Steel S420MC-SR (Stress relieved)
Heat-treated state
EN S420MC
Only for dimensional stabilisation of heavily formed/welded assemblies; expect some loss of the TM strength.
Values for the SR condition
Other S420MC tempers and conditions
S420MC is listed in 4 conditions; see the grade overview at S420MC.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As-welded deposit | Design reference for welded S420MC structures — HAZ softening limits joint strength to roughly base-metal minimum. | 410 | 500 | 16 | 190 HB | 9 % IACS |
SRThis page Stress relieved | Only for dimensional stabilisation of heavily formed/welded assemblies; expect some loss of the TM strength. | 420 | 510 | 25 | 155 HB | 9.5 % IACS |
TMDefault Thermomechanically rolled, as-delivered | Standard mill condition for all S420MC — pick this for laser cutting, roll forming and cold bending of structural sheet. | 460 | 540 | 22 | 165 HB | 9.5 % IACS |
Pickled and oiled thermomechanically rolled strip | Choose when a scale-free, weldable and directly paintable surface is needed for stamped or roll-formed parts. | 460 | 540 | 23 | 163 HB | 9.5 % IACS |
What is S420MC-SR?
S420MC-SR is S420MC heat treated to SR — only for dimensional stabilisation of heavily formed/welded assemblies; expect some loss of the TM strength. S420MC-SR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 53% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi). S420MC-SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F). TM is the default condition FabDigit quotes; SR is available on request or by drawing note.
Advantages
- Forms and bends easily — 82/100, better than 94% of steel grades
- Readily welded — 90/100, better than 90% of steel grades
- Ductile — tolerates forming and impact — 25%, better than 77% of steel grades
- High electrical conductivity — 9.5 % IACS, better than 75% of steel grades
Limitations
- Hard to polish — 45/100, worse than 84% of steel grades
S420MC-SR properties
Typical room-temperature values for S420MC-SR; 22 are specific to this condition. Other listed values are S420MC reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
S420MC-SR has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,500°C (2,732 °F).
Mechanical16
S420MC-SR has a yield strength of 420 MPa (60.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 53% of steel grades. Elongation at break is 25% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
S420MC-SR 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
S420MC-SR conducts electricity at 9.5 % IACS, better than 75% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of S420MC-SR takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability7
S420MC-SR's machinability is good (58/100, better than 75% of steel grades); weldability excellent (90/100); formability very good (82/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S420MC-SR
Is S420MC easy to machine?
Machinable but tough and stringy — use sharp coated carbide, positive rake and generous feed; most parts are laser/plasma cut and punched rather than machined.
Can S420MC be welded?
Excellent weldability with low CEV; MAG/SAW/laser with matching or slightly under-matched wire, no preheat below ~10 mm, keep heat input moderate to limit HAZ softening.
Can S420MC be formed, bent or molded?
Designed for cold roll forming and press braking — bend transverse to rolling direction, min inner radius ≈ 1 × t; avoid hot forming above ~580 °C which erases TM strength.
What surface finishes work on S420MC?
No inherent corrosion resistance: phosphate + e-coat, powder paint, or hot-dip/electro zinc; pickled-and-oiled surface accepts paint directly after degreasing.
S420MC 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 |
|---|---|---|
| CEN 10149-2 max | ≤ 0.12 | 0.08 |
| Si | ≤ 0.5 | 0.2 |
| Mn | ≤ 1.6 | 1.3 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.02 | 0.01 |
| Altotal Al, min | ≥ 0.02 | 0.04 |
| Nbmicro-alloying | ≤ 0.09 | 0.04 |
| Vmicro-alloying | ≤ 0.2 | 0.03 |
| Timicro-alloying | ≤ 0.15 | 0.03 |
| Fe | balance | — |
S420MC-SR — frequently asked
What is S420MC-SR used for?
S420MC-SR is typically used for trailer chassis, agricultural machinery and crane arms. In short: mid-range MC strength; roll-forming friendly; trailer chassis standard.
What is the yield strength of S420MC-SR?
S420MC-SR has a typical yield strength of 420 MPa (60.9 ksi) and a tensile strength of 510 MPa (74 ksi) — weaker than 53% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is S420MC-SR easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machinable but tough and stringy — use sharp coated carbide, positive rake and generous feed; most parts are laser/plasma cut and punched rather than machined.
Can S420MC-SR be welded?
Yes — weldability is rated excellent (90/100). Excellent weldability with low CEV; MAG/SAW/laser with matching or slightly under-matched wire, no preheat below ~10 mm, keep heat input moderate to limit HAZ softening.
What surface finishes work on S420MC-SR?
No inherent corrosion resistance: phosphate + e-coat, powder paint, or hot-dip/electro zinc; pickled-and-oiled surface accepts paint directly after degreasing.
Can S420MC-SR be formed, bent or molded?
Designed for cold roll forming and press braking — bend transverse to rolling direction, min inner radius ≈ 1 × t; avoid hot forming above ~580 °C which erases TM strength.
What is the maximum service temperature of S420MC-SR?
S420MC-SR 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 S420MC-TM and S420MC-AW?
TM is the default condition — standard mill condition for all S420MC — pick this for laser cutting, roll forming and cold bending of structural sheet. AW: design reference for welded S420MC structures — HAZ softening limits joint strength to roughly base-metal minimum. Yield strength is 460 MPa in TM versus 410 MPa in AW.
Sources
- EN 10149-2 — Hot-rolled flat products of high yield strength steels for cold forming, thermomechanically rolled — CEN (2013)
- GB/T 1591 — High strength low alloy structural steels (Q420M) — SAC (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- Hot-rolled HSLA strip for cold forming — S420MC datasheet — SSAB / voestalpine / Baosteel (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.