Project Description
12Cr5Mo (AISI 502 / UNS S50200 / STBA25) Seamless Alloy Steel Tube
12Cr5Mo, also designated as 1Cr5Mo, AISI 502, UNS S50200, JIS STBA25, and GOST 15X5M (15Х5М), is a 5Cr-0.5Mo ferritic alloy steel engineered for sustained high-temperature service in aggressive environments. With approximately 5% chromium and 0.5% molybdenum, this grade delivers superior oxidation resistance and creep strength at temperatures up to 600°C (1112°F). Fushun Steel Tube supplies 12Cr5Mo seamless tubes manufactured under ASTM A335 P5, ASTM A213 T5, JIS G3462 STBA25, and GB 5310 standards, with a full complement of EN 10204 3.1/3.2 certification. Whether you need furnace tubes for a refinery turnaround, superheater tubes for a power plant, or heat exchanger tubing for petrochemical processing, our 12Cr5Mo products are produced from EAF + LF + VD steel with optional electroslag remelting for demanding applications.
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Applications
The 5Cr-0.5Mo composition of 12Cr5Mo makes it the material of choice across high-temperature segments where resistance to oxidation and sulfur-bearing atmospheres is critical:
- Petroleum Refining: Crude heater tubes, catalytic reformer tubes, hydroprocessing furnace tubes, coker heater tubes, and transfer line piping operating in the 450–600°C range.
- Petrochemical Processing: Ethylene cracker furnace tubes, steam methane reformer pigtails, and heat exchanger bundles handling hot hydrocarbons with elevated sulfur content.
- Power Generation: Boiler superheater and reheater tubes, high-temperature steam piping, and economizer inlet headers where sustained metal temperatures exceed the capability of 1.25Cr-0.5Mo and 2.25Cr-1Mo grades.
- Ammonia & Fertilizer Plants: Secondary reformer outlet tubes, waste heat boiler tubes, and high-temperature transfer lines in synthesis gas service.
- Heat Exchanger Manufacturing: U-bend heat exchanger tubes for shell-and-tube exchangers in high-temperature, corrosive fluid services.
For precision cold-drawn tube requirements in critical instrumentation and mechanical applications, explore our cold-drawn steel tube capabilities. Applications requiring enhanced corrosion resistance at elevated temperatures may also benefit from our stainless steel tube portfolio.
Specifications & Standards
12Cr5Mo and its international equivalents are covered by multiple tube and pipe standards. Fushun Steel Tube certifies to each of the following, with EN 10204 3.1 or 3.2 documentation as required:
Seamless Pipe Standards
- ASTM A335 Grade P5 — Seamless ferritic alloy-steel pipe for high-temperature service
- GB 5310 12Cr5Mo — Seamless steel tubes and pipes for high-pressure boiler
- GB 9948 12Cr5Mo — Seamless steel tubes for petroleum cracking
- GB 6479 12Cr5Mo — Seamless steel tubes for high-pressure chemical fertilizer equipment
Seamless Tube Standards
- ASTM A213 Grade T5 — Seamless ferritic alloy-steel boiler, superheater, and heat-exchanger tubes
- JIS G3462 STBA25 — Alloy steel tubes for boiler and heat exchanger
- GOST 20072 15X5M — Heat-resistant steel technical specifications (Russian standard)
Related European Standards
- EN 10216-2 X11CrMo5 — Seamless steel tubes for pressure purposes, non-alloy and alloy steel tubes with specified elevated temperature properties
For applications requiring alternative tube configurations, our boiler tube line includes complementary grades across the Cr-Mo alloy spectrum. Contact us for a free quote with your target standard and dimensions.
Available Sizes & Delivery
Size Range
| Manufacturing Process | Outside Diameter (mm) | Wall Thickness (mm) | Length (m) |
|---|---|---|---|
| Hot-rolled seamless | 32–610 | 3.0–50 | 4–12 (random or fixed) |
| Cold-drawn seamless | 6–219 | 0.5–20 | Up to 15 (straightened) |
| Cold-rolled seamless | 6–114 | 0.5–12 | Up to 18 (straight lengths) |
Delivery & Minimum Order
- Ready stock (common sizes)
- Approximately 7 days from order confirmation. Suitable for urgent maintenance and turnaround projects.
- Custom / non-standard production
- Minimum order quantity 2–3 tons, with a lead time of approximately 25–35 days depending on steelmaking scheduling and finishing requirements.
- Small trial orders
- Accepted for special-grade qualification and first-article inspection. Tell us your specifications and we will work out a trial program.
- Volume orders
- Negotiable pricing and consolidated delivery arrangements. Contact our commercial team for project-based quotations.
Chemical Composition
The chemical composition of 12Cr5Mo is tightly controlled during the EAF + LF + VD steelmaking process. Fushun Steel Tube performs optical emission spectrometry on every heat to verify conformance before tube production begins.
| Element | GB 5310 12Cr5Mo | ASTM A335 P5 | ASTM A213 T5 | JIS G3462 STBA25 |
|---|---|---|---|---|
| Carbon (C) | 0.08–0.15 | ≤0.15 | ≤0.15 | ≤0.15 |
| Manganese (Mn) | 0.30–0.60 | 0.30–0.60 | 0.30–0.60 | 0.30–0.60 |
| Silicon (Si) | ≤0.50 | ≤0.50 | ≤0.50 | ≤0.50 |
| Chromium (Cr) | 4.00–6.00 | 4.00–6.00 | 4.00–6.00 | 4.00–6.00 |
| Molybdenum (Mo) | 0.45–0.65 | 0.45–0.65 | 0.45–0.65 | 0.45–0.65 |
| Phosphorus (P) | ≤0.025 | ≤0.025 | ≤0.025 | ≤0.030 |
| Sulfur (S) | ≤0.015 | ≤0.025 | ≤0.025 | ≤0.030 |
| Nickel (Ni), max | — | — | — | — |
Note: The GB 5310 standard imposes a tighter sulfur limit (0.015% max) compared to ASTM and JIS specifications, reflecting Chinese boiler code requirements for improved elevated-temperature properties. For applications specifying EN 10216-2 X11CrMo5, a similar composition applies with minor adjustments to residual element limits. Request a sample certificate for your specific standard requirements.
Manufacturing Process
Fushun Steel Tube produces 12Cr5Mo seamless tubes through an integrated manufacturing route that begins with electric arc furnace melting followed by ladle furnace refining and vacuum degassing. This triple-refinement sequence ensures low gas content, tight composition control, and clean inclusion morphology before the steel is continuously cast into round billets or, for demanding applications, electroslag-remelted into premium-quality ingots.
Pipe-making proceeds via hot-rolling on a retained-mandrel mill for mid-to-large diameters or a plug mill for smaller diameters, with online normalizing as needed. For tighter dimensional tolerances and enhanced surface finish, tubes undergo subsequent cold-drawing through multiple passes with intermediate bright annealing, or cold-rolling on pilger mills. Every heat is tracked through manufacturing with a unique identification number, enabling full traceability from the cast billet to the final tube delivered to the customer.
For precision tube applications requiring controlled OD and WT with superior surface quality, our cold-rolled steel tube process achieves tolerances as tight as ±0.05mm on wall thickness.
Mechanical Properties
Mechanical properties are verified through tensile testing on every production lot. The values below represent minimum requirements in the normalized and tempered condition, which is the standard delivery condition for 12Cr5Mo tubes.
| Property | GB 5310 12Cr5Mo | ASTM A335 P5 | ASTM A213 T5 | JIS G3462 STBA25 |
|---|---|---|---|---|
| Tensile Strength (MPa) | ≥390 | ≥415 | ≥415 | ≥410 |
| Yield Strength (MPa) | ≥205 | ≥205 | ≥205 | ≥205 |
| Elongation (%) | ≥22 (longitudinal) | ≥22 (longitudinal) | ≥30 (longitudinal) | ≥22 (longitudinal) |
| Hardness | ≤170 HBW | — | ≤170 HBW / ≤87 HRB | ≤170 HBW |
| Delivery Condition | Normalized + Tempered | Normalized + Tempered (or full anneal) | Normalized + Tempered (or full anneal) | Normalized + Tempered |
ASTM A213 T5 specifies a higher elongation minimum (30%) reflecting its focus on thinner-walled heat exchanger tubing, where ductility and workability during bending and expanding are more critical than in heavy-wall pipe applications.
Heat Treatment
Proper heat treatment is essential to achieving the target microstructure of ferrite with finely distributed carbides, which governs both short-term mechanical properties and long-term creep performance. Fushun Steel Tube operates calibrated, multi-zone heat treatment furnaces with full time-temperature chart recording for every lot.
| Heat Treatment | Temperature Range | Holding Time | Cooling Method |
|---|---|---|---|
| Normalizing | 900–960°C | Minimum 1 minute per mm of wall thickness; 30-minute floor | Still air or forced air cooling |
| Tempering | 700–750°C | Minimum 2 minutes per mm of wall thickness; 1-hour floor | Still air cooling |
| Full Anneal (alternative) | 840–880°C | As above for normalizing | Furnace cooling to ≤300°C |
| Stress Relief (post-fabrication) | 650–720°C | Minimum 1 hour per 25mm of thickness | Slow cool in still air |
Important: Unlike higher-chromium ferritic grades such as P9 and P91, 12Cr5Mo does not require isothermal annealing or precise cooling-rate control. This simplifies both mill heat treatment and field post-weld heat treatment, reducing turnaround time for maintenance projects.
Surface Finish & Tolerances
Fushun Steel Tube supplies 12Cr5Mo tubes in a range of surface conditions matched to the end use. Hot-rolled tubes are delivered with a mill-scale surface acceptable for most high-temperature structural and piping applications. For heat exchanger tubing and applications requiring close fit-up, cold-drawn and cold-rolled tubes achieve matte to bright finishes with a surface roughness of Ra 0.8–3.2 µm.
Dimensional tolerances meet or exceed the governing standard’s requirements. Typical cold-drawn tube tolerances are OD ±0.10mm (for OD ≤ 30mm) and WT ±7.5% of nominal, with tighter options available on request. Straightness is controlled to 0.0015 times the tube length for cold-finished products. End finishing options include plain ends, beveled ends for butt welding (per ASME B16.25), and threaded ends with couplings for smaller-diameter instrumentation tubes.
For applications requiring honed or polished internal surfaces — common in hydraulic cylinder service — our integrated finishing capability handles tubes up to 12m in length. Internal surface finish down to Ra 0.2 µm is achievable for critical sealing surface requirements.
Quality Assurance & Testing
Every 12Cr5Mo tube delivered by Fushun Steel Tube passes through a comprehensive quality control workflow aligned with ISO 9001 requirements:
- Raw Material Inspection
- Certified mill billets with full cast analysis. Supplemental check analysis performed on every incoming heat using optical emission spectrometry.
- In-Process Checks
- Dimensional verification at each manufacturing stage. Hot-rolling and cold-drawing parameters monitored and recorded in real time. Surface condition inspected visually and with eddy current for cold-finished products.
- Finished Product Testing
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- Hydrostatic Test: Performed to 1.5× design pressure or as specified in the governing standard. All tubes are hydrostatically tested unless NDT is substituted per customer agreement.
- Nondestructive Testing: Ultrasonic testing (UT) per ASTM E213 / EN 10246-7 or eddy current testing (ET) per ASTM E426 / EN 10246-3. Available for 100% of production length.
- Tensile Test: Room-temperature tensile testing per lot, with elevated-temperature tensile testing available on request for design validation.
- Hardness Test: Brinell or Rockwell per applicable standard.
- Flattening / Flaring / Bend Test: Performed per ASTM A450 / A999 or equivalent to verify ductility and freedom from laminations.
- Metallographic Examination: Grain size, microstructure, and inclusion rating per ASTM E112 / E45.
- Dimensional Inspection: Full OD, WT, and length verification with calibrated instruments. Ovality and straightness checked on every finished tube.
- Certification
- EN 10204 Type 3.1 inspection certificate as standard; Type 3.2 with third-party witness available. Certificates include chemical analysis, mechanical test results, hydrostatic/NDT results, and heat treatment charts.
- Positive Material Identification (PMI)
- Available on request using portable XRF or OES for on-site alloy verification. Particularly valuable for mixed-alloy turnaround projects where material mix-up risk must be eliminated.
Packing & Shipping
All 12Cr5Mo tubes are packed to prevent damage, contamination, and corrosion during transit. Standard packing uses bundled strapping with protective end caps on beveled or threaded ends. Cold-drawn and cold-rolled tubes receive additional protection: each tube is individually wrapped in corrosion-inhibiting paper and packed in seaworthy wooden crates with moisture-absorbing desiccant packs.
Tubes ship from our facility via ocean freight (FCL or LCL), air freight for urgent orders, rail freight for inland destinations, or express courier for small samples and trial quantities. Each shipment is accompanied by a detailed packing list identifying every bundle by heat number and specification. Contact us for a free quote with your delivery destination and preferred shipping method.
Frequently Asked Questions
- What size range is available for 12Cr5Mo seamless tubes?
- 12Cr5Mo tubes are available from OD 6mm to 610mm with wall thicknesses from 0.5mm to 50mm. Cold-drawn precision tubes typically cover OD 6–219mm; hot-rolled pipes cover larger diameters from 32–610mm. Lengths range from 4m to 15m depending on the manufacturing process.
- What is the maximum service temperature of 12Cr5Mo / STBA25?
- 12Cr5Mo (AISI 502) retains adequate strength and oxidation resistance up to approximately 600°C (1112°F) in continuous service. This makes it suitable for furnace tubes, superheater tubes, and refinery heater tubes. For intermittent service or thin-wall applications, consult our engineering team for a temperature derating assessment.
- How does 12Cr5Mo compare to 15CrMo (T11/P11) or 12Cr2Mo (T22/P22)?
- 12Cr5Mo provides significantly higher oxidation resistance than 15CrMo (1.25Cr-0.5Mo) and a meaningful upgrade over 12Cr2Mo (2.25Cr-1Mo) in sulfur-rich environments due to its 5% chromium content. However, 12Cr2Mo offers higher creep strength at temperatures above 550°C. Selection should balance the oxidation environment against the required stress-rupture life for the application.
- What is the typical lead time for non-stock 12Cr5Mo tubes?
- Custom production requiring new steelmaking typically takes 25–35 days from order confirmation through delivery, with a minimum order quantity of 2–3 tons. For urgent requirements, we maintain strategic billet inventory for common 12Cr5Mo specifications that can reduce lead time to approximately 15 days. Small trial orders are always welcome for first-article qualification.
- Can Fushun Steel Tube supply 12Cr5Mo tubes with third-party inspection?
- Yes. EN 10204 Type 3.2 certification with third-party witness inspection from ABS, Bureau Veritas, DNV, Lloyd’s Register, SGS, or TÜV is available. The witnessing agency can be nominated by the customer or selected from our approved inspection partners. All testing — chemical, mechanical, NDT, and hydrostatic — is witnessed and endorsed on the inspection certificate.
