Steel S355K2W
EN 1.8967 · also Corten B
S355K2W is a copper-nickel-chromium alloyed weathering structural steel and the highest-toughness class of the S355 weathering-steel family (1.8967, Corten B), guaranteeing higher impact energy at -20 °C than the J2W variant.
Reference datasheet — S355K2W is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the +AR condition
S355K2W tempers and conditions
S355K2W is supplied in 3 conditions, soft to hard. +AR is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+AR | Same steel supplied as heavy plate; specify when the design must use the reduced thickness-dependent yield values of EN 10025-5. | 355 | 510 | 25 | 150 HB | 8.5 % IACS |
Normalized | Choose for thick plate or where a fine, uniform grain and the most reliable -20 °C toughness are required (bridges, heavy welded structures). | 385 | 520 | 28 | 150 HB | — |
+ARDefault Hot rolled | Standard mill delivery condition for plate, coil and sections; use unless a normalized structure is specified. | 390 | 530 | 26 | 155 HB | — |
What is S355K2W?
S355K2W is a copper-nickel-chromium alloyed weathering structural steel and the highest-toughness class of the S355 weathering-steel family (1.8967, Corten B), guaranteeing higher impact energy at -20 °C than the J2W variant. Engineers specify it for exposed plate and section work where the self-forming patina replaces paint; default values are 390 MPa yield, 530 MPa tensile, 26 % elongation and about 155 HB (82 HRB), supplied as +AR, +N and thick +AR product. The patina needs wet-dry cycling and free drainage, so it is unsuitable for buried, submerged or chloride-washed positions. S355J2W is the obvious lower-toughness alternative. S355K2W has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F). S355K2W has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 64% of steel grades. Elongation at break is 26% and the elastic modulus is 210 GPa (30.5 Msi).
What is S355K2W used for?
- heavy exposed structural members
- bridges in demanding climates
- critical outdoor infrastructure
Advantages
- Good corrosion resistance — 32/100, better than 96% of steel grades
- Forms and bends easily — 70/100, better than 86% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Tough — resists crack growth — 120 MPa·√m (109.2 ksi·√in), better than 81% of steel grades
- Readily welded — 80/100, better than 79% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
S355K2W properties
Typical room-temperature values for S355K2W-+AR; bars are the position among steel grades.
Physical3
S355K2W has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,460°C (2,660 °F).
Mechanical16
S355K2W has a yield strength of 390 MPa (56.6 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 64% of steel grades. Elongation at break is 26% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S355K2W is rated for continuous service to 400°C (752 °F). It conducts heat at 45 W/m·K (26 BTU/hr·ft·°F), better than 66% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
S355K2W conducts electricity at 8.5 % IACS, better than 63% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (32/100), better than 96% of steel grades.
Sustainability4
Producing a kilogram of S355K2W takes about 26 MJ of energy and emits 2.2 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 30%.
Manufacturability7
S355K2W's machinability is good (55/100, better than 62% of steel grades); weldability very good (80/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. S355K2W is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S355K2W
Is S355K2W easy to machine?
Machines like a 355 MPa C-Mn steel but slightly gummier from Cu/Ni — use positive-rake carbide, moderate speed and generous feed to break chips.
Can S355K2W be welded?
Readily welded by SMAW/GMAW/SAW with weathering-grade consumables (e.g. Cu-Ni-Cr filler) so the weld patinas with the base metal; preheat 50–100 °C for thick or restrained joints and control hydrogen.
Can S355K2W be formed, bent or molded?
Good cold bending; use a bend radius of about 2t for t ≤ 16 mm across the grain, or hot form at 900–1050 °C followed by normalizing when toughness is critical.
S355K2W chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | ≤ 0.16 | 0.12 |
| Si | ≤ 0.5 | 0.35 |
| Mn | 0.5 – 1.5 | 1 |
| P0.035 max for long products | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.02 |
| Crpatina former | 0.4 – 0.8 | 0.6 |
| Cupatina former | 0.25 – 0.55 | 0.35 |
| Ni | ≤ 0.65 | 0.3 |
| Nbmicro-alloying, sum Nb+Ti+V limited | ≤ 0.06 | |
| V | ≤ 0.12 | |
| Ti | ≤ 0.05 | |
| Zroptional | ≤ 0.15 | |
| Fe | balance |
What surface finishes work on S355K2W?
Normally left bare so the protective patina forms (allow 1–3 years, provide drainage and avoid pockets that stay wet); if paint is required, blast to Sa 2½ and prime — no anodizing possible.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel S355K2W in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 1.8967
- Trade names
- Corten B
How much does S355K2W cost?
S355K2W is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
S355K2W — frequently asked
What is S355K2W used for?
S355K2W is typically used for heavy exposed structural members, bridges in demanding climates and critical outdoor infrastructure. In short: toughest S355 weathering class; paint-free exposed structures; guaranteed -20 °C impact energy.
What is the yield strength of S355K2W?
S355K2W has a typical yield strength of 390 MPa (56.6 ksi) and a tensile strength of 530 MPa (76.9 ksi) — weaker than 64% of steel grades. Strength varies by condition: see the 3 listed tempers.
Is S355K2W easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like a 355 MPa C-Mn steel but slightly gummier from Cu/Ni — use positive-rake carbide, moderate speed and generous feed to break chips.
Can S355K2W be welded?
Yes — weldability is rated very good (80/100). Readily welded by SMAW/GMAW/SAW with weathering-grade consumables (e.g. Cu-Ni-Cr filler) so the weld patinas with the base metal; preheat 50–100 °C for thick or restrained joints and control hydrogen.
What surface finishes work on S355K2W?
Normally left bare so the protective patina forms (allow 1–3 years, provide drainage and avoid pockets that stay wet); if paint is required, blast to Sa 2½ and prime — no anodizing possible.
Can S355K2W be formed, bent or molded?
Good cold bending; use a bend radius of about 2t for t ≤ 16 mm across the grain, or hot form at 900–1050 °C followed by normalizing when toughness is critical.
What is the maximum service temperature of S355K2W?
S355K2W is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does S355K2W cost?
S355K2W is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- EN 10025-5: Hot rolled products of structural steels — Technical delivery conditions for structural steels with improved atmospheric corrosion resistance — CEN (2019)
- EN 10027-2 / material number 1.8967 — CEN (2015)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASTM A588/A588M (comparable weathering steel) — ASTM (2019)
- Weathering steel plate datasheets (Corten B / S355J2W-K2W) — European plate mills (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.