896 MPa, elongation about 2% |
These are typical values from published data, not specification minimums. The hardness you receive depends on section size and on the hardening and tempering cycle, which is agreed with your order.
SS 440C Equivalent Grades
Standard | Designation |
|---|---|
UNS | S44004 |
AISI | 440C |
EN / Werkstoff No. | 1.4125 (X105CrMo17) |
JIS | SUS440C |
GB | 11Cr17 |
Equivalent grades are close matches, not direct substitutes. Check the drawing before switching standards.
440A vs 440B vs 440C
Property | 440A | 440B | 440C |
|---|---|---|---|
Carbon | 0.60 to 0.75% | 0.75 to 0.95% | 0.95 to 1.20% |
Chromium | 16 to 18% | 16 to 18% | 16 to 18% |
Typical hardness, tempered at 315 degrees Celsius | 51 HRC | 55 HRC | 57 HRC |
Corrosion resistance | Best of the three | Middle | Lowest of the three |
Toughness | Highest | Middle | Lowest |
Carbon rises from 440A to 440C, which raises hardness and wear resistance but lowers corrosion resistance and toughness. See our SS 440 tubes for the full family and our SS 420C bars for a lower carbon martensitic option.
Applications of SS 440C Seamless Pipes and Tubes
- Bearing races and rolling elements
- Needle valves and ball check valve parts
- Nozzles and wear sleeves
- High wear blade and tool parts
Testing and Documentation
Every order of SS 440C seamless tube goes through the checks below at our testing facility or approved third party labs.
- Chemical analysis and PMI
- Hardness test on each heat treatment lot
- Ultrasonic or eddy current testing on request
- Visual and dimensional inspection
Mill test certificates are issued to EN 10204 3.1, with 3.2 available on request. You can view our approvals on the certificates page.
Packing and Marking
Each length is marked with grade, size, heat number and heat treatment condition. Bores are oiled and capped. Tubes are packed in bundles or wooden boxes for export. Read more about our packing and despatch process.
Request a Quote for Stainless Steel 440C Seamless Pipes & Tubes
Send us the OD, ID or wall thickness, heat treatment condition, length and quantity, and our team will reply with price and delivery. Use the enquiry form or reach us through the contact page.
Frequently Asked Questions
What is Stainless Steel 440C?
Stainless Steel 440C (UNS S44004, EN 1.4125) is a high carbon martensitic stainless steel with 0.95 to 1.20% carbon and 16 to 18% chromium. It reaches about 58 to 60 HRC after heat treatment.
What is 440C used for?
440C is used for bearings, needle and ball check valve parts, nozzles and other parts that need very high hardness and wear resistance.
What is the EN equivalent of 440C?
The EN equivalent is 1.4125 (X105CrMo17). The JIS equivalent is SUS440C.
Is there an ASTM tube specification for 440C?
No. 440C is covered as bar, wire and billet. Seamless 440C tube and hollows are produced to drawing.
