AISI 410

What is AISI 410?

AISI 410 is a basic martensitic stainless steel containing 11.5 to 13.5 percent chromium, 0.08 to 0.15 percent carbon and no more than 0.75 percent nickel. It hardens through austenitising, quenching to form martensite and tempering to obtain the required strength and toughness. The minimum chromium content provides stainless behaviour while limiting ferrite stabilisation, which would reduce martensite formation during quenching.

AISI 410 combines high strength with resistance to fresh water, steam, mild acids and food. Its corrosion resistance is the lowest among commonly used stainless steels and is below that of the 17 percent chromium ferritic grade AISI 430. Its ductility also decreases at sub-zero temperatures.

Carbon content distinguishes AISI 410 from AISI 420. AISI 410 contains no more than 0.15 percent carbon and reaches about 35 HRC minimum in the standard response test. AISI 420 begins at 0.15 percent carbon and reaches 50 HRC. AISI 410 is used where strength and toughness are required, while AISI 420 is used where greater hardness is required.

Laxcon Steels lists AISI 410 in its grades reference as a martensitic grade. The same steel is written 410, SUS 410, 1.4006 and S41000.

What is the chemical composition of AISI 410?

Composition limits in weight percent are carbon 0.08 to 0.15, manganese 1.0 maximum, sulphur 0.03 maximum, phosphorus 0.04 maximum, silicon 1.0 maximum, chromium 11.5 to 13.5 and nickel 0.75 maximum.

What is AISI 410 equivalent to in other standards?

Equivalence means nearest counterpart, not identity: each standards body sets its own composition window, so check the limits of the standard actually named on the order before substituting.

What is the PREN of AISI 410?

Computed by Laxcon Steels from the composition above as PREN = Cr + 3.3Mo + 16N, the relationship published in Practical Guidelines for the Fabrication of Duplex Stainless Steels (International Molybdenum Association, third edition, 2014). The published relationship is given for austenitic and duplex stainless steels, so this figure extends it: read it against other martensitic grades rather than across families. The first figure uses the minimum specified chromium, molybdenum and nitrogen, so it is the floor for a conforming heat rather than a typical value; the second uses the maxima, so the two together are the width of the band one compliant grade allows. PREN ranks resistance to chloride pitting and nothing else: it does not predict crevice corrosion, stress corrosion cracking or service life, and it is not a substitute for a corrosion test. The pitting resistance reference carries the full table and the caveats.

Mechanical properties by supply condition

ASTM A276 defines three conditions for AISI 410 bar. Annealed Condition A requires a minimum tensile strength of 480 MPa and a minimum 0.2 percent yield strength of 275 MPa. Minimum elongation is 20 percent for hot-finished material and 16 percent for cold-finished material. The minimum reduction of area is 45 percent. Condition T is hardened and tempered at a relatively high temperature. It requires 690 MPa tensile strength, 550 MPa yield strength and 15 percent elongation for hot-finished material. Condition H is hardened and tempered at a low temperature. It requires 830 MPa tensile strength, 620 MPa yield strength and 12 percent elongation.

ASTM A276 also specifies a response-to-heat-treatment test. The material must reach at least 35 HRC after heating to a minimum of 955 degrees Celsius and air quenching. This requirement verifies hardening capability and distinguishes AISI 410 from similar low-carbon material.

Published Atlas Steels data describe the properties obtained across the tempering range. Tempering at 204 degrees Celsius produces about 1,310 MPa tensile strength, 1,000 MPa yield strength, 16 percent elongation, 388 HB hardness and 30 J Charpy V impact energy. At 593 degrees Celsius, the corresponding values are about 870 MPa, 675 MPa, 20 percent, 255 HB and 39 J. At 650 degrees Celsius, they are 755 MPa, 575 MPa, 23 percent, 225 HB and 80 J. Strength decreases and toughness increases across these conditions.

Heat treatment

Full annealing consists of holding at 815 to 900 degrees Celsius, slowly furnace cooling to 600 degrees Celsius and then air cooling. Process annealing between forming operations uses 650 to 760 degrees Celsius followed by air cooling. Hardening requires heating to 925 to 1,010 degrees Celsius and quenching in oil or air. Oil quenching is necessary for heavy sections. Tempering generally occurs between 200 and 400 degrees Celsius.

Tempering between 400 and 580 degrees Celsius is generally avoided. Impact toughness decreases sharply in this range while hardness changes little. Atlas Steels identifies its 427 and 538 degrees Celsius conditions as unsuitable for this reason. Material tempered within this range may satisfy a hardness check despite having low impact toughness.

Corrosion behaviour

AISI 410 has a pitting resistance equivalent number of 11.5 at the specified minimum composition and 13.5 at the maximum composition. No grade with its own page in this reference has a lower value. The grade has adequate resistance to dry atmospheres, fresh water, steam, hot gases, food, mild alkalis and mild acids.

Maximum corrosion resistance occurs in the hardened and tempered condition rather than the annealed condition. In tempered martensite, less carbon is available to form chromium carbide. A smooth surface finish also improves performance because ground or polished surfaces provide fewer sites for disruption of the passive film. A machined, hardened and polished component therefore has different corrosion behaviour from an annealed component with an as-machined surface.

Welding, machining, applications and designations

Welding requires preheating to 150 to 260 degrees Celsius and post-weld annealing to reduce cracking risk. The weld and heat-affected zone form untempered martensite during cooling. Matching 410 filler is used when the joint will subsequently be hardened and tempered. Austenitic 309 filler provides a ductile joint that does not harden when the component will remain in the as-welded condition.

AISI 410 machines readily in the annealed or highly tempered condition. Machining becomes substantially more difficult above about 30 HRC. Machining may therefore precede final heat treatment when dimensional tolerances permit. Applications include bolts, nuts, screws, bushings, pump and valve parts, shafts, steam and gas turbine components, petroleum fractionating tower internals and mine ladder rungs.

The European designation is material number 1.4006, with the name X12Cr13. The UNS designation is S41000. The Japanese designation is SUS 410, also written without a space as SUS410 or SS410.

Where AISI 410 is not the right choice

AISI 410 is unsuitable for chlorides at any concentration. Its PREN of 11.5 to 13.5 and absence of molybdenum allow pitting in seawater, coastal air and chlorinated water. Rust staining can occur in environments where AISI 304 remains unaffected. AISI 431 contains 15.0 to 17.0 percent chromium and 1.25 to 2.50 percent nickel. It is the martensitic alternative where corrosion resistance and hardenability are both required. An austenitic grade is suitable where hardening is not required.

AISI 410 is unsuitable above about 650 degrees Celsius because scaling begins at that temperature. Service between 400 and 580 degrees Celsius is specifically not recommended because mechanical properties decrease in this range. The grade is also unsuitable for cryogenic or sub-zero service. Martensitic stainless steels undergo a ductile-to-brittle transition and lose toughness below room temperature. Austenitic grades do not show this behaviour.

AISI 416 is the free-machining martensitic alternative for heavily machined components. It cuts substantially faster but has lower corrosion resistance and weldability. AISI 420 is specified for components requiring hardness above about 40 HRC. AISI 410 is also unsuitable for welded fabrications when preheating and post-weld heat treatment cannot both be applied.

Other martensitic grades