Yield
S235 ~235 MPa; AHSS 600–1500+ MPa depending on dual-phase / martensitic grade.
Darker cells mean a higher score for this topic on that metric.
Strength88
Heat resistance72
Fire performance84
Insulation8
Workability80
Circularity64
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Quick answers
Is steel non-combustible?
As a metal it is Euroclass A1, but it loses yield in fire and usually needs protection for a rated duration.
Steel vs iron?
Steel is iron with controlled carbon (typically <2%) and alloys; cast iron has more carbon and a different solidification path.
Does steel insulate?
No. Thermal conductivity is tens of W/m·K. Insulation is a separate layer (mineral wool, boards, VIP).
Why does steel rust?
Iron oxidises in the presence of water and oxygen. Alloys, zinc, paint or concrete cover slow that.
Is stainless “stainless” forever?
No. Chlorides, crevices and wrong grades pit. 304 vs 316 is a chemistry choice, not a slogan.
Can steel be recycled endlessly?
Magnetically, yes as a family. Copper contamination and coatings constrain some high-spec loops.
heat 72 · fire 84
Numbers below are bands used by working engineers, not live quotes. Tensile note: grade-dependent.
Fire performance in this atlas is editorial. Real projects need the assembly report.
Mechanical
E-modulus
~200 GPa — stiffness barely changes with carbon; geometry does the rest.
Toughness
Charpy values collapse below the ductile-to-brittle transition in BCC grades.
Fatigue
Welds and inclusions dominate life; polished laboratory bars overstate real joints.
Hardness
Annealed mild steel ~120 HV; quenched tool steels exceed 60 HRC.
Thermal
Conductivity
~45–55 W/m·K for carbon steel — a heat path, not a blanket.
Expansion
~12 × 10⁻⁶ /K; fire design must allow for that growth.
Softening
Yield falls sharply above ~400–500 °C; unprotected steel buildings need fireproofing.
Melting band
Solidus depends on carbon; cast irons sit lower than low-carbon plate.
Specific heat
~490 J/kg·K; thermal mass matters in furnace walls and cookware.
Electrical
Resistivity
~0.15 µΩ·m for mild steel — worse than copper, used where strength wins.
Magnetism
Ferritic grades are ferromagnetic; austenitic stainless is not.
Eddy losses
Silicon steels (electrical steel) cut transformer core losses.
Fire
Euroclass
Bare structural steel is A1 (non-combustible) but loses strength in fire.
Protection
Intumescent paint, boards or spray mineral wool buy time to R30–R120.
ISO 834
Standard fire curves size protection thickness, not the steel chemistry.
Spark risk
Carbon steel tools can spark; some plants specify copper-beryllium or aluminium bronze instead.
If a salesperson quotes a single “safety score”, ask which standard, which thickness, which year.
Keep exploring
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Chromium passive films that keep kitchens, chemical plant and façades from rusting like carbon steel.
Overall 64