Stainless Steel 303
UNS S30300 · Austenitic · Product-specific technical reference.
Stainless Steel 303 (S30300) is included here as a material reference. Sulphur improves machining and can reduce corrosion performance and weldability relative to low-sulphur grades.
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-276, Table 1 (bar/shape reference). Values are mass %. This selected-element table does not replace the complete source table and footnotes.
| Element | Requirement, mass % |
|---|---|
| C | ≤0.15 |
| Mn | ≤2.00 |
| P | ≤0.20 |
| S | 0.15 min |
| Si | ≤1.00 |
| Cr | 17.0-19.0 |
| Ni | 8.0-10.0 |
| Mo | ≤0.60 |
Check required minor/combined elements, heat/product-analysis rules and footnotes in the ordered edition. An element not listed here does not imply zero content or absence of a standard requirement.
2. Mechanical Requirements and Delivery Condition
No single tensile/yield/elongation set is asserted as an alloy-wide minimum. Specify product standard, size, manufacturing route, heat treatment/ageing and test direction before selecting acceptance values. “NON-TUBULAR REFERENCE” identifies a reference scope, not a delivery or heat-treatment condition.
3. Designation References
UNS S30300 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 |
|---|---|---|---|---|
| S30300 | 1.4305 | X10CrNiS18-9 | SUS303 | — |
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
Sulphur improves machining and can reduce corrosion performance and weldability relative to low-sulphur grades.
Austenitic grades can suffer chloride SCC, local corrosion or sensitisation under suitable conditions. Low carbon/stabilisation reduces particular risks without eliminating every thermal-history effect. Compare suitable high-alloy austenitic, duplex and nickel candidates using representative service data.
5. Product Standards and Ordering Basis
This entry is primarily a related-material reference. Confirm the actual product form and applicable standard before ordering. Bar, forging and flat-product specifications do not automatically cover seamless pipe/tube.
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
Machined bar parts; not an automatic welded pressure-pipe material.
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.