Project Description
12Cr12 / 403 Stainless Steel Seamless Tube
12Cr12, also designated as 1Cr12, S40300 (UNS), AISI 403, and SUS403 (JIS), is a martensitic stainless steel containing nominally 12% chromium. This grade delivers an effective combination of corrosion resistance, elevated-temperature strength, and good damping capacity. Supplied as seamless tubes, 12Cr12 is widely specified for turbine blades, steam valve components, compressor parts, and high-temperature bolting in power generation and petrochemical industries.
At Fushun Steel Tube, we manufacture 12Cr12 seamless tubes through hot-rolling or cold-drawing processes, backed by in-house steelmaking with EAF + LF + VD refining. For critical applications, optional ESR or VIM+VAR remelting routes are available to achieve superior cleanliness and microstructure uniformity. We deliver finished tubes with contact us for a free quote competitive pricing and full material certification.
Applications
12Cr12 seamless tubes serve demanding environments where moderate corrosion resistance and reliable mechanical strength at elevated temperatures are required:
- Steam turbine blades, buckets, and nozzle boxes
- High-temperature valve stems, seats, and bushings
- Compressor impellers and rotor components
- Heat exchanger tubes in moderate corrosive media
- Boiler superheater and reheater tubes up to 650°C
- Petrochemical process piping and furnace components
- Hydraulic cylinder tubes requiring wear resistance after hardening
Product Image
Specifications & Standards
12Cr12 and its international equivalents are covered under the following standards. Fushun Steel Tube manufactures to all listed specifications, with an emphasis on seamless tube and pipe standards:
Chinese Standards (GB)
- GB/T 14975 — Seamless stainless steel tubes for structural use
- GB/T 14976 — Seamless stainless steel tubes for fluid transport
- GB/T 1220 — Stainless steel bars (grade reference)
- GB/T 8732 — Steel blades for steam turbines (grade 1Cr12/12Cr12)
American Standards (ASTM/ASME/UNS)
- ASTM A511 — Seamless stainless steel mechanical tubing
- ASTM A268/A268M — Seamless and welded ferritic and martensitic stainless steel tubing for general service
- ASTM A276 — Stainless steel bars and shapes (grade reference, UNS S40300)
- UNS S40300 — Unified Numbering System designation for 403
Japanese Standards (JIS)
- JIS G3459 — Stainless steel pipes
- JIS G4303 — Stainless steel bars (grade SUS403)
European Standards (EN)
- EN 10088-1 — Stainless steels, grade 1.4006 (X12Cr13) — chemically similar, may substitute in some applications
For pressure-purpose seamless tubes, we also supply to EN 10216-5 where applicable. Tell us your specifications and we will confirm the applicable standard for your project.
Available Sizes & Delivery
Hot-Rolled Seamless Tubes
- Outside diameter: 32–530 mm
- Wall thickness: 2.5–50 mm
- Length: up to 12,000 mm (fixed or random lengths)
Cold-Drawn / Cold-Rolled Precision Tubes
- Outside diameter: 6–114 mm
- Wall thickness: 0.5–15 mm
- Length: up to 15,000 mm (straightened and cut to tolerance)
- Ready Stock
- Common sizes ship in approximately 7 days from our warehouse
- Custom Orders
- MOQ 2–3 tons, delivery within 25–35 days
- Trial Orders
- Small trial quantities accepted for first-time evaluation
- Volume Orders
- Negotiable pricing and delivery schedules for large quantities
Chemical Composition
| Standard | Grade | C | Si | Mn | P max | S max | Cr | Ni |
|---|---|---|---|---|---|---|---|---|
| GB/T 1220 / GB/T 14975 | 12Cr12 / 1Cr12 | 0.10–0.15 | ≤1.00 | ≤1.00 | 0.040 | 0.030 | 11.50–13.00 | ≤0.60 |
| ASTM A511 / A268 | 403 (S40300) | ≤0.15 | ≤0.50 | ≤1.00 | 0.040 | 0.030 | 11.50–13.00 | ≤0.60 |
| JIS G4303 / G3459 | SUS403 | ≤0.15 | ≤0.50 | ≤1.00 | 0.040 | 0.030 | 11.50–13.00 | ≤0.60 |
The key difference between standards lies primarily in the silicon range: Chinese GB allows silicon up to 1.00%, while ASTM and JIS limit silicon to 0.50%. For applications requiring tighter silicon control or lower sulfur and phosphorus residuals, we can produce to modified specifications through our ESR remelting capability.
Manufacturing Process
Steelmaking
The steel is produced via Electric Arc Furnace melting followed by Ladle Furnace refining and Vacuum Degassing to control gas content and inclusion levels. For rotor-grade or turbine-quality material, we offer Electroslag Remelting (ESR) to achieve superior solidification structure and reduced sulfur content. For the most demanding aerospace or nuclear applications, VIM + VAR double-vacuum processing ensures the highest cleanliness levels.
Pipe Making
Solid round billets are heated and pierced to form hollow shells, then hot-rolled on a mandrel mill or pilger mill to achieve the target wall thickness. For precision tubes, the hot-rolled shell undergoes cold drawing or cold rolling through multiple passes with intermediate annealing. 12Cr12 tubes are supplied in the annealed or quenched-and-tempered condition depending on the intended application. Our cold-drawn tube and cold-rolled tube processes yield tight dimensional control and a smooth surface finish for mechanical and structural uses.
Mechanical Properties
| Standard | Condition | Tensile Strength (MPa) | Yield Strength 0.2% (MPa) | Elongation (%) | Hardness (HB) |
|---|---|---|---|---|---|
| GB/T 1220 | Quenched + Tempered | ≥590 | ≥390 | ≥18 | 170–235 |
| ASTM A276 | Annealed (Condition A) | ≥485 | ≥275 | ≥20 | ≤200 |
| ASTM A276 | Hardened + Tempered | ≥585 | ≥415 | ≥20 | 170–223 |
| JIS G4303 | Quenched + Tempered | ≥590 | ≥390 | ≥20 | 170–235 |
Mechanical properties vary with heat treatment condition and section thickness. The annealed condition maximizes ductility and machinability, while the quenched-and-tempered condition optimizes strength and hardness for structural components. Request a sample to evaluate material properties against your specifications.
Heat Treatment
| Treatment | Temperature (°C) | Holding / Method | Cooling |
|---|---|---|---|
| Annealing | 800–900 | Full anneal, hold until uniform | Slow furnace cool |
| Subcritical Anneal | 730–780 | Process anneal, ~2 hours | Air cool |
| Hardening (Austenitizing) | 950–1000 | Hold 30–60 min per 25 mm section | Oil quench or forced air |
| Tempering | 700–750 | 2 hours minimum | Rapid air cool |
The martensitic transformation of 12Cr12 is air-hardening in thin sections. Oil quenching is recommended for sections above 25 mm to achieve full hardening. Tempering must be performed promptly after quenching to prevent cracking. The tempering temperature is selected above 700°C to achieve good toughness; tempering in the 400–550°C range should be avoided as it may reduce impact properties.
Surface Finish & Tolerances
Fushun Steel Tube supplies 12Cr12 seamless tubes in a range of surface conditions. Hot-rolled tubes are delivered with a pickled or shot-blasted surface free of scale. Cold-drawn and cold-rolled tubes achieve a bright, smooth finish comparable to Ra 1.6–3.2 µm. For hydraulic and pneumatic applications, honed or skived-and-roller-burnished internal surfaces down to Ra 0.2–0.4 µm are available.
Dimensional tolerances comply with the applicable product standard. Cold-drawn precision tubes typically hold OD tolerance ±0.08 mm and WT tolerance ±10% (or better upon request). Straightness is maintained within 1 mm/m for cold-finished tubes. All tubes are end-finished square to the longitudinal axis, with beveled or plain ends as specified.
Quality Assurance & Testing
Every 12Cr12 seamless tube shipment undergoes a rigorous quality control workflow:
- Raw Material Inspection: Chemical analysis by optical emission spectrometry for every heat. Inclusion rating and grain size evaluation per applicable standards.
- In-Process Checks: Dimensional monitoring during hot rolling and cold drawing. Surface inspection for defects after each processing stage.
- Finished Product Testing: Full suite including hydrostatic or eddy current testing, ultrasonic inspection for longitudinal and transverse defects, tensile testing at room and elevated temperatures, hardness testing, impact testing, and metallographic examination.
- Certification: EN 10204 3.1 certificates as standard; 3.2 certificates available with third-party inspection upon request.
Our quality management system is ISO 9001 certified. Dedicated quality engineers oversee each production batch from melting to final dispatch.
Packing & Shipping
Seamless tubes are bundled in hexagonal or square formation with steel straps. Each tube end is protected with plastic caps or bevel protectors to prevent handling damage. For precision cold-drawn tubes, individual tubes are wrapped in anti-rust paper and packed in wooden crates with moisture-proof lining. Tube OD, WT, grade, heat number, and specification are clearly marked on each bundle or crate.
We ship worldwide via sea freight (FCL/LCL), air freight for urgent orders, and rail to Central Asia and Europe. Standard port of loading is Shanghai or Tianjin. Custom Incoterms including FOB, CIF, and DAP can be arranged. Contact us for a free quote with shipping to your destination.
Frequently Asked Questions
What size range is available for 12Cr12 stainless steel seamless tubes?
We supply 12Cr12 seamless tubes in OD 6–530 mm with WT 0.5–50 mm. Standard lengths up to 12 m for hot-rolled and 15 m for cold-drawn. Custom dimensions can be manufactured upon request with typical MOQ 2–3 tons.
What is the maximum service temperature for 12Cr12 / 403 tubes?
12Cr12 tubes can operate continuously at temperatures up to 650°C. They offer good oxidation resistance and moderate creep strength in this range, making them suitable for steam turbine blades, superheater tubes, and high-temperature valve components.
Can you supply 12Cr12 tubes with third-party inspection?
Yes. We provide EN 10204 3.1 material certificates as standard on every shipment. Third-party inspection by SGS, BV, TÜV, Lloyd’s Register, or your nominated inspector is available, with EN 10204 3.2 certification issued upon acceptance.
How does 12Cr12 compare to 410 stainless steel?
12Cr12 (403) has a lower maximum carbon content (0.15% vs. 0.15% max for 410) and is produced with tighter silicon control under ASTM/JIS, resulting in better weldability and toughness. While both are 12% Cr martensitic grades, 403 is traditionally preferred for turbine blade applications due to its superior damping capacity and proven vibration resistance.
Do you keep stock of 12Cr12 seamless tubes?
We maintain ready stock of common sizes in 12Cr12 for fast dispatch (approximately 7 days). For non-standard dimensions, we manufacture to order with delivery within 25–35 days. Tell us your specifications and we will confirm stock availability immediately.
