441 Stainless Steel (UNS S43940)
Ferritic (dual-stabilized) · EN 10088-2, ASTM A240/A240M · Density 7.7 g/cm³
Type 441 (EN 1.4509, UNS S43940) is an 18% chromium ferritic stainless steel stabilized with both titanium and niobium. Dual stabilization keeps welds corrosion-resistant and preserves strength at exhaust temperatures up to roughly 950 °C peak, which has made 441 the mainstream European grade for exhaust hot ends and welded decorative tube.
Chemical Composition (wt%)
| C | Mn | Si | Cr | Ti | Nb | P | S |
|---|---|---|---|---|---|---|---|
| ≤0.030 | ≤1.00 | ≤1.00 | 17.5–18.5 | 0.10–0.60 | 3×C+0.30–1.00 | ≤0.040 | ≤0.015 |
Single values are maximums unless a range is shown. Balance: Fe. Per EN 10088-2, ASTM A240/A240M.
Mechanical Properties
| Yield strength Rp0.2 | ≥230 MPa |
|---|---|
| Tensile strength Rm | 430–630 MPa |
| Elongation A80 | ≥18% |
| Basis | EN 10088-2, cold-rolled |
Room-temperature minimum values are summarized for annealed flat product under EN 10088-2, ASTM A240/A240M unless a condition is named in the property label; product form and thickness can change the requirement.
Physical Properties & Structure
| Density | 7.7 g/cm³ |
|---|---|
| Magnetic response | Magnetic because the room-temperature matrix is ferritic. |
| Microstructure | Ferritic (dual-stabilized) |
Corrosion Resistance & Limits
- Ferritic grades resist chloride stress-corrosion cracking better than common austenitic grades, while pitting resistance still depends on chromium, molybdenum and exposure.
- Weld condition, section thickness, crevices, deposits and surface contamination can control service performance; validate the actual fabrication and environment.
Fabrication & Heat Treatment
| Welding | Control heat input, interpass temperature and joint design to limit grain growth and loss of toughness; stabilized grades improve but do not remove these controls. |
|---|---|
| Forming | Formability is useful in sheet gauges but lower than common austenitic grades, especially in heavy sections and severe draws. |
| Machining | Machining is generally straightforward with rigid tooling; avoid smearing, overheating and iron contamination of finished surfaces. |
| Heat treatment | Ferritic grades are not hardened by heat treatment. Annealing can restore ductility, but the temperature and cooling route must follow the product specification. |
Equivalent Grades
The closest international equivalents of 441 Stainless Steel are 1.4509 (X2CrTiNb18) in the EN system, 022Cr18NbTi in the GB system.
These are common corresponding designations, not unconditional substitutes. Verify chemistry, mechanical properties, product standard, delivery condition, dimensions and project approval before changing designation.
| System | Designation |
|---|---|
| UNS | S43940 |
| EN | 1.4509 (X2CrTiNb18) |
| GB | 022Cr18NbTi |
Reference Product Forms & Dimensional Ranges
Common reference product forms for 441 stainless steel: Coil / Strip, Sheet / Plate, Pipe / Tube.
| Finishes | 2B, 2D, bright annealed |
|---|---|
| Sheet / coil thickness | 0.4–3.0 mm |
| Common widths | 1000 / 1250 mm |
Common surface and delivery options: No.1, 2B, BA or mechanically polished finish when supported by the product route; Annealed and pickled, descaled or polished tube finish as specified.
These published ranges are engineering references, not a live-stock or production-capability promise. Confirm the required product form, dimensions, condition, finish and supply route in the quotation.
Typical Applications
- Exhaust manifolds and hot-end pipes
- Welded ornamental and structural tube
- Heat exchanger plates
- Solid-oxide fuel cell interconnects
- Outdoor cladding with nickel-free budget
Frequently Asked Questions
Why is 441 stabilized with both titanium and niobium?
Titanium scavenges carbon and nitrogen in the melt, while niobium adds high-temperature strength and keeps grain size fine in weld zones. Together they let 441 be welded freely and hold shape in thermal cycling — the exact duty profile of an exhaust hot end.
441 vs 409L — when to upgrade?
409L (11% Cr) handles cold-end exhaust parts around 700 °C. 441's 18% chromium and dual stabilization extend oxidation resistance toward 900–950 °C peaks and keep cosmetic appearance longer, so manifolds, front pipes and visible tips step up to 441.
Is 441 a substitute for 304 in appearance parts?
Visually yes — 441 polishes and brushes like 304 and contains even more chromium. Differences show in fabrication: ferritic 441 deep-draws less and its welds need matching stabilized filler. Its nickel-free chemistry keeps pricing more stable than 304.
Organizational author: Tsingshan (Shandong) Iron & Steel Co., Ltd..Review method, status and limitations.
Other stainless steel grades:
304304L316316L201321310S4104302205202301309S316Ti347904L409L4204394442507303317L254 SMO440C17-4 PH2304
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