Structural steel · EN 10025-4

S420M

Full datasheet

Overview

S420M is a structural steel grade (EN 10025-4) used for buildings, frames, and general steelwork where weldability and cost matter.

Typical supply: Plate, sheet, sections, hollow sections, bars

Mechanical Properties

Young's modulus E210 GPa
Shear modulus G80.8 GPa
Yield / proof Re420 MPa
Ultimate Rm520 MPa
Poisson's ratio ν0.3

Thermal Properties

Thermal expansion α12 µm/(m·K)

For temperature derating, open Temperature Properties.

Physical Properties

Density ρ8e+3 kg/m³
Specific strength Sy/ρ5.35e+4 Pa·m³/kg
Specific stiffness E/ρ2.68e+7 Pa·m³/kg

Typical supply: Plate, sheet, sections, hollow sections, bars

Typical density ~7850 kg/m³. Supply form depends on grade (plate, shapes, HSS).

Applications

  • Building frames and bracing
  • Welded plate structures
  • Machine bases and supports
  • General structural fabrication

Advantages

  • Widely stocked and code-recognized for structural design
  • Good weldability for fabrication shops
  • Predictable strength and stiffness for steelwork

Limitations

  • Requires coating or paint for outdoor / wet service
  • Lower specific strength than aluminum or titanium
  • Not suitable as a corrosion-resistant alloy without protection

Standards

  • EN 10025-4

Equivalent Materials

Compare with these grades →

Electrical Properties

Not published for this grade.

Chemical Composition

Not published for this grade.

Machinability

Machinability index: 45 (AISI 1212 ≈ 100)

Good machinability in normalized / as-rolled condition; free-cutting grades preferred for high-volume turning.

Cost

Relative cost band: high

Commodity structural steel pricing in most markets.

Corrosion

Class: fair

Atmospheric corrosion like mild carbon steel — coat, galvanize, or paint for outdoor exposure.

  • Indoor dryfair
  • Outdoor paintedfair
  • Marine atmospherepoor

For allowance / life screening, open Corrosion Allowance.