Project Description
14Cr17Ni2 (1Cr17Ni2, AISI 431, SUS431) Stainless Steel Seamless Tube
14Cr17Ni2 — also designated under the older Chinese standard as 1Cr17Ni2, and internationally recognized as AISI 431 / UNS S43100, SUS431 (JIS), and X17CrNi16-2 / 1.4057 (EN) — is a martensitic stainless steel engineered for applications that demand both high mechanical strength and reliable corrosion resistance. As a seamless tube product, it delivers the structural integrity and uniformity essential for rotating components, pressure-containing parts, and precision-machined assemblies.
With a chromium content of 16–18% and nickel at 1.50–2.50% (under GB), this grade achieves a tensile strength exceeding 1,080 MPa after quenching and tempering, placing it among the strongest martensitic stainless steels available in tubular form. Its hardenability extends through relatively thick sections, and it responds predictably to conventional heat treatment cycles. At Fushun Steel Tube, 14Cr17Ni2 seamless tubes are produced through our integrated steelmaking and pipe-making route — from EAF + LF + VD refining to hot-rolled or cold-drawn finishing — giving customers full traceability from melt to final product.
Compared to standard austenitic grades like 304 or 316, 14Cr17Ni2 offers substantially higher strength at a lower alloy cost, making it a practical choice when mechanical load-bearing capacity outweighs the need for maximum pitting resistance. Contact us for a free quote with your required dimensions and delivery condition.
Product Overview
Fushun Steel Tube supplies 14Cr17Ni2 stainless steel seamless tube in both hot-rolled and cold-drawn/cold-rolled conditions. Tubes are available in the annealed, quenched-and-tempered, or solution-treated state depending on the downstream processing requirements. Our manufacturing capability spans standard and non-standard dimensions, with ready stock maintained for the most frequently requested sizes.
Applications
The combination of high tensile strength, good toughness, and moderate corrosion resistance makes 14Cr17Ni2 seamless tube a reliable choice across multiple industries. Typical end-use components manufactured from this grade include:
- Pump shafts and propeller shafts — for marine propulsion systems, centrifugal pumps, and industrial fluid-handling equipment
- Piston rods and valve stems — in hydraulic cylinders, pneumatic actuators, and process control valves
- Aircraft structural components and fasteners — where high strength-to-weight ratio and corrosion resistance are specified
- Beater bars and doctor blades — for pulp and paper machinery operating in wet, mildly corrosive environments
- High-strength bolts, studs, and threaded components — heat-treated to ASTM F593/F738M specifications
- Laboratory and food-processing equipment parts — shafts, spindles, and wear components exposed to organic acids and salt solutions
- Rotating machinery components — turbine shafts, compressor rotors, and centrifuge spindles
When your application requires dimensional precision beyond standard hot-rolled tolerances, our cold-drawn steel tube process can achieve tighter OD and WT control with improved surface finish. For general mechanical engineering uses, stainless steel tube in other grades may also be suitable — tell us your specifications and our engineers will recommend the optimal material.
Specifications & Standards
Multiple national and international standards cover 14Cr17Ni2 and its equivalents across different product forms. For seamless tube and pipe applications, the following standards are most relevant:
Seamless Tube & Pipe Standards
- GB/T 14976 — Stainless steel seamless tubes for fluid transport (China)
- ASTM A511 — Seamless stainless steel mechanical tubing (USA)
- EN 10216-5 — Seamless steel tubes for pressure purposes — stainless steel tubes
- EN 10297-2 — Seamless circular steel tubes for mechanical and general engineering purposes — stainless steel
Bar, Forging & General Standards (Materials Reference)
- GB/T 1220 — Stainless steel bars (14Cr17Ni2 / 1Cr17Ni2)
- ASTM A276 / A276M — Stainless steel bars and shapes (S43100 / 431)
- JIS G4303 — Stainless steel bars (SUS431)
- EN 10088-3 — Stainless steels — technical delivery conditions for semi-finished products, bars, rods, and wire (1.4057 / X17CrNi16-2)
- ASTM F593 / F738M — Stainless steel bolts, hex cap screws, and studs (C3-80, C3-120 sourced from S43100)
- AMS 5628 — Aerospace specification for 431 stainless steel bars and forgings
- DIN 17440 — Stainless steels — technical delivery conditions (legacy, superseded by EN 10088)
Note that composition limits vary slightly between standards — the Chinese GB specification sets a tighter carbon range (0.11–0.17%) and a slightly higher chromium range (16.00–18.00%) compared to ASTM and JIS. When ordering, specify the governing standard so we can certify the material accordingly.
Available Sizes & Delivery
| Process | OD Range (mm) | WT Range (mm) | Length (m) |
|---|---|---|---|
| Hot-Rolled Seamless | 6 – 426 | 1 – 50 | Up to 12.0 (fixed or random) |
| Cold-Drawn / Cold-Rolled | 6 – 219 | 0.5 – 20 | Up to 12.0 (fixed or random) |
| Honed Tube (ID Finished) | 20 – 320 | 2 – 40 | Up to 10.0 |
Delivery Information
- Ready Stock (Common Sizes)
- Approximately 7 days from order confirmation. Standard sizes in annealed or quenched-and-tempered condition are maintained in inventory.
- Custom / Non-Standard Orders
- Minimum order quantity: 2–3 metric tons. Delivery: ~25–35 days, depending on the billet availability and heat treatment schedule.
- Trial & Small Orders
- Small trial quantities are accepted for special grades and non-standard specifications. Pricing may carry a small-lot surcharge.
- Volume Orders
- For quantities above 20 tons, contact us for negotiated pricing and delivery scheduling.
Chemical Composition
The following table compares the chemical composition requirements across the major standards covering this grade. The GB specification (14Cr17Ni2) is the most restrictive on carbon range, while EN 1.4057 allows a wider manganese range for improved hot workability.
| Element | GB 14Cr17Ni2 (GB/T 1220) |
ASTM S43100 (ASTM A276) |
JIS SUS431 (JIS G4303) |
EN 1.4057 (EN 10088-3) |
|---|---|---|---|---|
| Carbon (C) | 0.11 – 0.17 | ≤ 0.20 | ≤ 0.20 | 0.12 – 0.22 |
| Silicon (Si) | ≤ 0.80 | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Manganese (Mn) | ≤ 0.80 | ≤ 1.00 | ≤ 1.00 | ≤ 1.50 |
| Phosphorus (P) | ≤ 0.035 | ≤ 0.040 | ≤ 0.040 | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 | ≤ 0.015* |
| Chromium (Cr) | 16.00 – 18.00 | 15.00 – 17.00 | 15.00 – 17.00 | 15.00 – 17.00 |
| Nickel (Ni) | 1.50 – 2.50 | 1.25 – 2.50 | 1.25 – 2.50 | 1.50 – 2.50 |
* EN 1.4057 sulfur limit of ≤0.015% applies to standard product forms. For improved machinability, sulfur may be controlled to 0.015–0.030% by agreement. All values are heat (ladle) analysis. Product analysis tolerances apply per the respective standard.
Manufacturing Process
Fushun Steel Tube produces 14Cr17Ni2 seamless tube through a vertically integrated manufacturing route. The steel is melted in an electric arc furnace, refined through ladle furnace treatment, and vacuum degassed to achieve low gas content and optimal cleanliness — critical for a martensitic grade where inclusions can act as crack initiation sites during quenching. For applications requiring the highest cleanliness levels, electroslag remelting (ESR) or vacuum induction melting plus vacuum arc remelting (VIM + VAR) upgrades are available.
The cast ingot or continuous cast round billet is forged or pierced and hot-rolled into a hollow shell, then sized to the ordered OD and wall thickness. For precision applications, the hot-rolled tube undergoes subsequent cold-drawing or cold-rolling passes to achieve tighter dimensional tolerances, improved surface finish, and enhanced mechanical properties through strain hardening. The final tube is heat-treated to the specified delivery condition — typically annealed or quenched-and-tempered — and undergoes full inspection before shipment.
Mechanical Properties
Mechanical properties of 14Cr17Ni2 seamless tube depend significantly on the heat treatment condition. The table below summarizes the minimum guaranteed properties under the major standards. For tube-specific mechanical requirements, values are verified on test rings or longitudinal strip specimens cut from the finished tube wall.
| Standard | Condition | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (HB) | Impact (J) |
|---|---|---|---|---|---|---|
| GB/T 1220 | Quenched & Tempered | ≥ 1,080 | — | ≥ 10 | — | ≥ 39 (Akv) |
| GB/T 1220 | Annealed | — | — | — | ≤ 285 | — |
| ASTM A276 | Annealed (Condition A) | — | — | — | ≤ 285 | — |
| ASTM A276 | Condition T (QT) | 850 – 1,000 | — | — | 250 – 320 | — |
| JIS G4303 | Quenched & Tempered | ≥ 780 | ≥ 590 | ≥ 15 | ≥ 229 | — |
| EN 10088-3 | +QT800 | 800 – 950 | ≥ 600 | ≥ 14 | — | ≥ 25 (ISO-V) |
| EN 10088-3 | +QT900 | 900 – 1,050 | ≥ 700 | ≥ 12 | — | ≥ 16 (ISO-V) |
In practice, properly heat-treated 14Cr17Ni2 seamless tube can achieve tensile strengths up to 1,350 MPa with tempering at approximately 430°C. However, tempering in the 425–600°C range must be avoided or carefully controlled, as this grade exhibits a marked drop in impact toughness within this temperature window due to temper embrittlement phenomena. For applications requiring both high strength and good toughness, Fushun recommends tempering at 275–350°C (for maximum strength) or above 600°C (for balanced properties). Request a sample for mechanical testing to validate properties against your requirements.
Heat Treatment
Proper heat treatment is essential to achieving the target mechanical properties in 14Cr17Ni2. The recommended parameters below are drawn from the applicable material standards and verified through Fushun's production experience.
| Process | Standard | Temperature (°C) | Holding | Cooling |
|---|---|---|---|---|
| Annealing | GB/T 1220 | 680 – 700 | High-temperature tempering cycle | Air cool |
| Process Anneal | ASTM A276 | 620 – 660 | Section-dependent | Air cool |
| Annealing (+A) | EN 10088-3 | 680 – 800 | Section-dependent; double anneal may be advisable | Furnace or air |
| Quenching | GB / ASTM / EN | 950 – 1,050 | ~30 min per 25 mm section | Oil or forced air |
| Tempering (high strength) | GB/T 1220 | 275 – 350 | 2 h minimum | Air cool |
| Tempering +QT800 | EN 10088-3 | 750 – 800, then 650 – 700 | Two-stage; hold at each | Air cool after each |
| Tempering +QT900 | EN 10088-3 | 600 – 650 | 2 h minimum | Air cool |
| Preheat (before welding) | — | 200 – 300 | Uniform through wall | Maintain interpass |
| Post-Weld Heat Treatment | — | ~650 | 1 h per 25 mm | Slow cool |
Important: Avoid tempering 14Cr17Ni2 in the 425–600°C range, as the material is susceptible to reversible temper embrittlement. Impact toughness can drop by 50% or more in this window. If service temperatures fall within this range, consult our technical team for alternative heat treatment strategies.
Surface Finish & Tolerances
Fushun Steel Tube supplies 14Cr17Ni2 seamless tube with a range of surface finishes to meet different application needs. Hot-rolled tubes are delivered with a black or pickled surface, free from heavy scale and surface defects. Cold-drawn and cold-rolled tubes feature a bright, smooth finish suitable for direct machining or minimal stock removal. For hydraulic cylinder and piston rod applications, honed or SRB-finished tubes are available with ID tolerances as tight as IT7 and surface roughness Ra ≤ 0.4 µm.
Dimensional tolerances conform to the governing tube standard: hot-rolled tubes to ±0.75% of OD (minimum ±0.3 mm) and ±10% of WT; cold-drawn tubes to ±0.10–0.30 mm on OD and ±5–8% on WT depending on the size category. Straightness is maintained within 1.5 mm/m for cold-finished tubes. End finish options include plain-end, beveled, or threaded to customer specification.
Quality Assurance & Testing
Raw Material Inspection
Every heat of 14Cr17Ni2 steel undergoes optical emission spectrometry for full chemical analysis. The melt is verified against the ordered standard before being released for pipe-making. For critical applications, inclusion ratings per ASTM E45 or ISO 4967 are available.
In-Process Controls
During hot rolling and cold drawing, dimensional checks are performed at each process stage. Wall thickness is monitored continuously via ultrasonic gauging on the cold-drawing line. Heat treatment furnace temperatures are logged and verified against the prescribed cycle.
Finished Product Testing
- Tensile testing at room temperature per ASTM A370 / ISO 6892-1 — yield strength, tensile strength, elongation
- Hardness testing — Brinell (HBW) or Rockwell (HRC) per the applicable standard
- Impact testing — Charpy V-notch at room temperature per ASTM E23 / ISO 148-1
- Hydrostatic test — each tube tested at 1.5× design pressure or per standard requirement
- Non-destructive testing — ultrasonic (UT) or eddy current (ET) for longitudinal and transverse flaw detection per EN 10246 or ASTM E213
- Dimensional inspection — 100% OD/WT/length verification, with statistical process control on production lots
- Metallographic examination — grain size, microstructure, and decarburization depth when specified
- Intergranular corrosion test — per ASTM A262 or ISO 3651-2 when required
All shipments include an EN 10204 Type 3.1 inspection certificate as standard. Type 3.2 certificates endorsed by LR, BV, DNV, TÜV, or SGS are available on request. Our quality management system is certified to ISO 9001.
Packing & Shipping
Cold-drawn and precision 14Cr17Ni2 tubes are individually wrapped in corrosion-inhibiting paper and packed in seaworthy wooden crates or steel-framed boxes. Hot-rolled tubes above 60 mm OD are bundled with steel strapping, with end caps fitted to protect bevels and prevent foreign matter ingress. Each bundle or crate carries a durable tag listing the heat number, specification, dimensions, and net weight for full traceability.
Shipments depart from major Chinese ports (Shanghai, Tianjin, Ningbo, Guangzhou) via sea freight, with air freight available for urgent orders. Standard delivery terms are FOB or CIF; other Incoterms can be arranged. Transit time to major European ports is approximately 28–35 days; to North American West Coast ports, 18–22 days. Contact us for a shipping estimate to your destination.
Frequently Asked Questions
- What size range is available for 14Cr17Ni2 stainless steel seamless tube?
- We supply 14Cr17Ni2 seamless tube in OD 6–426 mm, wall thickness 0.5–50 mm, and lengths up to 12 m. Cold-drawn precision tubes are available in OD 6–219 mm with tighter tolerances for demanding applications such as hydraulic cylinder barrels and pump shafts.
- What are the equivalent grades to 14Cr17Ni2?
- 14Cr17Ni2 (old designation 1Cr17Ni2) is equivalent to AISI 431 / UNS S43100 under ASTM, SUS431 under JIS, and X17CrNi16-2 / 1.4057 under EN standards. All are martensitic stainless steels capable of heat treatment for high strength. Minor composition differences between standards are accommodated through melt adjustments at the steelmaking stage.
- What delivery condition should I specify — annealed or quenched-and-tempered?
- If you plan to machine the tube extensively before heat treatment, order in the annealed condition (HB ≤ 285) for optimal machinability. If the tube will be used with minimal post-processing, specify quenched-and-tempered to your target strength level. We can supply to +QT800, +QT900, or custom property ranges.
- How does 14Cr17Ni2 compare to 410 or 304 stainless steel for shaft applications?
- Compared to 410 (12% Cr martensitic), 14Cr17Ni2 offers higher strength and better corrosion resistance due to the added nickel and higher chromium. Compared to 304 (austenitic), 14Cr17Ni2 provides roughly twice the yield strength after heat treatment — a decisive advantage for load-bearing shafts — though with lower general corrosion resistance. It is the preferred choice when mechanical load capacity is the primary design driver.
- Do you supply 14Cr17Ni2 round bars and forgings in addition to tube?
- Yes. Fushun supplies matching-grade round bars (OD 5–300 mm) and forged components in 14Cr17Ni2 / AISI 431 for integrated procurement. This ensures consistent chemical and mechanical properties across tube and solid components within the same assembly.