I’ll provide you with the detailed chemical, physical, and mechanical properties of En1a steel as per BS970:1955 (British Standard). Please note that BS970:1955 has been superseded by newer standards, but the information remains relevant for understanding En1a steel’s properties.

Chemical Properties (as per BS970:1955):

1. Carbon (C): 0.07-0.15%
2. Silicon (Si): 0.10% max
3. Manganese (Mn): 0.80-1.20%
4. Phosphorus (P): 0.070% max
5. Sulfur (S): 0.20-0.30%

Physical Properties:

1. Density: approximately 7.85 g/cm³
2. Melting Point: around 1450°C (2642°F)
3. Thermal Conductivity: approximately 52 W/m·K
4. Electrical Resistivity: about 0.16 x 10⁻⁶ Ω·m
5. Magnetic Properties: Ferromagnetic

Mechanical Properties (in the as-supplied condition):

1. Tensile Strength: 370-440 MPa (54-64 ksi)
2. Yield Strength: 200-280 MPa (29-41 ksi)
3. Elongation: 20-30% (on 50mm gauge length)
4. Reduction of Area: Not specified in BS970:1955, but typically 40-50%
5. Hardness: 111-149 HB (Brinell)
6. Impact Strength: Not specified for this grade, as it’s primarily used for its machinability rather than toughness
7. Modulus of Elasticity: Approximately 190-210 GPa

Additional Properties:

1. Machinability: Excellent (rated at 100% in the machinability index, where 100% is the reference for free-cutting steels)
2. Weldability: Good, due to low carbon content
3. Cold Formability: Good
4. Hot Formability: Good

It’s important to note that:

1. The mechanical properties can vary slightly depending on the exact composition within the allowed range and the manufacturing process.
2. En1a is not typically heat-treated for strength improvement due to its low carbon content. However, it can be case-hardened if surface hardness is required.
3. The high sulphur content, which gives En1a its excellent machinability, also makes it less suitable for applications requiring high strength or toughness.
4. While BS970:1955 has been replaced by newer standards, the composition and properties of En1a have remained largely consistent, making this historical data still relevant for understanding the material’s characteristics.