Steel S355JR-M
Heat-treated state
EN S355JR · JIS SM490A · GB Q355B
M = thermomechanically controlled processed
Pick for lower carbon equivalent, best weldability with minimal preheat and good low-temperature toughness in plate.
Values for the M condition
Other S355JR tempers and conditions
S355JR is listed in 6 conditions; see the grade overview at S355JR.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
as-rolled, t = 40–80 mm | Thick as-rolled plate; use when heavy sections are needed, noting the standard's reduced minimum yield. | 350 | 520 | 24 | 155 HB | 9 % IACS |
Stress relieved | Use for welded fabrications and heavily machined frames where residual stress and distortion must be controlled. | 380 | 530 | 26 | 152 HB | 9 % IACS |
Normalized | Choose for fine, uniform grain, better through-thickness toughness and post-forming property recovery on heavy plate. | 395 | 540 | 27 | 155 HB | — |
ARDefault as-rolled (hot rolled), t ≤ 16 mm | Standard stocked hot-rolled plate, section and coil; cheapest route for general structures. | 400 | 550 | 25 | 160 HB | — |
MThis page Thermomechanically controlled processed | Pick for lower carbon equivalent, best weldability with minimal preheat and good low-temperature toughness in plate. | 425 | 520 | 28 | 165 HB | 9 % IACS |
Cold drawn | Cold-drawn bright bar for shafts and machined parts needing tight tolerance, better finish and higher strength. | 520 | 620 | 12 | 200 HB | 9 % IACS |
What is S355JR-M?
S355JR-M is S355JR heat treated to M — pick for lower carbon equivalent, best weldability with minimal preheat and good low-temperature toughness in plate. S355JR-M has a yield strength of 425 MPa (61.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 52% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi). S355JR-M 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). AR is the default condition FabDigit quotes; M is available on request or by drawing note.
Advantages
- Readily welded — 92/100, better than 93% of steel grades
- Ductile — tolerates forming and impact — 28%, better than 89% of steel grades
- Tough — resists crack growth — 130 MPa·√m (118.3 ksi·√in), better than 89% of steel grades
- Forms and bends easily — 68/100, better than 83% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
S355JR-M properties
Typical room-temperature values for S355JR-M; 23 are specific to this condition. Other listed values are S355JR reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S355JR-M 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
S355JR-M has a yield strength of 425 MPa (61.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 52% of steel grades. Elongation at break is 28% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S355JR-M 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
S355JR-M conducts electricity at 9 % IACS, better than 71% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of S355JR-M takes about 25 MJ of energy and emits 2.1 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 30%.
Manufacturability7
S355JR-M's machinability is good (58/100, better than 75% of steel grades); weldability excellent (92/100); formability good (68/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S355JR-M
Is S355JR easy to machine?
Machines like a medium-carbon steel — moderate tool wear, gummy chips in the as-rolled condition; use coated carbide, positive rake and generous coolant.
Can S355JR be welded?
Excellent weldability by all arc processes with CEV ≤ 0.45; preheat 100–150 °C only for thick sections or restraint, and use low-hydrogen consumables (E7018 / ER70S-6).
Can S355JR be formed, bent or molded?
Cold bends readily at 2–3 t inner radius across the rolling direction; hot forming 900–1050 °C followed by normalizing restores toughness.
What surface finishes work on S355JR?
No natural corrosion protection — shot-blast to Sa 2.5 then zinc-rich primer, epoxy paint, or hot-dip galvanize per EN ISO 1461.
S355JR 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 |
|---|---|---|
| Cmax 0.24 % for t ≤ 16 mm (EN 10025-2) | ≤ 0.24 | 0.18 |
| Si | ≤ 0.55 | 0.25 |
| Mn | ≤ 1.6 | 1.35 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Nnot applicable if sufficient N-binding elements present | ≤ 0.01 | 0.01 |
| Cu | ≤ 0.55 | 0.2 |
| CEVcarbon equivalent (IIW), t ≤ 30 mm | ≤ 0.45 | 0.42 |
| Fe | balance | — |
S355JR-M — frequently asked
What is S355JR-M used for?
S355JR-M is typically used for heavy structural steelwork, cranes, bridges, mobile equipment chassis and load-bearing frames. In short: weldable 355 MPa structural steel; stronger than S235/S275; widely stocked plate and section.
What is the yield strength of S355JR-M?
S355JR-M has a typical yield strength of 425 MPa (61.6 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 52% of steel grades. Strength varies by condition: see the 6 listed tempers.
Is S355JR-M easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machines like a medium-carbon steel — moderate tool wear, gummy chips in the as-rolled condition; use coated carbide, positive rake and generous coolant.
Can S355JR-M be welded?
Yes — weldability is rated excellent (92/100). Excellent weldability by all arc processes with CEV ≤ 0.45; preheat 100–150 °C only for thick sections or restraint, and use low-hydrogen consumables (E7018 / ER70S-6).
What surface finishes work on S355JR-M?
No natural corrosion protection — shot-blast to Sa 2.5 then zinc-rich primer, epoxy paint, or hot-dip galvanize per EN ISO 1461.
Can S355JR-M be formed, bent or molded?
Cold bends readily at 2–3 t inner radius across the rolling direction; hot forming 900–1050 °C followed by normalizing restores toughness.
What is the maximum service temperature of S355JR-M?
S355JR-M 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.
What is the difference between S355JR-AR and S355JR-CD?
AR is the default condition — standard stocked hot-rolled plate, section and coil; cheapest route for general structures. CD: cold-drawn bright bar for shafts and machined parts needing tight tolerance, better finish and higher strength. Yield strength is 400 MPa in AR versus 520 MPa in CD.
Sources
- EN 10025-2 Hot rolled products of structural steels — Non-alloy structural steels — CEN (2019)
- ASTM A572/A572M Grade 50 — ASTM International (2021)
- EN 1993-1-1 / EN 1993-1-2 Eurocode 3 design of steel structures — CEN (2005)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels — ASM International (1990)
- Structural steel S355 plate data sheets — SSAB / Dillinger / thyssenkrupp (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.