080M30
BS 970
080M30 is an engineering steel (Plain Carbon family) to BS 970. It has a specified 0.2 % proof stress of 280 MPa and a typical tensile strength of about 510 MPa, with a uniform elongation of 16 %. Nominal carbon content is around 0.27 %. For nonlinear FEA, a bilinear model uses E = 210 GPa up to yield and a tangent modulus of 1468 MPa above it. A plain-carbon steel: economical and predictable, strengthened by carbon content and heat treatment rather than alloying.
Bilinear material model — nonlinear FEA
Uniform elongation εu = 16.0% · conservative analysis limit ½εu = 8.0%
Bilinear (BISO) approximation. Elastic modulus E up to the 0.2% proof stress R_p0.2, then a single tangent slope Eₜ to the ultimate tensile strength: Eₜ = (Rₘ − R_p0.2) / (εu − R_p0.2/E − 0.002), where εu is the uniform elongation and Rₘ is a typical (nominal) UTS within the specified band. The half-εu figure is a conservative strain limit for the analysis. Treat these as guidance for first-pass models; for critical work use a measured true stress–strain curve for the actual product and condition.
Ratings — engineering judgement
Weldabilitymoderate
Medium carbon (~0.27%) — preheat and hydrogen-controlled consumables advisable, especially in thicker sections.
Machinabilitygood
Machines well, particularly in the normalised or pre-tempered condition.
Corrosion resistancepoor
No inherent corrosion resistance — protect by paint, galvanising or plating in exposed use.
Hardenabilitylow
Limited hardenability at low carbon — surface hardening is possible but through-hardening is not.
Toughnessmoderate
Adequate toughness for general use at ambient temperature.
Indicative ratings derived from composition and family — engineering guidance, not specification values.
Physical properties
| Density | 7850 | kg/m³ |
| Elastic modulus | 210 | GPa |
| Shear modulus | 80.8 | GPa |
| Poisson's ratio | 0.30 | |
| Thermal expansion | 12.0 | ×10⁻⁶/°C |
| Thermal conductivity | 48 | W/(m·K) |
| Specific heat | 470 | J/(kg·K) |
| Magnetic | Yes |
Typical values for plain carbon steel — use the mill certificate for the specific product.
Chemical composition (wt %)
Nominal composition per BS 970 for 080M30 — confirm exact limits against the standard.
Available forms
Common applications
- Shafts, axles and spindles
- Gears, pinions and couplings
- Connecting rods and levers
- General machined components and fasteners
History
The plain-carbon and low-alloy engineering steels are the backbone of general machinery — bar and forging stock selected on strength, hardenability and cost. In the UK they carry the enduring “EN” numbers of the wartime BS 970 schedule (now the 6-character 070M20-type codes).
- 1900Sheffield mills produce graded carbon and alloy engineering steels
- 1942BS 970 (War Emergency “EN” schedule) standardises UK engineering steels
- 1991EN 10083 harmonises the European quench-and-temper engineering grades
This profile is generated from the grade's core data and family. Composition is decoded from the designation where its naming system defines it; physical properties are family-typical and ratings are indicative. Confirm critical values against the governing standard or the mill certificate. Equivalents, historical designations and hand-written expert notes are added per grade over time.