# Type 410 stainless steel

Selecting hardenable UNS S41000 by form and thermal condition, with bounded sheet-test values, corrosion guidance and welding controls.

Reviewed: 2026-11-01

Tags: materials, stainless-steel, martensitic

## Identity and purchasing basis

ATI's **typical** data for **410 with 0.14% carbon** list **313 MPa yield and 554 MPa tensile annealed**. After hardening, its **204°C temper** gives **1,076 MPa yield, 1,399 MPa tensile and 43 HRC**. Its **649°C temper** gives **589 MPa yield, 767 MPa tensile and 98 HRB**. Keep the heat-treatment condition and hardness scale with the result. [ATI typical mechanical table](https://www.atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/martensitic/ati_410_420_425_mod_440a_440c_tds_en2_v2.pdf)

Type 410, **UNS S41000**, is a hardenable martensitic stainless steel. Carpenter's type analysis lists **11.50–13.50% chromium** and **carbon ≤0.15%**, together with other controlled elements. The designation does not establish whether delivered material is annealed, hardened or tempered to a particular property combination. [Carpenter 410 data sheet](https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/410.pdf)

Specify the exact product standard and edition, supplied form, dimensions, starting condition, required final condition and inspection documents. Keep sheet, bar, forging and a completed welded component separate. A producer's grade description cannot replace an order-specific certificate or establish the properties of an unidentified part.

Treat Type 410 separately from low-carbon 410L, free-machining variants and higher-carbon martensitic grades. Similar names do not establish equivalent hardening response, fabrication behavior or corrosion performance. Resolve the full designation before comparing property numbers.

## A condition-specific mechanical example

ATI's combined martensitic-stainless bulletin reports these **typical characterization results for ATI 410 with 0.14% carbon**. They are not specification minima or design allowables. [ATI martensitic stainless-steel bulletin, typical mechanical table](https://www.atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/martensitic/ati_410_420_425_mod_440a_440c_tds_en2_v2.pdf)

| Reported condition | Hardness | 0.2% yield strength | Tensile strength |
| --- | ---: | ---: | ---: |
| Annealed | 81 HRB | 313 MPa | 554 MPa |
| Hardened, tempered at 400°F (204°C) | 43 HRC | 1076 MPa | 1399 MPa |
| Hardened, tempered at 1200°F (649°C) | 98 HRB | 589 MPa | 767 MPa |

For the hardened entries, ATI used **sheet samples heated at 1800°F (982°C) for 60 minutes per inch**, air cooled to room temperature, then tempered for **two hours** at the stated temperature. That test route is part of the evidence; it is not a qualified furnace recipe for every section. [ATI table explanation](https://www.atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/martensitic/ati_410_420_425_mod_440a_440c_tds_en2_v2.pdf)

Keep tensile strength, yield strength, hardness and allowable design stress separate. A hardness reading alone cannot reconstruct an undocumented thermal cycle, prove toughness or establish fatigue life. Where an application needs those properties, define the required evidence explicitly.

## Heat-treatment planning

ATI emphasizes that freshly quenched martensite is brittle and requires tempering to restore ductility. The treatment chosen changes the balance of hardness and strength. [ATI heat-treatment discussion](https://www.atimaterials.com/Products/Documents/datasheets/stainless-specialty-steel/martensitic/ati_410_420_425_mod_440a_440c_tds_en2_v2.pdf)

Establish the required final mechanical and corrosion properties before selecting the process. Record incoming condition, prior deformation, austenitizing, cooling, tempering and required verification. Define machining allowance and the stage at which final dimensions are accepted. A short instruction to “harden 410” leaves the intended state unresolved.

For a complex component, qualify distortion and local response on representative geometry. Include holes, thick sections and restrained features in the review. Do not infer through-section properties from a surface measurement without the necessary sampling or process evidence.

## Corrosion and temperature boundaries

Carpenter describes resistance in mild atmospheres for both annealed and heat-treated material, but its comparison chart rates sulfuric acid, phosphoric acid, acetic acid and sour oil/gas as **restricted**. The chart is comparative and recommends testing; it does not assign universal concentration or temperature limits. [Carpenter corrosion guidance](https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/410.pdf)

For a compatibility assessment, document chemistry, concentration, pH, contaminants, temperature, aeration, velocity, deposits, crevices, stress and surface condition. Include cleaning, shutdown and upset conditions. An application list or the word “stainless” cannot establish a maintenance interval or guarantee a cosmetic surface.

Carpenter's **1200°F (649°C)** scaling statement concerns resistance to scaling/oxidation. It does not establish permissible stress or service life at that temperature. [Carpenter description and scaling section](https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/410.pdf)

For hot service, assess actual metal temperature, exposure duration, load and thermal cycles. Keep oxidation, creep, strength and toughness evidence separate. Where service requirements differ from the published test conditions, seek producer advice or representative qualification instead of creating a single maximum operating temperature.

## Welding and machining

Carpenter identifies **E/ER410** as a filler option, calls for preheating to prevent cracking, particularly in heavy or intricate parts, and recommends immediate postweld annealing to obtain uniformly ductile sections. These are its product recommendations, not qualification of a particular joint. [Carpenter weldability section](https://www.carpentertechnology.com/hubfs/7407324/Material%20Saftey%20Data%20Sheets/410.pdf)

Resolve base-material condition, joint geometry, filler, shielding, thermal controls, sequence and inspection through the approved procedure. Review dissimilar joints and repairs separately. If annealing conflicts with a required hardened final state, the complete route must resolve both requirements; a satisfactory bead appearance cannot establish joint properties.

Plan machining around the actual starting and final conditions, tool rigidity, feature geometry and required finish. Qualify parameters on representative stock rather than treating published cutting tables as guaranteed rates. Inspect critical dimensions after operations capable of changing them.

Define cleaning and surface acceptance for the final service. Keep repair and thermal history connected to the component when those operations alter the original condition. Obtain current handling information and the facility procedure appropriate to the operation and generated material.

## Bounded calculation and release record

**Original nominal-stress example:** a uniform 100 mm² section carrying 5,000 N has stress **50 MPa**. Relative to ATI's typical annealed yield entry, **50/313 ≈0.160**. This ratio is not a safety factor: it uses characterization data and omits actual properties, local stress, defects, fatigue, corrosion loss, joints and design rules.

At release, retain specification, producer, heat/lot, certificate, drawing, delivered/final condition and processing records with required inspection. Establish dimensional, leak, fatigue or corrosion acceptance where the component needs it. Resolve substitutions against the complete record rather than one favorable property result.

## Source versions

ATI's inspected bulletin prints **Version 1, 18 February 2014**. Carpenter's PDF prints **Edition Date: 05/01/1987** and a separate **©2020** notice; the numeric edition string is retained without assigning an ambiguous day/month interpretation. These are source identities, not evidence of current contractual standard editions. Sources reviewed **2026-11-01, America/Los_Angeles**.

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