# Type 301 stainless steel

UNS S30100 austenitic stainless: cold-worked tempers, property interpretation, forming and thermal-history limits.

Reviewed: 2026-11-01

Tags: materials, stainless-steel, cold-worked

## Identity and specification

Cleveland-Cliffs' May 2021 Type 301 bulletin lists **1,276 MPa tensile and 965 MPa yield** in its **full-hard minimum columns**. The footnote says standard practice is to produce to one specified minimum, tensile strength, yield strength or hardness. A simultaneous requirement needs explicit agreement. [Cleveland-Cliffs tables and footnote](https://d1io3yog0oux5.cloudfront.net/_6311866605bd18dd9ea6c0581df61600/clevelandcliffs/db/1190/10509/file/CLF_ProductData_301SS_052021.pdf#page=1)

Type 301, UNS S30100, is an austenitic chromium-nickel stainless steel. ATI's product page lists chromium 16–18%, nickel 6–8% and carbon at most 0.15% by mass, and associates its plate, sheet and strip with ASTM A240, ASTM A666 and ASME SA-240. These listings identify product families; a purchase still needs the applicable standard edition, dimensions, condition and inspection requirements. [ATI, 301 product page](https://www.atimaterials.com/products/Pages/ati-301.aspx)

Do not treat 301LN as another spelling. Outokumpu identifies its Core 301LN/4318 as a low-carbon, nitrogen-alloyed alternative with UNS S30153 and EN 1.4318. Its chemistry and strengthening balance differ from S30100. The existence of an alternative grade does not establish interchangeable forming, welding or service performance. [Outokumpu, Core range, 301LN/4318 entry](https://www.outokumpu.com/en/products/product-ranges/core)

## Why cold-worked condition matters

Cleveland-Cliffs identifies cold working as the route to high strength; Type 301 is not hardenable by heat treatment. Annealed material is essentially nonmagnetic, whereas cold working increases its magnetic response. [Cleveland-Cliffs, *301 Stainless Steel*, May 2021](https://d1io3yog0oux5.cloudfront.net/_6311866605bd18dd9ea6c0581df61600/clevelandcliffs/db/1190/10509/file/CLF_ProductData_301SS_052021.pdf#page=1)

ATI explains that cold rolling promotes martensite formation; the amount depends on rolling reduction, rolling temperature and composition. Consequently, a magnet test cannot establish exact grade, temper or certified strength. ATI also reports longitudinal/transverse differences, especially in compression. [ATI technical data sheet, version 1, February 17, 2014](https://www.atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_301_tds_en_v1.pdf#page=1)

Temper names such as quarter-hard and full-hard are ordering categories, not fractions of an absolute hardness scale. Ulbrinox's technical explanation connects these categories to ASTM A666 mechanical-property requirements and distinguishes them from a generic percentage of cold reduction. Confirm the actual required property combination with the supplier. [Ulbrinox, fundamentals of stainless temper conditions](https://www.ulbrinox.com.mx/en/blog/fundamentos-de-las-condiciones-de-templado-del-acero-inoxidable)

## Bounded strength example

Cleveland-Cliffs' May 2021 bulletin separates its **typical room-temperature annealed results** from its **cold-worked minimum-property columns**:

| Published entry | Tensile strength | 0.2% yield strength |
| --- | ---: | ---: |
| Annealed, typical | 827 MPa | 310 MPa |
| Quarter-hard, minimum columns | 862 MPa | 517 MPa |
| Full-hard, minimum columns | 1276 MPa | 965 MPa |

The cold-worked table footnote says standard practice is to produce to either minimum tensile strength, minimum yield strength or minimum hardness, **not combinations of those properties**. Do not convert the columns into a simultaneous guarantee without an explicit order agreement. [Cleveland-Cliffs, tables 1–2 and footnote](https://d1io3yog0oux5.cloudfront.net/_6311866605bd18dd9ea6c0581df61600/clevelandcliffs/db/1190/10509/file/CLF_ProductData_301SS_052021.pdf#page=1)

For a **numerical comparison only**, the two published cold-worked tensile minima differ by `1276 − 862 = 414 MPa`, approximately `414 / 862 × 100 = 48%` of the quarter-hard value. This does not mean a finished spring carries 48% more load: geometry, yield behavior, fatigue, edge quality and stress concentration still govern its response.

Keep gauge length, thickness range, test direction and test temperature alongside elongation or strength data. Do not mix a typical annealed result, a minimum temper requirement and one shipment's test result into a single undifferentiated “material strength.”

## Forming and process planning

High strength and remaining formability must be selected together. The Cleveland-Cliffs bulletin warns that severe drawing/forming may require intermediate annealing and that some multiple-operation forming routes may be unsuitable. An intermediate anneal is a change in manufacturing condition, not merely a cleaning step. [Cleveland-Cliffs, formability section](https://d1io3yog0oux5.cloudfront.net/_6311866605bd18dd9ea6c0581df61600/clevelandcliffs/db/1190/10509/file/CLF_ProductData_301SS_052021.pdf#page=1)

Ulbrinox explains the relationship between elastic recovery and springback: greater resistance to plastic deformation changes forming behavior. Use trials representative of ordered thickness, temper, rolling direction, bend geometry and tooling rather than applying one universal minimum bend radius. [Ulbrinox, elastic and plastic deformation](https://www.ulbrinox.com.mx/en/blog/fundamentos-de-las-condiciones-de-templado-del-acero-inoxidable)

A practical route review should identify where the final properties are created and what later operations may change them. For a stamped part, retain the starting temper, forming direction, tooling setup, edge preparation and acceptance dimensions. For a spring, specify the relevant force-deflection requirement and fatigue qualification separately from the raw-strip tensile requirement. A material certificate alone does not demonstrate finished-part function.

## Corrosion, welding and heat exposure

ATI warns that carbide precipitation during welding can restrict Type 301 applications in favor of 304 or 304L. Its heat-treatment discussion describes annealing as stress removal, recrystallization and carbide solution treatment, with cooling requirements dependent on section. Thus a weld or thermal cycle needs review for both the required mechanical condition and corrosion performance. [ATI technical data sheet, corrosion resistance and heat treatment](https://www.atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/austenitic/ati_301_tds_en_v1.pdf#page=1)

Keep welding procedure, filler, joint geometry and postweld condition explicit. Do not assign the starting strip's cold-worked properties to a completed weldment without qualification. Document exposure temperature, duration, chemistry, chlorides, cleaning solutions and residual/applied stresses when judging service suitability. An oxidation-resistance statement is not a load-bearing temperature limit, and a short-term tensile test does not establish creep life or corrosion resistance.

## Ordering and source boundaries

Specify grade and standard edition; form, thickness and width; ordered temper and controlling mechanical requirements; finish and edge condition; test direction and certification. Where magnetic response or spring performance matters, specify its acceptance test rather than inferring it from the alloy name.

The Cleveland-Cliffs bulletin is printed May 2021. ATI's PDF is printed version 1, February 17, 2014. These are producer reference editions, not proof of the requirements in a later standard revision. No printed revision date was verified for the ATI, Outokumpu or Ulbrinox web pages. Confirm the governing contract editions and available supply before release.

See also [grades, tempers and conditions](../grades-tempers-and-conditions.md).