# Outokumpu Core 304/4301

Producer-specific identification, form-dependent properties and fabrication limits for Core 304/4301.

Reviewed: 2026-11-01

Tags: materials, stainless-steel, producer-products

## Product identity and ordering

Outokumpu's **EN 10088-2 Core 304/4301** table gives **230 MPa 0.2% proof strength** at **20°C** for **cold-rolled coil and sheet** and **210 MPa** for **hot-rolled coil and sheet or quarto plate**. Select by ordered form. The table reports 1.0% proof strength separately. [Outokumpu Core Table 5](https://www.outokumpu.com/-/media/files/products/core/outokumpu-core-range-datasheet.pdf?modified=20251117111909&revision=025e9931-a1d5-4c8f-8ff5-f881d38916da)

**Core 304/4301** is Outokumpu's designation for an austenitic stainless steel associated with **EN 1.4301, ASTM Type 304 and UNS S30400**. Its quarto-plate program lists a **typical composition by mass** of 0.04% carbon, 18.1% chromium and 8.1% nickel. These are producer typical values, not the full chemical limits of every referenced specification or the measured analysis of a delivered heat. [Outokumpu: quarto-plate product and dimension program](https://otke-cdn.outokumpu.com/-/media/files/products/flat-products/outokumpu-quarto-plate-product-and-dimension-program-1-2024-us-version-with-imperial-units.pdf?modified=20240117072854&revision=9811fa00-df7a-4f88-8194-5f01aeb6610a)

Outokumpu identifies **Core 304L/4307** as a separate low-carbon alternative with improved resistance to intergranular corrosion after heat input. Review the specified composition and service before substitution. [Outokumpu: Core range datasheet](https://www.outokumpu.com/-/media/files/products/core/outokumpu-core-range-datasheet.pdf?modified=20251117111909&revision=025e9931-a1d5-4c8f-8ff5-f881d38916da)

## Mechanical data depend on form and specification

The cited Core datasheet is printed **1560EN:4, November 2022**; the download URL's modification timestamp does not change that printed edition. Table 5 gives the following Core 304/4301 values at **20 °C**, according to **EN 10088-2**:

| Product form | Rp0.2 proof strength | Rp1.0 proof strength | Rm tensile strength |
| --- | ---: | ---: | ---: |
| Cold-rolled coil/sheet, C | 230 MPa | 260 MPa | 540–750 MPa |
| Hot-rolled coil/sheet, H | 210 MPa | 250 MPa | 520–720 MPa |
| Quarto plate, P | 210 MPa | 250 MPa | 520–720 MPa |

Source: [Outokumpu Core datasheet, Table 5 and form legend](https://www.outokumpu.com/-/media/files/products/core/outokumpu-core-range-datasheet.pdf?modified=20251117111909&revision=025e9931-a1d5-4c8f-8ff5-f881d38916da).

## Cold work, forming and magnetic response

Outokumpu's stainless-family guidance describes austenitic steels as nonmagnetic in the solution-annealed condition, while cold working can increase strength and produce magnetic martensite in some grades. A magnet response after forming is therefore insufficient by itself to identify or reject a material. Where magnetic permeability matters, define and test that requirement in the finished condition rather than relying on a family label. [Outokumpu: stainless steel family](https://www.outokumpu.com/en/expertise/2020/the-stainless-steel-family)

For bending and roll bending, Outokumpu emphasizes springback and the need for adjustments when grade or thickness changes. For deep drawing and stretching, tool condition and lubrication influence surface quality. Its forming guidance also warns that severely cold-worked regions have reduced capacity for subsequent operations such as hole flanging. [Outokumpu: forming guidance](https://www.outokumpu.com/en/expertise/stainless-basics/forming)

Qualify bend radii, rolling direction, edge condition, forming sequence and surface protection on representative material. A tensile elongation value does not guarantee a particular drawn shape or hole expansion. Retain the distinction between incoming sheet properties and locally work-hardened regions in the fabricated component.

## Welding and the finished joint

Outokumpu explains that weld microstructure depends on composition and thermal history, including cooling rate. Its guidance calls for a welding-procedure qualification when introducing a new material or process and evaluates strength, ductility and corrosion performance of the welded construction together. This is more specific than simply classifying a base grade as weldable. [Outokumpu: welding guidance](https://www.outokumpu.com/en/expertise/stainless-basics/welding)

For Core 304/4301 fabrication, define the actual joint, thickness, welding process, filler requirements, shielding, heat control and acceptance criteria through the applicable procedure. Assess distortion and service exposure, and retain traceability of any substituted base or filler metal. The product designation alone supplies no universal heat-input setting, filler selection or post-weld heat-treatment instruction.

Outokumpu's post-fabrication guidance identifies removal of weld oxides, spatter and contamination as important to restoring surface and corrosion performance. It explains that pickling removes material and therefore needs careful control. Specify the required surface outcome and a suitable qualified cleaning process, including access to internal surfaces; a shiny cosmetic finish is not proof that contamination or heat-affected surface layers have been removed. [Outokumpu: post-fabrication treatment](https://www.outokumpu.com/en/expertise/stainless-basics/post-fabrication-treatment)

## Corrosion and service selection

“Stainless” does not mean corrosion-proof. Outokumpu's atmospheric-corrosion article discusses chloride deposition from sea spray and de-icing salts, sheltered areas with limited rain washing, surface roughness and maintenance as interacting selection factors. It lists Core 304/4301 among options for interior and light urban conditions, while more severe environments require a different assessment. [Outokumpu: atmospheric corrosion guidance](https://www.outokumpu.com/en/expertise/2025/stainless-steel-and-atmospheric-corrosion-what-you-need-to-know)

Do not treat an architectural exposure recommendation as qualification for chemical immersion, a hot cleaning solution or a creviced process assembly. For a proposed tank, food-equipment part or outdoor panel, state the actual fluids, concentrations, temperature, contaminants, wet/dry cycle, surface finish and cleaning access. Review welded and creviced details as well as the flat parent metal. Resolve appearance requirements separately from loss-of-integrity criteria: staining can fail an architectural requirement before a structural limit is reached.

Use the governing design rules and verified properties for the specified form, condition and temperature.

## Useful purchase and acceptance record

A complete record should retain:

- Exact producer product name and required designation/specification, including edition.
- Form, thickness, dimensions, delivery condition and finish.
- Required certificate, heat analysis, mechanical results and traceability.
- Forming, welding and surface-restoration procedures and inspections.
- Actual exposure and design-code requirements, including cleaning cycles.
- Finished-part dimensional, surface, joint and corrosion-related acceptance criteria.

The Core PDF's printed edition is identified above. Undated manufacturer guidance and year-organized article URLs are supporting technical context, not evidence of a revised material specification. Check current order-specific documentation before procurement or substitution.

## Related reference

[Grades, conditions and material selection](../grades-tempers-and-conditions.md)