Project Description
S43400 / 434 / X6CrMo17-1 Ferritic Stainless Steel Seamless Tube
S43400 (designated 434 under AISI/SAE, X6CrMo17-1 / 1.4113 under EN, and SUS434 under JIS) is a molybdenum-alloyed ferritic stainless steel that delivers measurably better corrosion resistance than standard Type 430. The deliberate molybdenum addition raises pitting resistance in chloride-bearing environments while keeping the alloy nickel-free — making it a cost-effective alternative to austenitic stainless grades where stress corrosion cracking is the primary failure mechanism.
As a seamless tube, S43400 combines the structural integrity of a wrought pipe-making process with the material’s natural magnetic properties, good thermal conductivity, and low thermal expansion relative to austenitics. These characteristics make it well-suited for heat exchanger tubing, chemical transfer lines, automotive exhaust components, and industrial equipment where moderate corrosion resistance must be paired with dimensional stability across thermal cycles.
Fushun Steel Tube manufactures S43400 seamless tubes from EAF + LF + VD refined billets, with optional electroslag remelting for demanding service conditions. Every heat is traceable to its mill certificate, and full NDT is standard on finished tubes.
Product Appearance
Applications
- Automotive exhaust systems — muffler tubing, catalytic converter shells, and EGR cooler tubes where oxidation resistance at elevated temperatures is required
- Chemical processing equipment — transfer lines, reactor cooling coils, and instrument tubing handling mildly corrosive media
- Heat exchangers and condensers — shell-and-tube exchangers in petroleum refining, petrochemical, and power generation plants
- Food and beverage processing — sanitary tubing for dairy, brewing, and food-grade transfer lines where moderate corrosion resistance suffices
- Water treatment and desalination — brine heater tubes and brackish water transfer piping
- Oil and gas downstream — heat exchanger tubes in refinery overhead condensers and crude preheat trains
- Power generation — feedwater heater tubing and condenser tubes in fossil-fuel and nuclear balance-of-plant systems
- Mechanical and structural — machine components, bushings, and shaft sleeves requiring magnetic response
For applications requiring enhanced formability or higher corrosion resistance, explore our full range of cold-drawn stainless tubes or stainless steel tube products. Contact us for a free quote with your target dimensions and service conditions.
Specifications & Standards
S43400 / 434 / X6CrMo17-1 seamless tubes are manufactured and certified to internationally recognized standards. Coverage includes seamless tubular products for general corrosion service, pressure equipment, and mechanical engineering applications.
| Standard | Scope | Product Type |
|---|---|---|
| ASTM A268 / A268M | Seamless and welded ferritic and martensitic stainless steel tubing for general service | Seamless tube |
| ASTM A269 / A269M | Seamless and welded austenitic stainless steel tubing for general service (applicable by agreement) | Seamless tube |
| EN 10216-5 | Seamless steel tubes for pressure purposes — stainless steels | Seamless pressure tube |
| EN 10297-2 | Seamless circular steel tubes for mechanical and general engineering purposes — stainless steel | Seamless mechanical tube |
| JIS G3463 | Stainless steel boiler and heat exchanger tubes | Seamless heat exchanger tube |
| DIN 17456 | Seamless circular stainless steel tubes (superseded by EN 10216-5) | Seamless tube |
| ISO 2604-2 | Steel products for pressure purposes — wrought seamless tubes | Seamless pressure tube |
For pressure service, S43400 seamless tubes are typically supplied to EN 10216-5. For mechanical applications, EN 10297-2 applies. Tell us your specifications and we will prepare a compliance matrix for your project.
Available Sizes & Delivery
Fushun Steel Tube produces S43400 seamless tubes through hot-rolled and cold-drawn/cold-rolled routes, covering the dimensional ranges below. All sizes are available in random lengths or cut-to-length per customer requirements.
| Manufacturing Route | OD Range | WT Range | Length |
|---|---|---|---|
| Hot-rolled seamless | 32 mm – 610 mm (1.26 in – 24 in) | 2.5 mm – 50 mm (0.098 in – 2 in) | Up to 12 m (40 ft) |
| Cold-drawn seamless | 6 mm – 219 mm (0.236 in – 8.625 in) | 0.5 mm – 20 mm (0.020 in – 0.787 in) | Up to 18 m (60 ft) |
| Cold-rolled precision | 6 mm – 120 mm (0.236 in – 4.724 in) | 0.5 mm – 12 mm (0.020 in – 0.472 in) | Up to 15 m (50 ft) |
Delivery Information
- Ready stock (common sizes)
- Approximately 7 days from order confirmation.
- Custom / non-standard dimensions
- Minimum order quantity 2–3 tons. Typical delivery 25–35 days.
- Trial orders
- Small trial quantities accepted for special-grade S43400 tubes. Contact us for a feasibility assessment.
- Volume orders
- Negotiable pricing and delivery schedules. Long-term supply agreements available.
Contact us for a free quote with your target OD, wall thickness, length, and quantity.
Chemical Composition
The chemical composition of S43400 / 434 / X6CrMo17-1 varies slightly between standards. The critical distinction is the molybdenum content, which is the defining element that separates 434 from standard 430. Below are the heat analysis limits per applicable specifications.
| Element | ASTM A268 UNS S43400 | EN 10216-5 X6CrMo17-1 (1.4113) | JIS G3463 SUS434 |
|---|---|---|---|
| Carbon (C) | ≤ 0.12 | ≤ 0.08 | ≤ 0.12 |
| Silicon (Si) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Manganese (Mn) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Phosphorus (P) | ≤ 0.040 | ≤ 0.040 | ≤ 0.040 |
| Sulfur (S) | ≤ 0.030 | ≤ 0.015 | ≤ 0.030 |
| Chromium (Cr) | 16.00 – 18.00 | 16.00 – 18.00 | 16.00 – 18.00 |
| Molybdenum (Mo) | 0.75 – 1.25 | 0.90 – 1.40 | 0.75 – 1.25 |
| Nickel (Ni) | — | — | — |
The molybdenum content — typically 0.75–1.40% depending on the governing standard — is the key differentiator from Type 430 (which contains no intentional molybdenum). This addition substantially improves pitting resistance in chloride-containing environments and mildly acidic media.
Manufacturing Process
S43400 seamless tubes at Fushun Steel Tube are produced from fully killed, vacuum-degassed (EAF + LF + VD) billets. For critical-service applications, we offer ESR or PESR upgrade paths that reduce inclusion content and improve microstructural homogeneity. The pipe-making route depends on final dimensions: larger-diameter tubes are hot-pierced on a multi-stand MPM line, while precision and small-bore tubes follow cold-drawing or cold-rolling on Pilger mills. Every S43400 billet undergoes surface conditioning and ultrasonic inspection prior to reheating. Post-forming, tubes are annealed in a controlled-atmosphere furnace to dissolve chromium carbides and restore full corrosion resistance, then straightened, pickled, and passivated before final inspection.
For applications demanding tighter tolerances or smoother internal surfaces, our cold-drawn steel tube and stainless steel tube capabilities can be combined with additional processing. Request a sample to evaluate our S43400 tube quality firsthand.
Mechanical Properties
Mechanical properties of S43400 seamless tubes are strongly influenced by heat treatment condition and final cold work. The values below represent the annealed condition per applicable standards. Higher strength levels can be achieved through controlled cold working for specific applications.
| Property | ASTM A268 S43400 | EN 10216-5 1.4113 | EN 10297-2 1.4113 |
|---|---|---|---|
| Tensile Strength, Rm | ≥ 450 MPa (65 ksi) | 450 – 630 MPa | 450 – 630 MPa |
| Yield Strength, Rp0.2 | ≥ 240 MPa (35 ksi) | ≥ 250 MPa | ≥ 240 MPa |
| Elongation (longitudinal) | ≥ 20% (in 2 in) | ≥ 20% (A5) | ≥ 20% (A5) |
| Hardness | ≤ 89 HRB (≤ 183 HBW) | ≤ 200 HBW | ≤ 200 HBW |
The combination of moderate strength, good ductility, and magnetic response makes S43400 an attractive alternative in designs that would otherwise specify 304L where stress corrosion cracking resistance — rather than general corrosion resistance — is the driving material selection criterion.
Heat Treatment
As a ferritic stainless steel, S43400 is hardened only by cold work and cannot be strengthened through martensitic transformation. The standard heat treatment is full annealing, which dissolves chromium carbides and homogenizes the ferritic microstructure.
| Treatment | Temperature Range | Holding Time | Cooling Method |
|---|---|---|---|
| Full Anneal | 760 – 830 °C (1400 – 1525 °F) | 30–60 min per 25 mm of section thickness | Air cool or water quench |
| Subcritical Anneal | 700 – 760 °C (1290 – 1400 °F) | 1–4 hours | Air cool |
| Stress Relief | 200 – 370 °C (400 – 700 °F) | 30–60 min per 25 mm | Air cool |
Heating should be uniform, and prolonged exposure near the 475 °C embrittlement range must be avoided. For S43400 tubes that will operate for extended periods above 370 °C, consult our engineering team for application-specific heat treatment recommendations.
Surface Finish & Tolerances
S43400 seamless tubes from Fushun Steel Tube are supplied with surface conditions tailored to the end application. Standard finishes include hot-rolled and pickled (mill finish), cold-drawn bright, and cold-rolled polished. Tubes can be further processed by centerless grinding or CNC machining for tight-tolerance applications such as hydraulic cylinder barrels, instrumentation tubing, and mechanical components.
- Hot-rolled & pickled (HRAP)
- Matte gray, clean surface free of scale. Suitable for most industrial and structural applications.
- Cold-drawn bright (CDB)
- Smooth, semi-bright to bright surface. Typical OD tolerance H9–H10, WT tolerance ±10%.
- Cold-rolled polished
- Bright, smooth finish with tight dimensional control. OD tolerance down to H8.
- Bead-blasted / satin
- Uniform matte appearance for architectural and aesthetic applications. Available on request.
Internal surface finishes from as-drawn to honed (RMS 0.4 μm / 16 μin or better) are available for fluid power and instrumentation tubing. For precision hydraulic applications, explore our cold-rolled steel tube capabilities.
Quality Assurance & Testing
Every S43400 seamless tube shipment from Fushun Steel Tube is backed by a complete quality assurance workflow aligned with ISO 9001 requirements. Our testing protocol is designed to confirm dimensional accuracy, mechanical integrity, and corrosion resistance before release.
- Raw material inspection — 100% billet identity verification via handheld OES. Only billets within specification proceed to reheating.
- In-process dimensional checks — OD and WT are measured continuously during hot rolling and at regular intervals during cold drawing.
- Heat treatment verification — Furnace charts are reviewed for every batch. Hardness testing is performed on samples from each heat treatment lot.
- Non-destructive testing — Eddy current or ultrasonic testing per ASTM E213 / E426 / E309 on all finished tubes. Hydrostatic testing per applicable product standard.
- Mechanical testing — Tensile testing (room temperature) per ASTM A370 / EN 10002-1. Flattening and flaring tests per the governing specification.
- Metallographic examination — Grain size, microstructure, and intergranular corrosion susceptibility assessed on sample tubes from each heat.
- Dimensional final inspection — 100% visual and dimensional inspection, including surface roughness measurement where specified.
Certificates to EN 10204 3.1 (standard) or 3.2 (with third-party witness) are provided with every order. Tell us your specifications if your project requires additional testing beyond the standard protocol.
Packing & Shipping
S43400 stainless steel tubes are packed for secure transit to destinations worldwide. Standard export packaging includes:
- Small-diameter tubes (< 2 in OD): Bundled with steel straps, wrapped in water-resistant paper, and packed in seaworthy wooden cases.
- Medium and large-diameter tubes: Individually end-capped with plastic protectors, strapped in hexagonal bundles, and loaded into open-top or flat-rack containers.
- Precision and cold-drawn tubes: Each tube individually sleeved or wrapped in VCI paper to prevent surface damage and atmospheric corrosion during transit.
- Custom packaging: Labeling, barcoding, and customer-specific packing instructions are supported for volume orders.
Shipping from Hunan Province, China, via major ports including Shanghai, Ningbo, and Shenzhen. Standard and expedited freight options are quoted on a per-order basis.
Frequently Asked Questions
- What sizes of S43400 stainless steel seamless tube do you supply?
- We supply S43400 seamless tubes from 6 mm to 610 mm OD with wall thicknesses from 0.5 mm to 50 mm, in lengths up to 18 m. Custom dimensions are available on request with a minimum order of 2–3 tons.
- What is the difference between 434 and 304 stainless steel?
- 434 is a ferritic stainless steel with molybdenum, offering better pitting and crevice corrosion resistance than 430. Unlike 304 (austenitic), 434 contains little to no nickel, is magnetic, and provides superior stress corrosion cracking resistance in chloride environments at a lower material cost.
- What standards cover 434 stainless steel seamless tubes?
- S43400 seamless tubes are supplied under ASTM A268/A268M, EN 10216-5, and EN 10297-2. We provide EN 10204 3.1 or 3.2 certificates with every shipment upon request.
- What is the typical delivery time for X6CrMo17-1 seamless tube orders?
- Ready-stock items ship within approximately 7 days. Custom-sized 1.4113 seamless tubes typically deliver in 25–35 days with a 2–3 ton MOQ. Small trial orders are accepted for special-grade tubes.
- Can 434 stainless steel tubes be used in elevated temperature applications?
- 434 stainless steel performs well in intermittent service up to 870 °C and continuous service up to 815 °C in oxidizing atmospheres. For prolonged elevated-temperature use, we recommend consulting our engineering team for application-specific guidance.
Have a question not covered here? Tell us your specifications and our engineering team will respond within one business day.
Request a Quote
Fushun Steel Tube delivers S43400 / 434 / X6CrMo17-1 / SUS434 stainless steel seamless tubes with full traceability and ISO 9001 quality assurance. Whether you need standard stock sizes or custom-manufactured tubes to your exact print, contact us for a free quote with your target dimensions, quantity, applicable standard, and delivery schedule. Small trial lots and volume orders are both welcome.
