X5CrNi18-10
1.4301
Austenitic chromium-nickel corrosion-resistant stainless steel · EN 10088-1:2023 — list, composition and guidance physical properties · EN 10088-2:2024 — sheet, plate and strip for general purposes · EN 10088-3:2023 — semi-finished products, bars, rods, wire, sections and bright products for general purposes · EN 10088-4:2009 — flat products for construction purposes · EN 10088-5:2009 — long products for construction purposes
X5CrNi18-10 / 1.4301 is the standard European 18Cr-8Ni austenitic stainless steel commonly associated with Type 304. It combines broad general-purpose corrosion resistance, high ductility, excellent formability and straightforward weldability, but contains no deliberate molybdenum addition and therefore has limited resistance to chloride pitting, crevice corrosion and chloride stress-corrosion cracking. Its mechanical requirements are defined by the applicable product standard, dimensions and delivery condition—not by the grade designation alone.
- Cr 17.5–19.5%; Ni 8.0–10.5%; C ≤0.07%Defining composition · Cast-analysis limits under the current EN 10088 grade definition.
- Austenitic in the solution-annealed conditionMetallurgical structure · Normally essentially non-magnetic when annealed, but cold work can produce magnetic martensite.
- Rp0.2 ≥230 MPa and Rm 540–750 MPa for cold-rolled product up to 8 mmFlat-product strength · EN 10088-2:2024, solution-annealed condition; hot-rolled strip and plate have different values.
- Rp0.2 ≥190 MPa and Rm 500–700 MPa up to 160 mmLong-product strength · EN 10088-3:2023 for solution-annealed semi-finished products, bars and sections; not the bright-bar or cold-worked table.
- Solution anneal at 1000–1100 °C, followed by sufficiently rapid air or water coolingHeat treatment · Used to dissolve carbides, remove cold-work effects and restore the austenitic condition.
- Not a chloride-resistant substitute for molybdenum-bearing gradesPrincipal service limitation · Grade selection must account for chloride concentration, temperature, deposits, crevices, cleaning regime and tensile stress.
Overview
- Designation system
- EN steel name and steel number according to EN 10027; grade listed in EN 10088-1
- Product forms
- Cold-rolled and hot-rolled strip, sheet and plate, Bars, rods, sections, wire and bright products, Seamless and welded tube under applicable tube standards, Pressure-purpose plate, tube, bar, forgings and fittings under their dedicated product standards, Fabricated components and cold-formed products
- Condition
- Solution annealed (+AT or product-route equivalent), Hot-rolled or cold-rolled with specified process route and surface finish, Cold-worked strength condition where permitted by the product standard, Cold-drawn or bright-finished condition
- Density
- 7.9 g/cm³ (Guidance value at approximately 20 °C from EN 10088-1; also used for nominal mass calculations. It is not normally an acceptance property.)
What the designation means
The steel name is composition based. “X” identifies a high-alloy steel; “5” represents a nominal carbon content of about 0.05% when multiplied by 100; “CrNi” identifies the principal alloying elements; and “18-10” gives their nominal percentages. These figures explain the name but do not replace the specified composition limits. In particular, the nickel range for 1.4301 is 8.0–10.5%, so the designation does not guarantee exactly 10% nickel.
The steel number 1.4301 is the unambiguous European identifier. “304,” “S30400,” “18/8” and “V2A” are widely associated names, but only the complete governing product specification establishes contractual chemistry, properties, dimensions, finish, testing and certification.
Grade chemistry
| Element | Requirement, mass % | Technical significance |
|---|---|---|
| C | ≤0.07 | Higher permitted carbon than 1.4307; relevant to sensitization during prolonged thermal exposure. |
| Si | ≤1.00 | Deoxidizer; contributes modestly to oxidation behavior. |
| Mn | ≤2.00 | Austenite-forming and steelmaking addition. |
| P | ≤0.045 | Residual element controlled for quality and fabrication behavior. |
| S | ≤0.015 | Low baseline limit; product standards may permit agreed sulfur ranges for particular weldability or machinability objectives. |
| Cr | 17.5–19.5 | Forms and maintains the passive chromium-rich surface film. |
| Ni | 8.0–10.5 | Stabilizes austenite and supports ductility, formability and corrosion performance. |
| N | ≤0.10 | Austenite stabilizer and strength contributor; not intentionally specified at the level used in nitrogen-alloyed grades. |
The limits above define cast analysis. Permitted product-analysis deviations, where applicable, are governed by the relevant product standard and must not be confused with the cast-analysis limits.
Product standards control the delivered properties
| Standard | Scope and significance |
|---|---|
| EN 10088-1:2023 | Lists the grade, defining composition and guidance physical properties. It is not by itself a complete purchasing specification. |
| EN 10088-2:2024 | General-purpose hot- and cold-rolled sheet, plate and strip. Defines process routes, finishes, condition-dependent mechanical properties, inspection and ordering information. |
| EN 10088-3:2023 | General-purpose semi-finished products, bars, rods, wire, sections and bright products. Property requirements vary with form, dimension and condition. |
| EN 10088-4:2009 | Flat products specifically supplied for construction purposes. |
| EN 10088-5:2009 | Bars, rods, wire, sections and bright products supplied for construction purposes. |
| Dedicated pressure and tube standards | Pressure plate, pipe, tube, forgings, fittings and bars must be ordered to their applicable standards. Requirements from EN 10088-2 or EN 10088-3 must not be assumed to apply. |
The designation 1.4301 identifies a chemical grade, not a universal property set. A cold-rolled sheet, hot-rolled plate, solution-annealed bar, cold-drawn bright bar and welded pressure tube can all carry this grade designation while having different mechanical requirements, surfaces, test orientations, inspection regimes and dimensional tolerances.
Room-temperature mechanical properties
| Product code and form | Maximum thickness | Rp0.2 min. | Rp1.0 min. | Rm | Elongation min. |
|---|---|---|---|---|---|
| C — cold-rolled strip | 8 mm | 230 MPa | 260 MPa | 540–750 MPa | 45% |
| H — hot-rolled strip | 13.5 mm | 210 MPa | 250 MPa | 520–720 MPa | 45% |
| P — hot-rolled plate | 75 mm | 210 MPa | 250 MPa | 520–720 MPa | 45% |
Elongation gauge length and specimen requirements are defined by the standard. Narrow strip, continuously hot-rolled products and impact testing involve additional provisions.
| Relevant dimension | Rp0.2 min. | Rp1.0 min. | Rm | Elongation min. | Hardness max. |
|---|---|---|---|---|---|
| ≤160 mm | 190 MPa | 225 MPa | 500–700 MPa | 45% | 215 HBW |
| 160 < dimension ≤250 mm | 190 MPa | 225 MPa | 500–700 MPa | 35% | 215 HBW |
Applies to the standard's solution-annealed semi-finished products, bars and sections, subject to its detailed dimensional, sampling and orientation rules. Rod, wire, bright-bar and cold-worked requirements are not represented by this table.
The relatively low 0.2% proof strength and high elongation are characteristic of annealed austenitic stainless steel. The material work-hardens strongly, so formed or cold-drawn products can have much higher strength and hardness than the solution-annealed values. Such properties must be ordered through a defined cold-worked strength condition rather than inferred from the grade name.
Metallurgy and physical behavior
| Property | Guidance value | Practical consequence |
|---|---|---|
| Density | 7.9 g/cm³ | Suitable for nominal mass calculations. |
| Elastic modulus at 20 °C | 200 GPa | Similar initial stiffness to carbon steel, despite lower annealed proof strength. |
| Mean thermal expansion, 20–100 °C | 16.0 × 10⁻⁶ K⁻¹ | Higher than carbon steel; allow for movement and welding distortion. |
| Mean thermal expansion, 20–500 °C | 18.0 × 10⁻⁶ K⁻¹ | Thermal movement becomes increasingly important in restrained assemblies. |
| Thermal conductivity at 20 °C | 15 W/(m·K) | Substantially lower heat conduction than carbon steel, concentrating welding and machining heat. |
| Specific heat capacity at 20 °C | 500 J/(kg·K) | Guidance value for thermal calculations. |
| Electrical resistivity at 20 °C | 0.73 Ω·mm²/m | Much higher resistance than carbon steel. |
| Magnetic response | Essentially non-magnetic when fully annealed | Cold work, sheared edges, machining and weld ferrite can produce measurable magnetic attraction. |
These are guidance data, not normal acceptance requirements.
1.4301 cannot be hardened by conventional quench-and-temper heat treatment. Strengthening occurs primarily by cold deformation. Because its austenite is metastable, cold work can also transform part of the structure to ferromagnetic martensite. A magnet test is therefore unsuitable as a definitive grade-identification method.
Solution annealing at 1000–1100 °C followed by sufficiently rapid cooling dissolves chromium carbides, removes most cold-work strengthening and restores a predominantly austenitic structure. Local heat treatment of a completed fabrication can cause distortion or surface oxidation and should be undertaken only with an appropriate procedure.
Corrosion behavior and service boundaries
1.4301 gives reliable general-purpose resistance in many atmospheric, food-processing, domestic, architectural and mildly oxidizing environments when the surface remains clean and passive. Its chromium-nickel composition makes it substantially more corrosion resistant than ordinary steels, but “stainless” does not mean immune to corrosion.
| Mechanism | Assessment for 1.4301 | Engineering implication |
|---|---|---|
| Pitting and crevice corrosion | Limited resistance in chloride-bearing environments because the grade has no deliberate molybdenum addition. | Temperature, chloride concentration, deposits, crevices, oxidants and cleaning frequency must be considered. 1.4401/1.4404 or more highly alloyed grades are often evaluated when chloride severity increases. |
| Chloride stress-corrosion cracking | Standard austenitic stainless steels can crack when chlorides, tensile stress and sufficiently elevated temperature occur together. | Residual welding or forming stress can be significant. Grade selection must address the actual temperature and chloride exposure rather than relying on general atmospheric performance. |
| Intergranular corrosion | EN 10088 product tables recognize resistance in the delivered solution-annealed condition, but 1.4301 is not guaranteed resistant after sensitizing exposure. | For welded structures facing aggressive corrosive service or later thermal cycles, the low-carbon grade 1.4307 or a stabilized grade may be preferable. |
| Surface contamination and heat tint | Embedded carbon steel, weld oxide, scale and fabrication contamination can locally damage passivity. | Use stainless-dedicated tools where appropriate and specify cleaning, pickling or passivation according to service requirements. |
| Galvanic corrosion | The stainless steel may remain cathodic while a less noble coupled metal corrodes. | Review area ratio, electrical continuity and electrolyte exposure in mixed-metal assemblies. |
No single chloride concentration or temperature is a universal safe limit. Water chemistry, oxygen availability, flow, deposits, crevice geometry, surface finish and residual stress can alter performance substantially.
The grade can retain useful toughness at low temperature because solution-annealed austenitic stainless steels do not exhibit the pronounced ductile-to-brittle transition typical of ferritic carbon steels. Conversely, a maximum elevated-temperature service limit cannot be assigned from the grade designation alone: oxidation, creep, sensitization, pressure-code rules and load duration must all be considered.
Forming, machining and welding
| Operation | Behavior | Practical control |
|---|---|---|
| Cold forming | Excellent ductility and deep-drawing capability, accompanied by substantial work hardening and springback. | Allow higher forming loads than the initial proof strength suggests; use suitable bend radii, tooling and intermediate annealing if severe multi-stage deformation demands it. |
| Cutting and machining | Work hardening, low thermal conductivity and ductile chips can reduce tool life. | Use rigid equipment, sharp positive-geometry tooling, adequate feed and cooling; avoid rubbing or dwelling on the surface. |
| Welding | Readily welded by established fusion processes; preheating is not normally required. | Use a qualified welding procedure, control heat input and distortion, and select consumables for the applicable design, corrosion and code requirements. Low-carbon 19Cr-9Ni consumables are commonly used. |
| Post-weld condition | Weld heat tint and adjacent chromium-depleted oxide can reduce localized corrosion resistance. | Remove unacceptable oxide and contamination by a validated mechanical or chemical cleaning process, especially for wetted or hygienic service. |
| Cold-worked components | Cold work raises strength, hardness and magnetic permeability while reducing ductility. | Specify the required strength condition and forming history; do not apply solution-annealed properties to heavily cold-worked parts. |
| Fasteners and sliding contact | Austenitic stainless surfaces can gall under high contact pressure or poor lubrication. | Use appropriate thread geometry, lubrication, surface treatment or dissimilar compatible grades where galling risk is significant. |
The 0.07% maximum carbon limit is central to welding decisions. Many modern heats are produced at lower carbon levels and may be dual-certified as 1.4301/1.4307 when all requirements of both grades and the same product standard are met. Dual certification must appear on the inspection document; it must not be assumed from a low reported carbon result alone.
Specifying and purchasing 1.4301
A technically complete order should identify the applicable product standard and edition, grade name or number, product form, dimensions and tolerances, delivery condition or strength level, process route and surface finish. Requirements for edge condition, flatness, internal soundness, corrosion testing, impact testing, special chemistry, inspection and marking should be added where relevant.
| Check | Why it matters |
|---|---|
| Product standard | Chemistry alone does not establish the required mechanical properties, testing or manufacturing route. |
| Delivery condition and process route | Solution-annealed, cold-worked, bright, hot-rolled and cold-rolled products can behave very differently. |
| Thickness or diameter range | Proof strength, elongation, impact and hardness requirements can change with dimension. |
| Surface finish and prime surface | Finish affects appearance, cleanability, friction and corrosion performance. |
| Inspection document | Specify EN 10204 type 3.1 or 3.2 when traceable test results and independent validation are contractually required; do not rely on the default document. |
| Welded-service carbon requirement | Confirm whether 1.4301 is acceptable or whether 1.4307/304L or a stabilized grade is required. |
| Corrosion environment | Review chlorides, temperature, crevices, deposits, cleaning chemicals and residual stress. |
| Cross-standard substitution | Compare the complete specifications, not only the labels 304, S30400 and 1.4301. |
| Regulatory or code status | Food contact, drinking water, pressure equipment, structural use and hygienic applications can impose requirements beyond the material grade. |
For EN 10088-2 flat products, an order designation normally includes quantity, product form, dimensional standard and options, grade, treatment or cold-worked condition where applicable, process route, optional tests and the required EN 10204 inspection document.
Sources
- BS EN 10088-1:2023 — Stainless steels: List of stainless steelsBritish Standards Institution
- SIST EN 10088-1:2024 / EN 10088-1:2023 previewSlovenian Institute for Standardization / CEN
- BS EN 10088-2:2024 — Sheet, plate and strip for general purposesBritish Standards Institution
- EN 10088-2:2024 — Stainless steel sheet, plate and strip delivery conditionsCEN / iTeh Standards
- Ambient-temperature mechanical properties of austenitic stainless steel flat products to BS EN 10088-2British Stainless Steel Association
- BS EN 10088-3:2023 — Semi-finished products, bars, rods, wire, sections and bright productsBritish Standards Institution
- Ambient-temperature mechanical properties of austenitic stainless steel long products to BS EN 10088-3British Stainless Steel Association
- Working with Stainless SteelsInformationsstelle Edelstahl Rostfrei / Euro Inox
- Practical Guidelines for the Fabrication of Austenitic Stainless SteelsNickel Institute and International Molybdenum Association
- An introduction to the corrosion resistance of stainless steelsBritish Stainless Steel Association
- Comparison of 304 or 316 and 304L or 316L compositions and corrosion behaviorBritish Stainless Steel Association
- Effect of cold work and heat treatment on magnetic permeability of austenitic stainless steelsBritish Stainless Steel Association
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