Bar and Rod
Plate and Sheet
Strip
Pipe and Tube
Wire
Welding
Powder Material
Cast Products
Forged Products
Fittings
Fastening
Round Bar:
φ2–500 mm, 1–6 m length
Flat/Square Bar:
4–100 mm thickness/width
Hex Bar:
A/F 3–100 mm
Hollow Bar:
OD 20–300 mm
Sheet:
0.3–6 mm thickness
Medium Plate:
6–25 mm thickness
Heavy Plate:
25–100 mm thickness
Standard Strip:
0.05–3 mm thick,
10–600 mm wide
Precision strip:
0.01–0.5 mm thick,
tight tolerance ±0.005 mm
Foil:
0.005–0.1 mm thick
Seamless Tube:
OD 6–450 mm,
WT 1–50 mm,
1–12 m length
Welded Tube:
OD 10–600 mm,
WT 1–20 mm
Capillary Tube:
OD 1–10 mm,
WT 0.1–2 mm
Wire Form:
Cold Drawn Wire,
Bright Wire,
Spring Wire,
Fine Wire,
Ultra-fine Wire
General Diameter:
φ0.1–10 mm
Coil Weight:
50–500 kg,
customizable tolerance
Solid Wire:
φ0.8–4.0 mm
Flux-cored Wire:
φ1.2–4.0 mm
Welding Rod:
φ2.0–5.0 mm
Powder Form:
AM 3D Printing Powder,
Spherical Powder,
Gas-atomized Powder,
Water-atomized Powder
Particle Size:
10–150 μm
Sphericity:
≥90% for AM grade
Cast Ingot:
φ200–800 mm
Precision Casting:
min wall 0.5 mm
Cast Pipe:
OD 100–600 mm,
WT 10–50 mm
Forged Bar:
Φ35–500 mm
Forged Ring:
OD 200–2000 mm
Forging Weight:
1–5000 kg
Fittings Form:
Elbow, Tee, Reducer, Flange, Cap, Outlet, Lap Joint
Size range:
1/2''–24'' (DN15–DN600)
Wall thickness:
Sch10–Sch160, STD, XS, XXS
Pressure Class:
150–2500 LB
Fastening Form:
Bolt, Nut, Screw, Stud, Washer, Pin, Rivet
Metric: M3–M64
Imperial: #4–2.5''
Length: 6–500 mm
S44400 is a molybdenum-alloyed, dual-stabilized (titanium and niobium) ferritic stainless steel containing about 18% chromium and 2% molybdenum, with no deliberate nickel. This datasheet presents the material within the American (ASTM / ASME / UNS) standard system.
With nominally 18% chromium and 2% molybdenum and ultra-low carbon and nitrogen, 444 provides corrosion resistance approaching that of type 316 — including pitting and crevice-corrosion resistance — while, as a ferritic grade, being essentially immune to chloride stress-corrosion cracking. The titanium and niobium stabilization ties up carbon and nitrogen, so the steel can be welded in all dimensions without sensitisation or post-weld annealing. Being nickel-free it is magnetic, cannot be hardened by heat treatment, has good cold formability, and offers good high-temperature oxidation resistance to about 1000 °C.
Typical applications include hot-water tanks and solar water heaters, automotive exhaust systems, heat exchangers, brewing and food-processing equipment, electric kettles, and outdoor panels.
Typical values, annealed condition.
| Property | Value | Unit |
|---|---|---|
| Density | 7.7 | g/cm³ |
| Melting range | 1480–1530 | °C |
| Elastic modulus | 220 | GPa |
| Coefficient of thermal expansion (20–100 °C) | 10.4 | µm/m·°C |
| Thermal conductivity (100 °C) | 26.8 | W/m·K |
| Specific heat (20 °C) | 460 | J/kg·K |
| Structure | Ferritic | — |
Specified per ASTM A240 (UNS S44400).
| Element | Symbol | Min % | Max % | Role in Alloy |
|---|---|---|---|---|
| Iron | Fe | Balance | — | Base element |
| Chromium | Cr | 17.5 | 19.5 | Corrosion / oxidation resistance |
| Molybdenum | Mo | 1.75 | 2.50 | Pitting / crevice corrosion resistance |
| Titanium + Niobium | Ti+Nb | 0.20 + 4×(C+N) | 0.80 | Dual stabiliser; ties up C and N |
| Nickel | Ni | — | 1.00 | Residual |
| Manganese | Mn | — | 1.00 | Deoxidiser |
| Silicon | Si | — | 1.00 | Deoxidiser |
| Carbon | C | — | 0.025 | Ultra-low (weldability) |
| Nitrogen | N | — | 0.035 | Ultra-low (stabilised) |
| Phosphorus | P | — | 0.040 | Residual impurity |
| Sulphur | S | — | 0.030 | Residual impurity |
Nominal: 18Cr-2Mo dual-stabilized (Ti + Nb) ultra-low-carbon ferritic stainless steel.
Annealed condition, per ASTM A240 for UNS S44400.
| Condition | Property | Value |
|---|---|---|
| Annealed | Tensile strength (UTS) | ≥415 MPa |
| Annealed | 0.2% yield strength | ≥275 MPa |
| Annealed | Elongation at break | ≥20 % |
| Annealed | Hardness | ≤217 HB (~96 HRB) |
| — | Elastic modulus | 220 GPa |
Confirm against the mill test report.
| Environment | Performance | Notes |
|---|---|---|
| Atmospheric / general | Excellent | Approaches type 316 |
| Chloride pitting / crevice | Very Good | 2% Mo; similar to 316 |
| Chloride stress-corrosion cracking | Excellent | Ferritic — essentially immune (advantage over 316) |
| Mild acids / potable & hot water | Very Good | Common tank / heater application |
| Oxidation (elevated temperature) | Very Good | Useful to ~1000 °C |
The 2% molybdenum gives pitting and crevice resistance similar to 316, while the ferritic structure provides essentially complete immunity to chloride stress-corrosion cracking — a key advantage over austenitic 304/316.
A ferritic grade; cannot be hardened by heat treatment. Properties are set by annealing.
Anneal Heat to approximately 850–950 °C and air cool. Owing to dual stabilization, post-weld annealing is not required to restore intergranular corrosion resistance. Avoid prolonged exposure near 475 °C (embrittlement).
Excellent weldability without sensitisation owing to titanium/niobium stabilization; can be welded in all dimensions without post-weld annealing. Note low toughness at the ductile-to-brittle transition in heavier sections.
| Welding Process | Applicability | Filler / Consumable |
|---|---|---|
| GTAW / TIG | Very Good | AWS A5.9 ER430LNb / stabilized ferritic, or Ni-base |
| GMAW / MIG | Good | Stabilized ferritic filler |
| Resistance / seam | Very Good | — |
Use a stabilized stainless or nickel-base filler to maintain weld-metal corrosion resistance. No post-weld anneal required.
Machining Guidelines
| Parameter | Recommendation |
|---|---|
| Machinability | Good; similar to other ferritic grades |
| Work hardening | Low rate — does not harden excessively |
| Coolant | Ample flood coolant |
Forming Processes
| Process | Notes |
|---|---|
| Cold forming | Good — roll forming, mild stretch bending, drawing |
| Hot forming | ~1100–800 °C; anneal afterward |
| Industry | Typical Components | Key Requirements |
|---|---|---|
| Water heating | Hot-water tanks, solar water heaters, kettles | SCC immunity + corrosion resistance |
| Automotive | Exhaust systems, trim | Corrosion + oxidation resistance |
| Food / brewing | Brewing and processing equipment | Corrosion resistance + hygiene |
| Heat transfer | Heat exchangers, condensers | Chloride resistance + thermal conductivity |
| Product Form | ASTM Standard | ASME Code |
|---|---|---|
| Plate, sheet and strip | ASTM A240 | ASME SA-240 |
| Seamless / welded tube | ASTM A268 | ASME SA-268 |
| Bar and shapes | ASTM A479 | — |
| Welding consumables | AWS A5.9 ER430LNb | — |
Molybdenum-alloyed, dual-stabilized ferritic stainless steel. UNS S44400.
| UNS | Cr % | Mo % | Stabiliser | Best Used For |
|---|---|---|---|---|
| S44400 | 17.5–19.5 | 1.75–2.5 | Ti + Nb | 18Cr-2Mo ferritic; 316-like corrosion, SCC immunity |
| S43940 | 17.5–18.5 | — | Nb + Ti | 18Cr dual-stabilized; hot exhaust |
| S43035 | 17–19 | — | Ti | 18Cr-Ti ferritic; cold-end exhaust |
| S43000 | 16–18 | — | — | General ferritic; non-stabilized |
| S31603 | 16–18 | 2–3 | — | Austenitic Mo grade (316L, non-magnetic) |
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