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AISI 410 / (1.4006) / UNS S41000 / AMS 5504 / AMS 5505

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Corrosion resistance: The corrosion resistance of AISI 410 is not very good and this grade should not be used in severely corrosive environments.

Weldability: This grade contains around 0.12% carbon, and although that carbon content makes welding less than straightforward, welding this material is possible.​‌​​‌​

Machinability: This grade has machinability that can be considered medium to good in terms of cutting speed and chip breaking during machining, and the material is not difficult to machine.

Heat treatment: 1.4006 is delivered in both the annealed and the quenched and tempered conditions. The annealed condition is obtained by heating in the range 745 °C to 825 °C followed by slow cooling in a furnace. It can be heat treated by hardening in air or oil after holding at a temperature between 950 and 1000 °C. Although a range of mechanical properties can be obtained by tempering at different temperatures, the QT 650 condition is generally specified and can be obtained by tempering in the range 680 °C to 780 °C.​‌​​‌​

Applications: AISI 410 stainless steel is frequently used in the machinery industry, in gas turbine components, in steam turbines, in the petrochemical industry, in valve parts, in pump parts and in components such as bolts and nuts.

AISI 410 provides high hardness and wear resistance while also making high temperature capability possible. These properties allow the steel to be used in applications requiring durability. Its corrosion resistance is nevertheless lower than that of the austenitic steels in particular.​‌​​‌​

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Standards by Product Form

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AISI 410 is the original hardenable martensitic stainless grade, with 11.5–13.5% chromium. Two points govern the order: 410, 410S and 410NiMo are three distinct alloys (not tolerance variants of one grade), and the material must be ordered with its heat-treat condition stated — writing only “ASTM A276 Type 410” fixes the chemistry, not the mechanical properties.

Composition (ASTM A240 / A276): C 0.08–0.15% · Cr 11.5–13.5% · Mn ≤1.00% · Si ≤1.00% · P ≤0.040% · S ≤0.030% · Ni ≤0.75%. Annealed minimums: sheet/plate (A240) tensile ≥ 450 MPa, yield ≥ 205 MPa, elongation ≥ 20%, hardness ≤ 217 HB / 96 HRB; bar (A276 Condition A) tensile ≥ 480 MPa, yield ≥ 275 MPa, elongation ≥ 20%, reduction of area ≥ 45%. Hardened, tensile reaches the 690 MPa (Cond. T) and 830 MPa (Cond. H) classes, and typically exceeds 1400 MPa at a low temper — which is exactly why the condition must appear on the specification.

Catalogue trap: some listings show “ASTM A403 WP410” for 410 fittings. A403 is titled Wrought Austenitic Stainless Steel Piping Fittings; martensitic grades fall under A815. Likewise, AMS 5612 and AMS 5613 are annealed-condition specifications — “AMS 5613 bar” guarantees no hardness or strength level.​‌​​‌​

Welding, Heat Treatment and Machining

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Welding

SMAW, GTAW, GMAW and SAW are all usable. Because 410 is air-hardening, preheat is mandatory: at least 177–204 °C (350–400 °F), maintained throughout welding, with interpass held at or above preheat. A full anneal must follow immediately, before the weldment cools — otherwise the HAZ is left as untempered, crack-prone martensite with degraded corrosion resistance. For a matching deposit use ER410 / E410-XX; where cracking risk is high, or for dissimilar joints to carbon steel, use ER309L / E309L or a nickel-base filler (ERNiCr-3). Low-hydrogen practice is essential.​‌​​‌​

Heat treatment

A fully martensitic-hardening 12–13% Cr alloy. Austenitising: 925–1010 °C, oil quench (air for thin sections). Tempering has two usable windows: below about 370 °C for maximum hardness, or 565–760 °C for toughness. Tempering between 400 and 565 °C (750–1050 °F) is forbidden — two separate producers (Rolled Alloys, Carpenter) publish near-identical warnings that both impact toughness and corrosion resistance drop. This is not the same mechanism as the “475 °C embrittlement” of ferritic and duplex grades; do not conflate them. Full anneal: 815–899 °C, furnace cool to about 593 °C, then air cool, giving 187–217 HB. Process (sub-critical) anneal: 649–788 °C, air cool. Standard delivery is annealed.​‌​​‌​

Machining

Machinability is roughly 55% of B1112. Dead-soft annealed material is tough and draggy with poor chip control; cold-drawn or lightly heat-treated bar gives a better finish. Use sharp edges with a tight chip breaker; carbide tooling allows 2–3× the surface speed of HSS. Flood coolant is required. Above 30 HRC machinability falls sharply — where extensive machining is required, AISI 416 is the usual substitute. Passivate after machining.​‌​​‌​

410, 410S, 410NiMo and Neighbouring Grades

The most common catalogue error is listing three different alloys under one “410” heading. They are separate stock items:​‌​​‌​

Service limits: approximately 649 °C continuous and 816 °C intermittent in air (an oxidation limit). Mechanical properties nevertheless decline in the 400–580 °C band, so sustained loaded service there is not recommended. Corrosion: resists atmosphere, fresh water, steam, dilute organic and inorganic acids, food acids and mild alkalis; it does not resist chlorides — it is not a seawater-service grade. Best corrosion performance is obtained hardened and polished. The grade is magnetic.​‌​​‌​

Frequently Asked Questions

What is the difference between 410, 410S and 410NiMo, and which should I stock?​‌​​‌​

These are three distinct alloys, not tolerance variants of one grade. 410 (C 0.08–0.15%) is the fully hardenable standard martensitic — order it when the part will be heat-treated for strength or wear resistance. 410S (C ≤0.08%) is a restricted-carbon variant that stays soft even after rapid cooling; it is the fabricability choice for cladding, liners and equipment whose HAZ must not harden, but it cannot be through-hardened for strength. 410NiMo (S41500 / A182 F6NM; Ni 3.5–5.5%, Mo 0.5–1.0%) gives a soft, tough martensite with distinctly better low-temperature toughness and pitting resistance, at a higher price, and is normally specified for critical forged valve and pump bodies. In practice: stock 410 for general hardened parts, supply 410S only when a customer fabrication spec calls for it, and bring in 410NiMo only against a specific F6NM order.

Why is “ASTM A276 Type 410” not enough on a purchase order?​‌​​‌​

Because that wording fixes only the chemistry. Mechanical properties swing over a wide band with heat treatment: annealed Condition A gives about 480 MPa tensile / 275 MPa yield, while low-temper Condition H reaches roughly 830 MPa tensile / 620 MPa yield — close to a two-fold difference. Material certified simply as “Type 410, Condition A” is soft, machinable and comparatively weak bar. If your drawing calls out a minimum yield or a hardness range, the purchase order must state the condition (A / T / H) — and, for aerospace or critical parts, the AMS 2759/5 heat-treat class — and you must confirm that the mill certificate reports test results for that condition.

Can I substitute 430 for 410?​‌​​‌​

No; the two are not interchangeable, and the difference is structural rather than cosmetic. 430 is ferritic and cannot be hardened by heat treatment; its strength is fixed whatever the thermal cycle, though its 16–18% chromium gives slightly better general atmospheric corrosion resistance than 410. 410 is martensitic and can be heat-treated into the 690–830 MPa tensile classes, at the cost of somewhat lower general corrosion resistance and a mandatory preheat plus post-weld anneal if it is welded. Where strength, hardness or wear resistance is required (shafts, valve seats, cutting edges) use 410; where only formability and moderate corrosion resistance are needed (decorative trim, mild chemical exposure) 430 is the cheaper and easier-to-fabricate choice. Never swap one for the other on a strength- or hardness-critical print.

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