Steel S355K2
EN S355K2
S355K2 (S355K2G3, 1.0596) is a hot-rolled or normalized non-alloy structural steel in the EN 10025-2 family, in the same strength class as ASTM A572 Grade 50, Q355B and SM490B, with K2-level impact toughness guaranteed at −20 °C.
Reference datasheet — S355K2 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 +N condition
S355K2 tempers and conditions
S355K2 is supplied in 6 conditions, soft to hard. +N is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
+N | Very heavy normalized plate; reduced strength band (Rm 450–600 MPa) and lowest through-thickness toughness. | 340 | 500 | 23 | 146 HB | 10 % IACS |
+N | Thick normalized plate for heavy nodes and offshore sections; yield minimum 315–325 MPa. | 360 | 515 | 24 | 150 HB | 10 % IACS |
+N | Heavy plate band; yield minimum 335 MPa, slightly lower elongation requirement. | 375 | 525 | 25 | 153 HB | 10 % IACS |
+N | Medium plate thickness band; yield minimum steps down to 345 MPa. | 385 | 535 | 26 | 157 HB | 10 % IACS |
Hot rolled | Cheapest delivery condition, allowed by EN 10025-2 for K2 quality in thinner products where −20 °C impacts are still met. | 395 | 550 | 25 | 163 HB | — |
+NDefault Normalized | Standard stocked condition: normalized fine-grain plate/section with full −20 °C toughness and best weldability. | 400 | 545 | 26 | 160 HB | — |
Supply forms, finishes and certifications
Ways S355K2 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
+N+Z35 | +N with Z35 through-thickness quality | Certification |
What is S355K2?
S355K2 (S355K2G3, 1.0596) is a hot-rolled or normalized non-alloy structural steel in the EN 10025-2 family, in the same strength class as ASTM A572 Grade 50, Q355B and SM490B, with K2-level impact toughness guaranteed at −20 °C. Normalized bar, plate and section deliveries typically give 400 MPa yield, 545 MPa tensile, 26 % elongation, 160 HB (84 HRB) and service to 350 °C, with a weldability score of 90 for welded bridges and machine frames. It has no inherent corrosion resistance and loses strength above its 350 °C limit. Where the higher notch toughness of K2 is not required, S355J2 is the cheaper and more widely stocked choice. S355K2 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F). S355K2 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 60% of steel grades. Elongation at break is 26% and the elastic modulus is 210 GPa (30.5 Msi).
What is S355K2 used for?
- bridges
- heavy machinery frames
- cranes
- structural steelwork
- pressure-loaded structures
Advantages
- Readily welded — 90/100, better than 90% of steel grades
- High electrical conductivity — 10 % IACS, better than 83% of steel grades
- Forms and bends easily — 68/100, better than 83% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Tough — resists crack growth — 115 MPa·√m (104.7 ksi·√in), better than 77% of steel grades
Limitations
- Hard to polish — 40/100, worse than 96% of steel grades
S355K2 properties
Typical room-temperature values for S355K2-+N; bars are the position among steel grades.
Physical3
S355K2 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,425°C (2,597 °F).
Mechanical16
S355K2 has a yield strength of 400 MPa (58 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 60% of steel grades. Elongation at break is 26% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S355K2 is rated for continuous service to 350°C (662 °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
S355K2 conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (10/100), worse than 86% of steel grades.
Sustainability4
Producing a kilogram of S355K2 takes about 26 MJ of energy and emits 2.1 kg of CO₂ — less than 64% of steel grades. Typical recycled content is 25%.
Manufacturability7
S355K2's machinability is good (55/100, better than 62% of steel grades); weldability excellent (90/100); formability good (68/100).
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. S355K2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S355K2
Is S355K2 easy to machine?
Machines like ordinary C-Mn steel at ~60 % of AISI 1212; use rigid setups, moderate speeds and positive-rake carbide, expect stringy chips from low-sulphur heats.
Can S355K2 be welded?
Excellent weldability by SMAW/GMAW/SAW with CEV ≈0.43; use low-hydrogen consumables and preheat 75–150 °C for thick sections or high restraint per EN 1011-2.
Can S355K2 be formed, bent or molded?
Cold bends readily at 2t–3t inside radius transverse to rolling for t ≤ 16 mm; hot form at 900–1050 °C and re-normalize if formed below 750 °C.
S355K2 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≤0.20 % for t ≤ 30 mm; up to 0.22 % in thicker product (ladle analysis) | ≤ 0.2 | 0.17 |
| Si | ≤ 0.55 | 0.25 |
| Mn | ≤ 1.6 | 1.4 |
| P | ≤ 0.03 | 0.02 |
| S≤0.015 % typical for Z-quality plate | ≤ 0.03 | 0.01 |
| NLimit waived if sufficient N-binding elements (Al, Nb, V, Ti) are present | ≤ 0.01 | 0.01 |
| Cu | ≤ 0.55 | 0.2 |
| AlTotal Al for fine-grain / killed practice | ≥ 0.02 | 0.03 |
| Nb+V+TiMicro-alloying, sum limited; Nb ≤0.05, V ≤0.12, Ti ≤0.05 | ≤ 0.22 | 0.03 |
| CEVCarbon equivalent (IIW), t ≤ 30 mm; up to 0.49 for heavy plate | ≤ 0.47 | 0.43 |
| Fe | balance |
What surface finishes work on S355K2?
Cannot be anodized — protect by blast cleaning to Sa 2½ plus zinc-rich epoxy paint systems (ISO 12944), hot-dip galvanizing (watch Si content for coating thickness) or thermal-spray metallizing.
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 S355K2 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- S355K2G31.0596
- Similar grades
- A572 Grade 50Q355BSM490B
How much does S355K2 cost?
S355K2 is a budget-cost steel ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
S355K2 — frequently asked
What is S355K2 used for?
S355K2 is typically used for bridges, heavy machinery frames, cranes, structural steelwork and pressure-loaded structures. In short: best-welding S355 variant; −20 °C notch toughness; widely cross-referenced structural grade.
What is the yield strength of S355K2?
S355K2 has a typical yield strength of 400 MPa (58 ksi) and a tensile strength of 545 MPa (79 ksi) — weaker than 60% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is S355K2 easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like ordinary C-Mn steel at ~60 % of AISI 1212; use rigid setups, moderate speeds and positive-rake carbide, expect stringy chips from low-sulphur heats.
Can S355K2 be welded?
Yes — weldability is rated excellent (90/100). Excellent weldability by SMAW/GMAW/SAW with CEV ≈0.43; use low-hydrogen consumables and preheat 75–150 °C for thick sections or high restraint per EN 1011-2.
What surface finishes work on S355K2?
Cannot be anodized — protect by blast cleaning to Sa 2½ plus zinc-rich epoxy paint systems (ISO 12944), hot-dip galvanizing (watch Si content for coating thickness) or thermal-spray metallizing.
Can S355K2 be formed, bent or molded?
Cold bends readily at 2t–3t inside radius transverse to rolling for t ≤ 16 mm; hot form at 900–1050 °C and re-normalize if formed below 750 °C.
What is the maximum service temperature of S355K2?
S355K2 is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does S355K2 cost?
S355K2 is a budget-cost steel ($), 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 10025-2 Hot rolled products of structural steels — Non-alloy structural steels — CEN (2019)
- EN 10164 Steel products with improved deformation properties perpendicular to the surface — CEN (2018)
- ASTM A572/A572M Grade 50 High-Strength Low-Alloy Columbium-Vanadium Structural Steel — ASTM (2021)
- EN 1993-1-1 / EN 1993-1-2 Eurocode 3 design of steel structures (physical properties) — CEN (2005)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- EN 1011-2 Welding — Recommendations for arc welding of ferritic steels — CEN (2001)
- Structural steel plate S355K2+N datasheet — European plate mills (e.g. Dillinger / ArcelorMittal) (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.