Steel Q355NH
Q355NH is a 355 MPa-class weathering HSLA structural steel alloyed with copper, chromium, nickel and phosphorus, cross-listed with A588 and S355J2W.
Reference datasheet — Q355NH 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 HR condition
Q355NH tempers and conditions
Q355NH is supplied in 7 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HRDefault Hot rolled | Default stocked condition for weathering plate, coil and sections up to about 40 mm. | 380 | 540 | 26 | 165 HB | — |
Quality grade C | Standard toughness class for general outdoor structures in temperate climates. | 380 | 540 | 26 | 165 HB | 8 % IACS |
Quality grade D | For rolling stock and bridges exposed to cold winters. | 385 | 545 | 26 | 167 HB | 8 % IACS |
Normalized | Choose for thicker plate or where uniform fine grain and guaranteed low-temperature impact energy are required. | 390 | 545 | 28 | 160 HB | 8 % IACS |
Quality grade E | Lowest-temperature class, for northern-China railway wagons and cold-region structures. | 395 | 550 | 27 | 170 HB | 8 % IACS |
Thermomechanically controlled processed | Pick when a lower carbon equivalent and better field weldability are needed at the same strength level. | 410 | 550 | 27 | 170 HB | 8 % IACS |
Cold rolled | Thin gauge weathering strip for container panels and formed profiles; higher strength, reduced ductility. | 480 | 600 | 18 | 190 HB | 8 % IACS |
What is Q355NH?
Q355NH is a 355 MPa-class weathering HSLA structural steel alloyed with copper, chromium, nickel and phosphorus, cross-listed with A588 and S355J2W. It is used bare outdoors, where an adherent rust patina replaces paint, and is available hot-rolled, normalized, TMCP and cold-rolled in C, D and E impact grades, with typical values of 380 MPa yield, 540 MPa tensile, 26 % elongation and 165 HB (85 HRB). The patina depends on wet-dry cycling, so the grade is unsuitable for chloride-rich, buried or permanently wet service, and run-off stains adjacent concrete and aluminium. 09CuPCrNi is the choice when lower strength and better formability are acceptable. Q355NH 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). Q355NH has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 68% of steel grades. Elongation at break is 26% and the elastic modulus is 206 GPa (29.9 Msi).
What is Q355NH used for?
- railway wagons
- outdoor towers
- container structures
Advantages
- Good corrosion resistance — 32/100, better than 96% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
- Forms and bends easily — 65/100, 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
Q355NH properties
Typical room-temperature values for Q355NH-HR; bars are the position among steel grades.
Physical3
Q355NH 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
Q355NH has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 68% of steel grades. Elongation at break is 26% and the elastic modulus is 206 GPa (29.9 Msi).
Thermal6
Q355NH is rated for continuous service to 400°C (752 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
Q355NH conducts electricity at 8 % IACS, better than 55% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (32/100), better than 96% of steel grades.
Sustainability4
Producing a kilogram of Q355NH takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
Q355NH's machinability is good (55/100, better than 62% of steel grades); weldability very good (80/100); formability good (65/100).
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. Q355NH is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Q355NH
Is Q355NH easy to machine?
Machines like 1020-class HSLA at ~60 % of AISI 1212; use rigid setups and positive-rake carbide, expect stringy chips from low-sulfur heats.
Can Q355NH be welded?
Readily welded by SMAW/GMAW/SAW with low-hydrogen consumables; use weathering-matched filler (e.g. E8018-W2 / ER80S-Ni1 type) so the joint patinas with the base metal, preheat 50–100 °C above ~30 mm.
Can Q355NH be formed, bent or molded?
Cold bends to 2a–3a radius across the rolling direction; hot forming 900–1050 °C followed by normalizing restores toughness.
Q355NH 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 |
|---|---|---|
| Clower C (≤0.12) common in TMCP/weld-critical heats | ≤ 0.16 | 0.12 |
| Si | 0.1 – 0.5 | 0.35 |
| Mn | 0.5 – 1.5 | 1.1 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Cukey patina former | 0.2 – 0.55 | 0.35 |
| Cr | 0.3 – 1.25 | 0.6 |
| Ni | ≤ 0.65 | 0.25 |
| Mooptional | ≤ 0.3 | 0.05 |
| Nbmicro-alloy, optional | 0.02 – 0.06 | 0.03 |
| Vmicro-alloy, optional | 0.02 – 0.12 | 0.05 |
| Timicro-alloy, optional | 0.02 – 0.1 | 0.03 |
| Alacid-soluble Al minimum | ≥ 0.02 | 0.03 |
| Fe | balance |
What surface finishes work on Q355NH?
Usually left bare to develop the protective rust patina (allow free-draining details and shot-blast to remove mill scale); can be painted or hot-dip galvanized where run-off staining or chlorides are an issue.
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 Q355NH in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
How much does Q355NH cost?
Q355NH 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.
Q355NH — frequently asked
What is Q355NH used for?
Q355NH is typically used for railway wagons, outdoor towers and container structures. In short: weldable weathering structural steel; A588 / S355J2W equivalent; paint-free outdoor service.
What is the yield strength of Q355NH?
Q355NH has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — weaker than 68% of steel grades. Strength varies by condition: see the 7 listed tempers.
Is Q355NH easy to machine?
Reasonably — machinability is rated good (55/100, better than 62% of steel grades). Machines like 1020-class HSLA at ~60 % of AISI 1212; use rigid setups and positive-rake carbide, expect stringy chips from low-sulfur heats.
Can Q355NH be welded?
Yes — weldability is rated very good (80/100). Readily welded by SMAW/GMAW/SAW with low-hydrogen consumables; use weathering-matched filler (e.g. E8018-W2 / ER80S-Ni1 type) so the joint patinas with the base metal, preheat 50–100 °C above ~30 mm.
What surface finishes work on Q355NH?
Usually left bare to develop the protective rust patina (allow free-draining details and shot-blast to remove mill scale); can be painted or hot-dip galvanized where run-off staining or chlorides are an issue.
Can Q355NH be formed, bent or molded?
Cold bends to 2a–3a radius across the rolling direction; hot forming 900–1050 °C followed by normalizing restores toughness.
What is the maximum service temperature of Q355NH?
Q355NH 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.
What is the difference between Q355NH-HR and Q355NH-CR?
HR is the default condition — default stocked condition for weathering plate, coil and sections up to about 40 mm. CR: thin gauge weathering strip for container panels and formed profiles; higher strength, reduced ductility. Yield strength is 380 MPa in HR versus 480 MPa in CR.
How much does Q355NH cost?
Q355NH 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
- GB/T 4171 Atmospheric corrosion resisting structural steel — SAC (China) (2008)
- ASTM A588/A588M High-Strength Low-Alloy Structural Steel with Atmospheric Corrosion Resistance — ASTM (2019)
- EN 10025-5 Structural steels with improved atmospheric corrosion resistance (S355J2W) — CEN (2019)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.13 — Corrosion — ASM International (2005)
- Mysteel / SMM — Mysteel (2025)
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.