Austenitic stainless steel names often combine a familiar ASTM grade with an EN number and a UNS identifier. Those labels help identify a family, but they do not prove that every supplier product has identical chemistry. The table below selects rows from Outokumpu’s Core range datasheet and preserves the product name alongside its EN, ASTM, and UNS designations. Its chemistry values are described by the producer as typical composition by mass. They are not specification limits and should not be used as acceptance criteria for a delivered heat.

Austenitic Stainless Steel Composition and Grades

Compare 304 and 304L carefully

In the cited Core data, the 304/4301 row reports typical carbon at 0.04% and chromium/nickel at 18.1% and 8.1%. The 304L/4307 product row reports a lower typical carbon value of 0.02%, with the same listed chromium and nickel values. Outokumpu describes its 304L product as a low-carbon alternative; reduced carbon helps limit carbide precipitation after heat input, such as welding. This comparison is specific to the producer’s grade range and does not replace the applicable chemistry table in the governing specification.

The same family can have useful variants

304LN adds nitrogen in the cited product range and is described as a higher-strength, low-temperature-toughness option. Grade 321 uses titanium stabilization; the datasheet lists titanium under “Others” and explains its use at elevated temperatures. These distinctions explain why a short grade name alone is not enough for selection. Identify the exact product, standard designation, form, heat treatment, and service environment. The table keeps nitrogen text from the source where it is reported and avoids inventing a numeric value for a dash.

Worked designation check

Suppose a drawing calls for UNS S30403 and EN 1.4307. Those identifiers correspond to Outokumpu Core 304L/4307 in this datasheet, whose typical listed chemistry includes 0.02% carbon, 18.1% chromium, and 8.1% nickel. The cross-reference supports a designation lookup only. Before approving stock, compare the purchase order’s exact ASTM/EN requirements with the mill test certificate and verify the product form and condition. Two matching aliases on a supplier page do not constitute a heat-level chemical analysis.

What chemistry does not determine

Composition can help distinguish alloy families, but it does not alone determine corrosion resistance in every environment. Chloride concentration, temperature, crevices, surface condition, fabrication, and stress can alter performance. Chemistry also does not establish yield strength, hardness, sensitization, or a qualified weld procedure. The Outokumpu datasheet provides separate information for applications and mechanical properties; use the section appropriate to the question. Do not infer that a grade with more chromium or nickel is universally better without considering the specific service conditions.

Common mistakes and source

Avoid treating a typical chemistry value as a maximum permitted by ASTM or EN. Do not combine values from separate manufacturer datasheets into one supposed grade limit, and do not assume two 304L products with different EN numbers are interchangeable in every respect. This article’s rows are a narrow product-range snapshot from the linked Outokumpu datasheet, which explicitly identifies the table as typical chemical composition by mass. Use the controlling material specification and certified analysis for acceptance, and ask the supplier when a designation or product form is ambiguous. For a purchase, match the product form and thickness range as well as the grade code. A sheet product and a bar product may have different applicable requirements, delivery conditions, and certification records. Chemistry is one part of a material specification, not a substitute for checking the remaining clauses.

References

• Outokumpu Core range datasheet, Table 1: Chemical composition

This reference is limited to the conditions named in the data and sources. Confirm the governing specification, complete geometry, material, operating environment, and service loads before using any value for design, procurement, inspection, or safety-critical decisions.