Type 410
UNS S41000
Hardenable martensitic stainless steel · ASTM A240/A240M — chromium stainless steel plate, sheet and strip · ASTM A276/A276M — stainless steel bars and shapes · ASTM A480/A480M — general requirements for flat-rolled stainless steel under ASTM A240/A240M
Type 410 is the basic 12% chromium martensitic stainless steel. Unlike austenitic stainless grades, it can be quenched and tempered to obtain substantially increased strength and hardness, but its corrosion resistance, toughness and weldability are more limited. Product form and heat-treatment condition are essential parts of the specification: ASTM A240 governs annealed flat products, while ASTM A276 provides distinct annealed and hardened-and-tempered property classes for bars and shapes.
- 0.08–0.15% C and 11.5–13.5% CrDefining composition · The carbon range permits martensitic hardening; the relatively modest chromium level provides moderate rather than austenitic-grade corrosion resistance.
- Quench and temperHeat-treatable · Strength, hardness, toughness and corrosion performance depend strongly on austenitizing, quenching and tempering practice.
- 450 MPa tensile; 205 MPa yieldA240 flat-product minimum strength · Annealed plate, sheet and strip; elongation is 20% minimum in 50 mm and hardness is 217 HBW or 96 HRBW maximum.
- 480 to 830 MPa minimum tensile, depending on conditionA276 bar strength range · The applicable minimum changes from Condition A to T or H; finish also affects specified ductility.
- ModerateCorrosion class · Suitable for mild atmospheres, fresh water, steam and selected weak media; generally unsuitable for chloride-rich or strongly acidic service without application
- FerromagneticMagnetic behavior · Type 410 remains strongly magnetic in normal annealed and hardened conditions.
Overview
- Designation system
- AISI type designation with UNS identifier
- Product forms
- Plate, Sheet, Strip, Hot-finished bar, Cold-finished bar, Hot-rolled or extruded shapes
- Condition
- Annealed flat product under ASTM A240/A240M, ASTM A276 Condition A — annealed, ASTM A276 Condition T — hardened and tempered at a relatively high temperature, ASTM A276 Condition H — hardened and tempered at a relatively low temperature
- Density
- 7.75 g/cm³ (Representative physical-property value; density is not an ASTM A240/A276 acceptance requirement.)
What the designation establishes
Type 410 identifies a wrought martensitic stainless steel composition, not a universal set of mechanical properties. UNS S41000 is the principal composition identifier. The applicable product specification then establishes the permissible form, delivery condition, mechanical requirements, dimensions, testing and certification.
| Specification | Scope relevant to Type 410 | Practical consequence |
|---|---|---|
| ASTM A240/A240M | Plate, sheet and strip for pressure-vessel and general applications | Provides flat-product chemistry and annealed mechanical-property requirements. It does not define hardened-and-tempered strength classes for finished components. |
| ASTM A276/A276M | Hot-finished or cold-finished bars and hot-rolled or extruded shapes | Permits Type 410 in Conditions A, T and H, with condition- and finish-dependent mechanical requirements. |
| ASTM A480/A480M | General requirements associated with ASTM A240 flat products | Controls matters such as ordering information, dimensions, tolerances, workmanship, testing, inspection, marking and permissible variations unless superseded by ASTM A240 or the purchase order. |
Calling out only “Type 410” or “S41000” is insufficient where strength, hardness, dimensions, finish, pressure-service status or certification matters. The product specification and delivery condition must also be stated.
Chemical composition and specification differences
| Element | ASTM A240/A240M flat product | ASTM A276/A276M bar and shapes |
|---|---|---|
| Carbon | 0.08–0.15 | 0.08–0.15 |
| Manganese | 1.00 max | 1.00 max |
| Phosphorus | 0.040 max | 0.040 max |
| Sulfur | 0.030 max | 0.030 max |
| Silicon | 1.00 max | 1.00 max |
| Chromium | 11.5–13.5 | 11.5–13.5 |
| Nickel | 0.75 max | Not individually specified |
| Iron | Balance | Balance |
Values are specification limits, not a typical melt analysis. Product-analysis tolerances, where applicable, are governed by the relevant ASTM requirements.
The nickel distinction is a useful example of why chemistry from different product specifications should not be merged into one generic Type 410 table. ASTM A240 places a maximum on nickel for S41000 flat product, whereas ASTM A276 does not individually specify nickel for the bar grade. Material must be evaluated against the actual specification named on the order or drawing.
Mechanical requirements depend on product form and condition
| Property | Requirement |
|---|---|
| Tensile strength | 65 ksi / 450 MPa minimum |
| 0.2% offset yield strength | 30 ksi / 205 MPa minimum |
| Elongation in 2 in. or 50 mm | 20% minimum |
| Hardness | 217 HBW or 96 HRBW maximum |
Inch-pound and SI requirements are separate standard systems and should not be mixed for conformity assessment.
| Condition and finish | Tensile strength, min | 0.2% yield strength, min | Elongation, min | Reduction of area, min |
|---|---|---|---|---|
| A — hot-finished | 70 ksi / 480 MPa | 40 ksi / 275 MPa | 20% | 45% |
| A — cold-finished | 70 ksi / 480 MPa | 40 ksi / 275 MPa | 16% | 45% |
| T — hot-finished | 100 ksi / 690 MPa | 80 ksi / 550 MPa | 15% | 45% |
| T — cold-finished | 100 ksi / 690 MPa | 80 ksi / 550 MPa | 12% | 40% |
| H — hot-finished | 120 ksi / 830 MPa | 90 ksi / 620 MPa | 12% | 40% |
| H — cold-finished rounds | 120 ksi / 830 MPa | 90 ksi / 620 MPa | 12% | 40% |
Condition A is annealed. Condition T uses relatively high-temperature tempering; Condition H uses relatively low-temperature tempering. ASTM A276 does not assign one universal hardness requirement to these Type 410 rows.
ASTM A240 annealed flat-product values must not be substituted for ASTM A276 bar values. Likewise, a mill certificate for annealed Condition A bar does not demonstrate that a subsequently hardened component meets Condition T or H properties.
Heat treatment and resulting metallurgy
Annealed Type 410 contains a relatively soft ferritic matrix with chromium-rich carbides. Heating into the austenitizing range dissolves part of the carbide population and forms austenite. Air or oil cooling then produces predominantly martensitic structure. Tempering relieves quench stresses and adjusts the balance among hardness, tensile strength, ductility, impact toughness and corrosion resistance.
| Operation | Representative range or practice | Purpose and caution |
|---|---|---|
| Process anneal | Approximately 650–760°C, followed by air cooling | Restores workability without necessarily giving maximum softness. |
| Full anneal | Approximately 815–900°C, followed by controlled furnace cooling and then air cooling | Produces a softer machining or forming condition. |
| Austenitize and harden | Approximately 925–1010°C, followed by air or oil quenching as appropriate to section size | Produces martensite. Heavy sections generally require more severe cooling than thin sections. |
| Low-temperature temper | Generally used where high strength and hardness are the priority | Retains high hardness but provides lower toughness than a high-temperature temper. |
| High-temperature temper | Used to improve ductility and toughness at lower strength and hardness | Commonly preferred for highly stressed mechanical parts where toughness is important. |
| Intermediate tempering band | Approximately 400–580°C is commonly avoided | This region can produce poor impact toughness and may reduce corrosion resistance. A qualified heat-treatment procedure should control temperature, time and cooling. |
These are representative industry ranges rather than substitute acceptance requirements. The required cycle depends on section size, furnace practice, target properties and governing component specification.
Hardening response varies with actual carbon content, section size and quench severity. A heat near the lower carbon limit cannot be assumed to achieve the same maximum hardness as material near the upper limit. Final component properties should therefore be specified and verified directly rather than inferred solely from the Type 410 designation.
Corrosion, temperature and service behavior
Type 410 provides useful resistance to dry or mildly contaminated atmospheres, fresh water, steam, hot gases, mild alkalis and selected weak chemical environments. Its corrosion resistance is below that of common austenitic grades such as 304 and below higher-chromium ferritic grades such as 430. It should not be treated as a general-purpose material for seawater, salt spray, stagnant chloride solutions or reducing acids.
Surface condition and heat treatment are unusually important. Smooth, clean and properly passivated surfaces generally perform better than scaled or rough surfaces. Hardened, appropriately tempered and polished material normally offers the best corrosion performance. Tempering that causes extensive chromium-carbide precipitation can locally deplete chromium and reduce resistance.
Oxidation-resistance figures around 650°C are sometimes published for Type 410, but they are not general mechanical service limits. At elevated temperature the original temper can be altered, strength can fall, and dimensional or toughness requirements may no longer be maintained.
Fabrication implications
| Process | Practical guidance |
|---|---|
| Machining | Usually machined in an annealed or highly tempered condition. Very soft material can be tough and produce built-up edge, while hardness above roughly 30 HRC makes conventional machining progressively more difficult. |
| Cold forming | Moderate blanking, bending, drawing and heading are possible in the annealed condition. Formability is well below that of austenitic stainless steel, and deformation may require intermediate annealing. |
| Hot working | Type 410 can be forged, headed and upset, but it is stronger at forging temperatures than plain carbon steel. Controlled cooling or subsequent annealing is normally needed before machining. |
| Grinding | Hardened parts require appropriate wheel selection and conservative grinding practice to avoid burns, local retempering and tensile residual stresses. |
| Cleaning and passivation | Remove heat tint, embedded iron, scale, lubricants and shop contamination. Passivation can restore a clean chromium-rich surface but cannot compensate for unsuitable heat treatment or severe chloride exposure. |
Welding requires particular care because the base metal and heat-affected zone can transform to hard, crack-sensitive martensite. Preheat, controlled interpass temperature, low-hydrogen practice and timely post-weld heat treatment may be required depending on thickness, restraint and service. Matching E410 or ER410 consumables are used where a heat-treatable matching weld is needed; austenitic fillers such as 309 may improve as-welded joint ductility but produce a dissimilar weld metal with different strength, thermal and service behavior. The welding procedure must be qualified for the actual construction code and component condition.
Specifying and purchasing Type 410
| Item | Why it matters |
|---|---|
| Product specification and edition | Separates A240 flat-product requirements from A276 bar and shape requirements and fixes the contractual rules. |
| UNS/type designation | State S41000 or Type 410; do not rely on the generic description “410 stainless” alone. |
| Product form and dimensions | Controls applicable tolerances, sampling and test requirements. |
| Delivery condition | For ASTM A276, explicitly state A, T or H. If the purchaser will perform final hardening, state the required incoming condition. |
| Finish and surface condition | Important for dimensional control, machinability, appearance and corrosion performance. |
| Required final hardness or mechanical properties | Especially important for finished components because the standard mill condition may not represent the final heat-treated part. |
| Heat-treatment responsibility | Clarify whether the mill, distributor, machine shop or component manufacturer performs final hardening and tempering. |
| Testing and certification | Define the required material test report, heat traceability, hardness location, tensile testing, nondestructive examination and any supplementary requirements. |
| Corrosion or sour-service requirements | Type 410 designation alone does not establish suitability for a specific fluid, chloride level, pressure code or environmental cracking standard. |
For substitution, compare the complete product specification, chemistry, condition, mechanical properties, heat treatment, dimensions, manufacturing route, testing and service requirements. A nominal cross-reference to another national grade is not sufficient approval.
Sources
- ASTM A240/A240M-26 — Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General ApplicationsASTM International
- ASTM A276/A276M-25 — Standard Specification for Stainless Steel Bars and ShapesASTM International
- ASTM A480/A480M — Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and StripASTM International
- Stainless Steel Grade Sheets — Grade 410worldstainless
- Outokumpu Dura Range DatasheetOutokumpu
- CarTech 410 Stainless Technical DatasheetCarpenter Technology
- ATI 410ATI Inc.
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