X2CrNi18-9
1.4307
Low-carbon chromium-nickel austenitic stainless steel · EN 10088-1:2023 — list, chemical composition and reference physical properties · EN 10088-2:2024 — sheet, plate and strip for general corrosion-resistant applications · EN 10088-3:2023 — semi-finished products, bars, rod, wire, sections and bright products for general corrosion-resistant applications
X2CrNi18-9 / 1.4307 is the principal low-carbon European 18Cr-9Ni austenitic stainless grade commonly associated with Type 304L. Its maximum 0.030% carbon content makes it resistant to weld-related sensitization under normal fabrication conditions, while retaining good formability, toughness and general corrosion resistance. It is not molybdenum alloyed, so the low carbon content should not be mistaken for improved resistance to chloride pitting, crevice corrosion or chloride stress-corrosion cracking. Mechanical and even some chemical requirements depend on the applicable EN 10088 product part, product form, thickness and delivery condition.
- C ≤ 0.030%Defining feature · Reduces chromium-carbide precipitation and intergranular-corrosion risk after normal welding.
- 18% Cr, 9% Ni; no specified Mo additionNominal alloy system · Good general-purpose corrosion resistance, but limited localized-corrosion resistance in aggressive chloride service.
- Rp0.2 ≥ 200–220 MPa in the solution-annealed conditionFlat-product strength · Exact minimum depends on cold-rolled strip, hot-rolled strip or plate.
- Rp0.2 ≥ 175 MPa; Rm 500–700 MPaLong-product strength · General solution-annealed long-product requirements up to 250 mm; bright products and other conditions have separate tables.
- Readily weldableWelding · Low carbon controls sensitization; weld heat tint and surface contamination still require appropriate treatment.
- Not hardenable by heat treatmentHeat treatment response · Strength can be increased substantially by cold working, which changes ductility and magnetic response.
Overview
- Designation system
- EN steel name and European steel number
- Product forms
- Cold-rolled strip and sheet, Hot-rolled strip, Hot-rolled plate, Semi-finished products, Bars and rods, Wire rod and drawn wire, Sections, Bright products
- Condition
- Solution annealed (+AT), Product-specific mill finishes and process routes under EN 10088-2 or EN 10088-3, Cold-worked strength levels where expressly specified by the applicable product standard
- Density
- 7.9 g/cm³ (Reference physical value from EN 10088-1; not a product acceptance tolerance.)
Designation and scope of the grade
The name X2CrNi18-9 follows the EN chemical-composition designation system: “X” identifies a high-alloy steel, “2” indicates approximately 0.02% nominal carbon, and “CrNi18-9” identifies the principal chromium and nickel contents. The corresponding European material number is 1.4307. The material is an austenitic corrosion-resistant stainless steel and is not a proprietary alloy.
EN 10088-1 identifies and classifies the steel, but it is not by itself a complete purchasing specification. EN 10088-2 governs general-purpose flat products, while EN 10088-3 governs general-purpose long and semi-finished products. Structural, pressure, tube, forging, wire or cold-heading applications may require a different product standard even though the steel number remains 1.4307.
A certificate stating only “304L” does not establish conformity with EN 10088. An EN order should identify 1.4307 and the applicable product standard, condition, dimensions, finish and inspection requirements.
Chemical composition and product-form distinction
| Element | EN 10088-1:2023 grade listing / EN 10088-2:2024 flat products | EN 10088-3:2023 long products |
|---|---|---|
| C | ≤ 0.030 | ≤ 0.030 |
| Si | ≤ 1.00 | ≤ 1.00 |
| Mn | ≤ 2.00 | ≤ 2.00 |
| P | ≤ 0.045 | ≤ 0.045 |
| S | ≤ 0.015 | ≤ 0.030 |
| Cr | 17.5–19.5 | 17.5–19.5 |
| Ni | 8.0–10.5 | 8.0–10.5 |
| N | ≤ 0.10 | ≤ 0.10 |
The applicable product standard controls. Do not apply the long-product sulfur limit to flat product ordered under EN 10088-2. Product analysis tolerances and restrictions on intentional additions are specified separately in the standards.
The low carbon limit is the metallurgical distinction that matters most. During welding or other thermal exposure, carbon can combine with chromium at austenite grain boundaries. Limiting carbon reduces chromium-carbide precipitation and therefore reduces susceptibility to intergranular attack. This advantage does not materially increase pitting resistance because the grade contains no intentional molybdenum addition.
Delivery condition and mechanical properties
The normal reference condition is solution annealed. EN 10088 gives a solution-annealing range of 1000–1100 °C followed by sufficiently rapid cooling, typically water or air depending on product geometry. The objective is to dissolve detrimental carbide precipitation and restore a homogeneous austenitic structure. This treatment does not harden the steel.
| Product form | Maximum thickness | Rp0.2 min. | Rp1.0 min. | Rm | Elongation min. | ISO-V impact energy |
|---|---|---|---|---|---|---|
| C — cold-rolled strip | 8 mm | 220 MPa | 250 MPa | 520–700 MPa | 45% | Not specified in this row |
| H — hot-rolled strip | 13.5 mm | 200 MPa | 240 MPa | 500–700 MPa | 45% | 100 J longitudinal / 60 J transverse where the standard's impact-test applicability is met |
| P — hot-rolled plate | 75 mm | 200 MPa | 240 MPa | 500–700 MPa | 45% | 100 J longitudinal / 60 J transverse where the standard's impact-test applicability is met |
Values apply to the product forms, test directions, specimen definitions and thickness ranges specified by EN 10088-2. They must not be transferred automatically to tube, bar, forging or pressure-product specifications.
| Thickness or diameter | HBW max. | Rp0.2 min. | Rp1.0 min. | Rm | Elongation min. | ISO-V impact energy |
|---|---|---|---|---|---|---|
| ≤ 160 mm | 215 | 175 MPa | 210 MPa | 500–700 MPa | 45% longitudinal | 100 J longitudinal |
| > 160 to 250 mm | 215 | 175 MPa | 210 MPa | 500–700 MPa | 35% transverse | 60 J transverse |
This is the general solution-annealed long-product table. Bright bars, wire and products supplied in cold-worked conditions have separate requirements.
EN 10088-2:2024 and EN 10088-3:2023 include cold-worked strength conditions for 1.4307. When such a condition is ordered, its designated strength level and applicable process route replace the solution-annealed property set. Cold-worked material should never be accepted against annealed-property assumptions.
Like other austenitic stainless steels, 1.4307 has a rounded stress-strain curve rather than the distinct yield point typical of structural carbon steel. Proof strength is therefore used. The material combines relatively modest annealed proof strength with high ductility, strong strain hardening and useful toughness, including at low temperatures when the correct product specification and impact requirements are applied.
Reference physical characteristics
| Property | Reference value | Condition or range |
|---|---|---|
| Density | 7.9 kg/dm³ | Reference value |
| Elastic modulus | 200 GPa | 20 °C |
| Elastic modulus | 194 / 186 / 179 / 172 / 165 GPa | 100 / 200 / 300 / 400 / 500 °C |
| Mean thermal expansion coefficient | 16.0 × 10⁻⁶/K | 20–100 °C |
| Mean thermal expansion coefficient | 16.5 / 17.0 / 18.0 / 18.0 × 10⁻⁶/K | 20–200 / 300 / 400 / 500 °C |
| Thermal conductivity | 15 W/(m·K) | 20 °C reference value |
| Specific heat capacity | 500 J/(kg·K) | 20 °C reference value |
| Electrical resistivity | 0.73 Ω·mm²/m | 20 °C reference value |
These are reference physical values, not lot-by-lot acceptance requirements. Temperature-dependent design should use values and rules from the applicable design or construction standard.
The relatively high thermal expansion and low thermal conductivity compared with carbon steel influence welding distortion, thermal cycling and mixed-material joints. Fixtures, joint design and expansion allowances should account for these differences.
Corrosion behavior and service selection
In a clean, properly finished condition, 1.4307 offers good resistance in many atmospheric, food-processing, domestic, architectural and mildly corrosive process environments. The passive chromium-rich surface film is responsible for this behavior. Surface condition, fabrication cleanliness, deposits and geometry can be as important as bulk composition.
Its low carbon content provides resistance to intergranular corrosion in both the delivery and sensitized test conditions specified by EN 10088 for the relevant annealed products. This is particularly useful in welded fabrications that cannot be solution annealed after welding. Low carbon does not, however, protect against chloride pitting, crevice corrosion or chloride stress-corrosion cracking.
Because 1.4307 contains no intentional molybdenum, it is normally less resistant to chloride-induced localized corrosion than 1.4404 / 316L. Grade selection for water, chemical or outdoor service cannot be based on chloride concentration alone: temperature, pH, oxidants, crevice geometry, deposits, flow, surface finish, cleaning regime and chloride concentration at evaporative or splash locations all matter. Marine exposure, warm chloride solutions, stagnant crevices and evaporative concentration require particular caution.
There is no single universal maximum service temperature or chloride limit for 1.4307. Corrosion limits must be established for the actual environment; elevated-temperature mechanical or oxidation service may also require a different grade and specification.
Fabrication and welding
| Operation | What matters for 1.4307 |
|---|---|
| Cold forming | High ductility supports deep drawing, bending and forming, but pronounced strain hardening increases forming loads and springback as deformation progresses. |
| Machining | Less free-cutting than sulfur-alloyed stainless grades. Use rigid equipment, sharp tooling, positive cutting action and a feed that remains below the work-hardened surface layer. |
| Welding | Suitable for the usual fusion-welding processes. Matching low-carbon consumables are commonly classified as 19 9 L types under EN ISO 14343, subject to joint design and service requirements. |
| Post-weld treatment | Post-weld heat treatment is not normally required solely to prevent sensitization after ordinary welding. Unusual prolonged thermal exposure, pressure-code requirements or severe corrosion service require separate assessment. |
| Surface restoration | Remove weld heat tint, embedded iron and fabrication contamination by suitable mechanical or chemical cleaning. Pickling, passivation or electropolishing may be appropriate depending on finish and service. |
| Magnetic response | Normally has low magnetic permeability when solution annealed, but cold work and weld-metal ferrite can produce a measurable magnetic response. Do not specify it as universally non-magnetic. |
| Heat treatment | Cannot be strengthened by quench-and-temper treatment. Solution annealing restores ductility and corrosion condition; cold work is the principal strengthening mechanism. |
Carbon-steel tools, grinding debris, handling equipment and storage surfaces can contaminate stainless steel with free iron and cause rust staining. Dedicated or thoroughly cleaned tooling and segregation from carbon-steel fabrication are important where appearance, hygiene or corrosion performance matters.
Specifying and purchasing 1.4307
A technically complete order should identify the product standard rather than treating the grade number as a universal property specification. At minimum, state 1.4307 / X2CrNi18-9, the applicable EN product standard, product form and dimensions, delivery condition or process route, surface finish, dimensional-tolerance standard, quantity, inspection document and any supplementary testing.
| Item | Reason |
|---|---|
| Governing product standard | Controls chemistry, mechanical properties, test orientation, thickness limits and delivery condition. |
| Product form and thickness | Flat and long products have different property tables; even sulfur limits can differ. |
| Condition and strength level | Solution-annealed and cold-worked material cannot be represented by one common property set. |
| Surface finish | Affects appearance, cleanability, roughness and localized-corrosion behavior. |
| Inspection certificate | EN 10204 type 3.1 is commonly requested when traceability and reported test results are required, but it must be stated in the order. |
| Intergranular-corrosion testing | Specify the test method and acceptance requirement when project or service conditions demand verification. |
| Pressure or structural use | Use the applicable pressure-product or construction standard; general-purpose EN 10088-2 or EN 10088-3 compliance may not be sufficient. |
| Cross-standard substitution | Compare complete chemistry, mechanical properties, dimensions, manufacturing route, heat treatment, testing and certification—not merely the label “304L.” |
Dual certification, such as 1.4301/1.4307 or EN 1.4307 plus ASTM 304L, is valid only when the actual product meets every requirement of each cited grade and standard. The certificate should list each standard with its correct designation rather than using a combined informal name.
Sources
- DIN EN 10088-1:2024-04 — Stainless steels, Part 1: List of stainless steels; German adoption of EN 10088-1:2023DIN Media
- DIN EN 10088-2:2025-01 — Stainless steels, Part 2: Sheet, plate and strip; German adoption of EN 10088-2:2024DIN Media
- DIN EN 10088-3:2024-04 — Stainless steels, Part 3: Long and semi-finished products; German adoption of EN 10088-3:2023DIN Media
- Tables of Technical Properties of Stainless Steelsworldstainless
- Practical Guidelines for the Fabrication of Austenitic Stainless SteelsNickel Institute and IMOA
- Selection of Welding Consumables for Welding Stainless SteelsBritish Stainless Steel Association
- Dual (Multiple) Certification of Stainless Steel ProductsBritish Stainless Steel Association
- Comparison of 304 or 316 and 304L or 316L Type Compositions and Effect on Corrosion ResistanceBritish Stainless Steel Association
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