Project Description
17Cr16Ni2 / 1.4057 Martensitic Stainless Steel Seamless Tube
17Cr16Ni2 — also designated as 1.4057, X17CrNi16-2, AISI 431, UNS S43100, and SUS431 — is a high-chromium martensitic stainless steel with a deliberate nickel addition that sets it apart from conventional 410 and 420 grades. The 1.5–2.5% nickel content improves toughness, enhances through-hardening response in heavier sections, and delivers the best corrosion resistance of any standard martensitic stainless grade. When supplied as seamless tube by Fushun Steel Tube, this material combines the high strength and hardness characteristic of the martensitic class with noticeably better resistance to mildly aggressive environments including atmospheric exposure, fresh water, steam, and many organic media.
Fushun produces 17Cr16Ni2 seamless tube in both hot-rolled and cold-drawn/cold-rolled conditions, with standard heat treatment options of annealed (+A), QT800, and QT900. The QT800 condition delivers a minimum yield strength of 600 MPa with 14% elongation, while QT900 pushes yield strength to 700 MPa minimum for applications demanding maximum mechanical performance. Every tube is manufactured under our ISO 9001 quality system with full traceability from melt to finished product, supported by EN 10204 3.1 certification as standard. Contact us for a free quote with your dimensional and technical requirements.
Applications
The combination of high strength, good toughness, and superior martensitic corrosion resistance makes 17Cr16Ni2 seamless tube the preferred choice for mechanical components that operate under stress in mildly corrosive or wear-prone environments. Typical downstream applications include:
- Pump shafts and sleeves for centrifugal, rotary, and submersible pumps handling water, light chemicals, and hydrocarbons
- Valve stems, seats, and trim components in gate, globe, and control valves for moderate-pressure service
- Piston rods and cylinder barrels for hydraulic and pneumatic cylinders in marine, offshore, and industrial equipment
- Turbine shafts and compressor rotors for small to medium steam turbines, gas expanders, and process compressors
- Spindles and lead screws for machine tools, linear actuators, and precision positioning systems
- High-strength fasteners, studs, and bolting for flanged connections in chemical plants and power generation
- Paper mill and textile machinery components including doctor blades, roll journals, and guide rolls
- Aircraft and aerospace structural fittings where high strength-to-weight ratio and moderate corrosion resistance are required
Fushun also supplies stainless steel tube round bars and forgings in the same 17Cr16Ni2 grade for customers who require matching material across multiple product forms within a single project. Tell us your specifications and we will recommend the optimal heat treatment condition and delivery form.
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Specifications & Standards
The 17Cr16Ni2 / 1.4057 grade is defined under multiple international standards. While historically developed as a bar and forging grade, Fushun Steel Tube manufactures this material as seamless tube to the dimensional and technical delivery requirements of the applicable tube standards listed below, with chemical and mechanical properties governed by the material standards:
Material Standards (Chemical Composition & Mechanical Properties)
- EN 10088-3
- Stainless steels — Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion-resisting steels for general purposes. Designation: X17CrNi16-2, Material No. 1.4057.
- EN 10272
- Stainless steel bars for pressure purposes. Includes X17CrNi16-2 for pressure-retaining components.
- ASTM A276 / A276M
- Standard Specification for Stainless Steel Bars and Shapes. Covers UNS S43100 (Grade 431).
- ASTM A479 / A479M
- Standard Specification for Stainless Steel Bars and Shapes for Use in Boilers and Other Pressure Vessels. Includes UNS S43100.
- JIS G4303
- Stainless steel bars. Designation: SUS431.
- GOST 5632
- Russian standard for high-alloy steels and corrosion-resistant, heat-resistant and heat-strengthening alloys. Equivalent grade: 20Ch17N2 (20Х17Н2).
- GB/T 1220
- Chinese standard for stainless steel bars. Designation: 17Cr16Ni2.
Tube Product Standards
- EN 10297-2
- Seamless circular steel tubes for mechanical and general engineering purposes — Stainless steel. Applicable for mechanical tubing in 1.4057 where specified by agreement.
- ASTM A511 / A511M
- Standard Specification for Seamless Stainless Steel Mechanical Tubing. Applicable for S43100 mechanical tube in cold-worked or annealed condition.
For pressure-containing applications, Fushun can manufacture 17Cr16Ni2 tube to customer-specific technical delivery conditions drawing on the relevant material requirements of EN 10272 or ASTM A479. Contact our engineering team to discuss your application and the appropriate standard framework.
Available Sizes & Delivery
Hot-Rolled Seamless Tube
- Outer Diameter
- 6 mm – 630 mm (0.236 in – 24.8 in)
- Wall Thickness
- 0.5 mm – 60 mm (0.020 in – 2.36 in)
- Length
- 1,000 mm – 12,000 mm; custom lengths on request
Cold-Drawn / Cold-Rolled Precision Tube
- Outer Diameter
- 3 mm – 220 mm (0.118 in – 8.66 in)
- Wall Thickness
- 0.3 mm – 30 mm (0.012 in – 1.18 in)
- Length
- Up to 14,000 mm; cut-to-length available
Delivery Information
- Ready stock of common sizes in annealed condition: approximately 7 days
- Custom and non-standard sizes: MOQ 2–3 tons, delivery approximately 25–35 days
- Small trial orders for special grades and first-article qualification are welcome
- Volume production orders: negotiable pricing and scheduled delivery to match your project timeline
Fushun maintains an inventory program for frequently requested martensitic stainless tube grades. Request a sample or current stock list for 17Cr16Ni2 seamless tube.
Chemical Composition
The chemical composition of 17Cr16Ni2 / 1.4057 / 431 is defined by cast analysis (heat analysis). Minor variations exist between the EN and ASTM specifications, particularly in the permitted manganese and nickel ranges. Fushun certifies every heat to the applicable standard per the customer's purchase order requirements.
| Element | EN 10088-3 X17CrNi16-2 (1.4057) |
ASTM A276 / A479 UNS S43100 (Grade 431) |
JIS G4303 SUS431 |
GB/T 1220 17Cr16Ni2 |
|---|---|---|---|---|
| Carbon (C) | 0.12 – 0.22 | ≤ 0.20 | ≤ 0.20 | 0.12 – 0.22 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.50 | ≤ 1.00 | ≤ 1.00 | ≤ 1.50 |
| Phosphorus (P) | ≤ 0.040 | ≤ 0.040 | ≤ 0.040 | ≤ 0.040 |
| Sulfur (S) | ≤ 0.015* | ≤ 0.030 | ≤ 0.030 | ≤ 0.030 |
| Chromium (Cr) | 15.0 – 17.0 | 15.0 – 17.0 | 15.0 – 17.0 | 15.0 – 17.0 |
| Nickel (Ni) | 1.50 – 2.50 | 1.25 – 2.50 | 1.25 – 2.50 | 1.50 – 2.50 |
* Per EN 10088-3, for bars, rods, wire, sections, and bright products the sulfur limit is ≤ 0.030%. For machinability enhancement, a controlled sulfur range of 0.015–0.030% can be agreed. For weldability, a controlled range of 0.008–0.030% may be specified.
Manufacturing Process
Steelmaking
Fushun produces 17Cr16Ni2 steel using the EAF + LF + VD (Electric Arc Furnace + Ladle Furnace + Vacuum Degassing) route. The vacuum degassing step is critical for this grade: it reduces hydrogen content to prevent flaking, removes dissolved gases and non-metallic inclusions, and ensures a clean, homogeneous microstructure. For the most demanding applications — such as rotating shafts for high-speed turbines or aerospace components — we offer optional ESR (Electroslag Remelting) or VIM + VAR (Vacuum Induction Melting + Vacuum Arc Remelting) upgrades that further refine the ingot structure and enhance mechanical property consistency.
Pipe-Making
Seamless tube is produced by hot rotary piercing of round billets followed by elongation rolling on a retained-mandrel mill or Assel mill, then sized to final dimensions. For cold-drawn and cold-rolled precision tube, the hot-rolled hollow is pickled, lubricated, and cold-worked through a series of drawing or pilgering passes with intermediate annealing at 680–800 °C to restore ductility. Final heat treatment is applied per the specified condition: annealing (+A) for machinability, or quenching and tempering to QT800 or QT900 for targeted strength levels.
Mechanical Properties
The mechanical properties of 17Cr16Ni2 seamless tube depend on the heat treatment condition. Fushun supplies the material in three standard conditions: annealed (+A) for maximum machinability, QT800 for balanced strength and toughness, and QT900 for maximum strength. The values below are per EN 10088-3 for long products up to 160 mm thickness/diameter.
| Condition | Thickness (mm) | 0.2% Proof Strength Rp0.2 min. (MPa) |
Tensile Strength Rm (MPa) |
Elongation A min. (%) |
Impact Energy KV2 min. (J, long.) |
Hardness HBW (guide) |
|---|---|---|---|---|---|---|
| +A (Annealed) | All | — | ≤ 950 | — | — | ≤ 295 |
| +QT800 | ≤ 60 | 600 | 800 – 950 | 14 | 25 | — |
| +QT800 | 60 < t ≤ 160 | 600 | 800 – 950 | 12 | 20 | — |
| +QT900 | ≤ 60 | 700 | 900 – 1050 | 12 | 16 | — |
| +QT900 | 60 < t ≤ 160 | 700 | 900 – 1050 | 10 | 15 | — |
Elevated-Temperature Yield Strength
| Temperature (°C) | 100 | 150 | 200 | 250 | 300 | 350 | 400 |
|---|---|---|---|---|---|---|---|
| +QT800 | 515 | 495 | 475 | 460 | 440 | 405 | 355 |
| +QT900 | 565 | 525 | 505 | 490 | 470 | 430 | 375 |
Physical Properties
- Density
- 7.7 g/cm³ (0.278 lb/in³)
- Modulus of Elasticity
- 215 GPa at 20 °C; 190 GPa at 400 °C
- Thermal Conductivity
- 25 W/(m·K) at 20 °C
- Specific Heat Capacity
- 460 J/(kg·K) at 20 °C
- Mean Coefficient of Thermal Expansion
- 10.0 × 10⁻⁶ /K (20–100 °C); 10.5 × 10⁻⁶ /K (20–400 °C)
- Magnetic
- Yes (ferromagnetic in all heat treatment conditions)
Heat Treatment
Heat treatment is the primary control lever for the mechanical properties of 17Cr16Ni2. Fushun's in-house heat treatment furnaces with calibrated temperature control (±10 °C) and automated cycle recording ensure repeatable results batch after batch. The recommended parameters per EN 10088-3 are:
| Process | Temperature (°C) | Cooling Method | Remarks |
|---|---|---|---|
| Hot Forming | 1100 – 800 | Slow cooling in furnace or insulating media | Prevents stress cracking; direct air cooling not recommended |
| Annealing (+A) | 680 – 800 | Furnace or air | Double annealing may be applied for improved machinability and structural uniformity |
| Hardening (Austenitizing) | 950 – 1050 | Oil or air | Soaking time: approximately 30 min per 25 mm of section thickness. Oil quenching preferred for heavier sections. |
| Tempering — QT800 | Stage 1: 750 – 800 Stage 2: 650 – 700 |
Air after each stage | Two-stage tempering recommended. Holding time: minimum 1 h per stage plus 1 h per 25 mm of thickness. |
| Tempering — QT900 | 600 – 650 | Air | Single-stage temper. Holding time: minimum 1 h plus 1 h per 25 mm of thickness. |
Important: Tempering in the range of 400–550 °C should be avoided as it can result in reduced toughness (temper embrittlement). In continuous furnaces, the upper limit of the specified temperature range or slightly above is generally preferred to ensure uniform temperature distribution along the tube length.
Surface Finish & Tolerances
Fushun Steel Tube offers 17Cr16Ni2 seamless tube in a range of surface conditions to match end-use requirements. Hot-rolled tube is supplied with a black, descaled, or pickled surface depending on the downstream processing route. Cold-drawn precision tube is delivered with a bright, smooth finish (Ra ≤ 3.2 μm as standard; finer finishes to Ra ≤ 0.8 μm are available on request for hydraulic and pneumatic applications).
For components requiring enhanced surface integrity, we provide honed and polished internal surfaces (ID) for cylinder barrel applications, and centerless-ground external surfaces (OD) for shafting and spindle stock. Dimensional tolerances conform to the applicable tube standard: hot-rolled to EN 10297-2 or ASTM A511 tolerance classes, and cold-drawn precision tube to tighter h8/h9 (OD) and ±10% or better (WT) tolerances. Tighter tolerances including h6/h7 can be supplied through additional processing. Tell us your surface finish and tolerance requirements and we will confirm feasibility.
Quality Assurance & Testing
Every 17Cr16Ni2 seamless tube shipment from Fushun passes through a systematic quality control workflow designed to verify conformance to the purchase specification:
Raw Material Inspection
- 100% chemical analysis verification by optical emission spectrometry (OES) on every heat
- Ingot/billet surface inspection and conditioning prior to hot working
In-Process Controls
- Hot working temperature monitoring with furnace chart records
- Intermediate dimensional checks after piercing, elongation, and sizing
- Heat treatment cycle verification with time–temperature recorder charts
- Hardness testing after each heat treatment batch
Finished Product Testing
- Tensile testing at room temperature per ASTM A370 / EN ISO 6892-1 — one test per heat treatment batch per dimension
- Impact testing (Charpy V-notch) per EN ISO 148-1 — one set per heat treatment batch
- Hardness testing (HBW or HRC) per EN ISO 6506 / ASTM E10 — 100% for QT800/QT900 conditions
- Dimensional inspection — OD, WT, length, straightness: 100% of tubes
- NDT options: Ultrasonic testing (UT) per EN ISO 10893-10 / ASTM E213, eddy current testing (ET) per EN ISO 10893-2, and liquid penetrant testing (PT) per EN ISO 10893-4 — available on request
- Hydrostatic testing per EN 10216 series or customer specification when specified for pressure applications
- Metallographic examination — grain size, microstructure, and inclusion content per ASTM E45 / EN ISO 643 on qualification samples
All test results are compiled into an EN 10204 3.1 inspection certificate, reviewed and signed by Fushun's quality department, and shipped with the material. EN 10204 3.2 certificates with third-party witness by Lloyds, DNV, Bureau Veritas, SGS, or TUV are available on request.
Packing & Shipping
Fushun Steel Tube packs 17Cr16Ni2 seamless tube to prevent mechanical damage and surface contamination during transit. Small-diameter tubes (OD ≤ 60 mm) are bundled with steel straps, wrapped in waterproof kraft paper or polyethylene film, and secured in wooden crates or on pallets. Larger-diameter tubes and heavy-wall products are bundled with end caps or bevel protectors and shipped in open-top containers or on flat racks.
Cold-drawn precision tube is individually wrapped or interleaved with protective spacing material to preserve the bright surface finish. All shipments are clearly marked with heat numbers, specification references, and dimensional identification for full traceability at the receiving end. We ship via sea freight (FCL/LCL), air freight for urgent orders, and rail freight to inland destinations across Eurasia. Standard delivery terms are FOB Shanghai, CIF, or DAP as per the sales contract.
Frequently Asked Questions
Can Fushun supply 17Cr16Ni2 tube in the QT900 condition for diameters over 200 mm?
Yes. While the EN 10088-3 standard covers thicknesses up to 160 mm, Fushun has the metallurgical capability — including our EAF + LF + VD steelmaking route with optional ESR — to achieve QT900 properties in heavier sections. We recommend discussing your specific OD and WT combination with our technical team so we can confirm the achievable property envelope and propose an optimized heat treatment cycle.
What is the corrosion resistance of 17Cr16Ni2 compared to 304 or 316 stainless steel?
17Cr16Ni2 offers the highest corrosion resistance in the martensitic stainless family, but it does not match the pitting and crevice corrosion resistance of austenitic grades like 304 (1.4301) or 316 (1.4401). It performs well in mild atmospheric conditions, fresh water, steam, organic solvents, and many mildly acidic environments. For strong acids, chlorides, or marine immersion service, an austenitic or duplex stainless tube is recommended. Contact our technical team for a material selection review specific to your operating environment.
Do you keep 17Cr16Ni2 tube in stock?
We maintain inventory of commonly requested sizes in the annealed condition for rapid dispatch within approximately 7 days. For QT800 and QT900 conditions, finished stock is limited because the tempering temperature varies by customer specification; we typically heat-treat to order, which adds approximately 5–7 days to the standard 25–35 day production lead time for non-stock sizes.
Is 17Cr16Ni2 weldable for tube-to-tube or tube-to-fitting joints?
17Cr16Ni2 is considered weldable with appropriate precautions. Preheating to 200–300 °C is recommended before welding, and post-weld heat treatment (annealing or tempering) is generally required to restore toughness in the heat-affected zone. Austenitic stainless filler metals such as E309L or ER309L are often selected to improve joint ductility. We recommend qualifying the welding procedure on sample material before production welding.
Can you provide matching round bars or forgings in the same heat of 17Cr16Ni2?
Absolutely. Fushun supplies round bars in diameters from 10 mm to 500 mm, and custom open-die forgings to customer drawings, in the same 17Cr16Ni2 grade. Where matched-property requirements exist (e.g., a shaft machined from bar that must have identical mechanical properties to a tube sleeve on the same assembly), we can coordinate production from a single heat to ensure chemical and property consistency across all product forms.