Stainless Steel 444
UNS S44400 · Mo-alloyed ferritic · Product-specific technical reference.
Stainless Steel 444 (S44400) is included here as a material reference. Molybdenum assists local-corrosion resistance in selected water duties; not universally equivalent to 316.
Scope: Numerical limits below apply only to the named source, product form and condition. They are not measured results, design allowable stresses or guarantees for every product with this UNS. Acceptance follows the purchase order and applicable design/product standards.
1. Selected Chemical Requirements
Basis: ASME BPVC II.A-2023, SA-268/SA-268M, Table 1 (tubing reference). Values are mass %. This selected-element table does not replace the complete source table and footnotes.
| Element | Requirement, mass % |
|---|---|
| C | ≤0.025 |
| Mn | ≤1.00 |
| P | ≤0.040 |
| S | ≤0.030 |
| Si | ≤1.00 |
| Cr | 17.5-19.5 |
| Mo | 1.75-2.50 |
| N | ≤0.035 |
Check the full Ti/Nb and C+N stabilisation requirement in the named tube specification. These selected elements are not a complete procurement table.
2. Mechanical Requirements and Delivery Condition
Basis: ASTM A213/A213M-25, Table 4. Published room-temperature minima. The source MPa and ksi values are shown separately; do not combine unit systems when assessing an order.
| Product / condition / size | Tensile, MPa (ksi) | 0.2% proof / yield, MPa (ksi) | Elongation, % |
|---|---|---|---|
| Annealed | ≥ 415 (60) | ≥ 275 (40) | ≥ 20 |
Seamless boiler/heat-exchanger tube requirements only. Elongation depends on specimen geometry and table notes. Pipe and transverse values require separate checks.
3. Designation References
UNS S44400 is the material identifier used here. Cross-system names below are comparison candidates only. EN, JIS and GB/T grades can differ in chemistry, form, condition and testing; substitution requires a technical comparison and project-required approval.
| UNS | EN / DIN | EN name | JIS | GB / ISC |
|---|---|---|---|---|
| S44400 | 1.4521 | X2CrMoTi18-2 | SUS444 | 019Cr19Mo2NbTi / 00Cr18Mo2 |
These are recorded designation references, not a certification of equivalence. A dash means no confirmed entry is supplied. A common UNS number or commercial name does not establish branded origin.
4. Fabrication and Service Considerations
Molybdenum assists local-corrosion resistance in selected water duties; not universally equivalent to 316.
Ferritic, martensitic and precipitation-hardening grades have different magnetic, heat-treatment, welding and toughness behaviour from austenitic steels. Do not infer cryogenic toughness or freedom from embrittlement from a generic stainless-steel description. Apply the specified welding and heat-treatment route.
5. Product Standards and Ordering Basis
A213/A213M covers specified seamless boiler/superheater/heat-exchanger tube; A312/A312M is a pipe specification and A269/A269M is for specified general-service tubing. Confirm that the ordered edition actually covers the UNS, route, size and condition. Alternative EN/GB/JIS delivery requires separate verification.
State grade/UNS, form, route, specification/edition, OD/wall/length, condition, examination and documents. ASME SA/SB acceptance and design-code permission require separate checks. EN 10204 type 3.1 is an inspection document, not independent product approval. Chemical and mechanical tests can use different heat/lot sampling bases.
6. Typical Applications
Qualified water and heat-exchanger components.
These are examples, not a service-envelope approval. Confirm medium, concentration, temperature, pressure, flow/stagnation, deposits, crevices, stress and fabrication condition.
7. Product Enquiries and Related Pages
Forms, sizes, availability and certification are confirmed in the written quotation. Send an enquiry with the actual specification and service requirements.
Reference review: 30 October 2026. Editions identify the sources used; they do not assert that all named editions remain active or that alternative standards have identical requirements.