Type 304L stainless steel

Identity and ordering basis

Outokumpu lists 220 MPa 0.2% proof strength for cold-rolled Core 304L/4307 coil and sheet at 20°C under EN 10088-2, versus 200 MPa for hot-rolled coil and sheet or quarto plate. The quarto plate row also has a different tensile range. Select the row by ordered form. Outokumpu Core table 5

Type 304L is a low-carbon austenitic chromium-nickel stainless steel identified as UNS S30403. Outokumpu lists both Core 304L/4307 (EN 1.4307) and Core 304L/4306 (EN 1.4306). A shared 304L name does not establish that every EN designation, product specification and producer offering is interchangeable. Outokumpu Core range data sheet

Alleima's 3R12 seamless tube/pipe product lists TP304L/TP304 and S30403/S30400, with carbon ≤0.030% in its nominal-composition table. Confirm any required dual certification from the certificate for the actual heat. Alleima 3R12 identity and composition

Form-specific mechanical values

Outokumpu's Core 304L/4307 table gives these 20°C values according to EN 10088-2, with product forms explicitly separated. Confirm the governing specification's dimensional range, sampling and acceptance requirements before applying a row to an order. Outokumpu mechanical properties, Table 5

The A gauge length is 5.65√S0. These entries are not generic cold-worked-bar properties or allowable design stresses. Keep 0.2% and 1.0% proof strength separate; tensile strength is a different quantity. Outokumpu table notes

Match the actual ordered form, condition, temperature and test direction to the applicable record. Do not use the upper tensile bound as a minimum strength or infer fatigue life, impact performance or pressure capacity from a room-temperature tensile entry.

For a substitution, reassess section properties, stability, stiffness, connections and load history together. A nominally matching alloy or higher measured strength does not establish equivalent finished-part behavior.

Physical-property calculation

Outokumpu lists density 7.9 kg/dm³ and Young's modulus 200 GPa at 20°C for Core 304L/4307. Outokumpu physical properties, Table 7

Calculated illustration: a solid 100 × 100 × 5 mm blank occupies 0.05 dm³. At the listed density, estimated mass is 0.395 kg. This assumes nominal solid dimensions and excludes tolerances, holes, finish and hardware. Use finished geometry and an appropriate delivered-material input for the final mass model.

The modulus figure is not a guarantee of a fabricated assembly's stiffness. Geometry, support, joints and temperature still matter. Keep elastic deflection calculations separate from strength checks and from permanent deformation caused during fabrication.

Low carbon and corrosion limitations

Alleima's 3R12 discussion relates low carbon to resistance against intergranular attack following welding or heating. That benefit does not make the alloy immune to every corrosion mechanism. Alleima intergranular-corrosion discussion

The same source warns of pitting and crevice corrosion even at relatively low chloride content, and stress-corrosion cracking involving tensile stress and certain solutions, particularly chlorides, above roughly 60°C. It also calls attention to corrosive shutdown condensates. These are product-selection warnings, not a universal safe chloride concentration or temperature threshold. Alleima localized-corrosion and SCC sections

Document concentration, temperature, contaminants, aeration, deposits, crevices and sustained stress for the actual duty. Include cleaning, startup, shutdown and upset conditions. An exposed coupon's result does not settle the behavior of a gasket interface or deposit-covered surface.

Set acceptable general-corrosion and localized-attack criteria before selecting evidence. Obtain exposure-specific advice or representative tests where published data do not match the application. A material's use in food, chemical or architectural equipment does not establish compliance or life for an individual component.

Welding and fabrication controls

For 3R12, Alleima recommends welding without preheat, normally without subsequent heat treatment, with heat input <2.0 kJ/mm, interpass temperature <150°C, and ER308L among its recommended GTAW/GMAW fillers. These are producer recommendations, not a qualified procedure for every S30403 joint. Alleima welding guidance

Resolve joint preparation, base-material combination, filler, shielding, heat input, temperature measurement, sequence and inspection through the approved procedure. Review dissimilar-metal joints and repairs separately. Low-carbon parent material alone does not establish the weld's chemistry, soundness or corrosion performance.

Plan forming and machining around the supplied condition and required final geometry. Qualify tooling, springback, allowances and cutting parameters on representative stock. If a proposed route adds heating, stress relief or other treatment, establish its purpose and acceptance rather than borrowing a cycle from another steel.

Specify required surface preparation after thermal processing and finishing. Keep dimensions, appearance and corrosion requirements explicit; a bright surface does not prove the absence of contamination or establish suitability in a crevice. Obtain the actual product's handling information and the facility procedure for the operation.

Finished-part release and source versions

A release record should connect specification, producer, grade, heat/lot, condition and certificate to the drawing, fabrication history and final inspection. Add pressure/leak, fatigue, dimensional or corrosion acceptance where the component requires it. Resolve substitutions before production rather than accepting a similar trade name or one favorable property result.

The Outokumpu PDF prints 1560EN:4, November 2022, verified directly; later URL modification timestamps are not treated as new editions. Alleima's cited tube/pipe sheet is dated 9 May 2025. These source identities do not establish the latest contractual standard editions. Review date: 2026-11-01, America/Los_Angeles.

See grades, tempers and conditions.