What is grey cast iron EN-GJL-250 used for?

EN-GJL-250 (BS 1452 Grade 250) grey cast iron is used for machine beds, engine blocks, gearbox housings, brake components and vibration-damping structures where good compressive strength and castability are needed.

Can grey cast iron be machined?

Yes. Grey cast iron machines very well. The graphite flakes act as a lubricant, reducing tool wear and giving good surface finish. It is one of the easiest metals to machine on a lathe or mill.

Is grey cast iron weldable?

Grey cast iron can be welded but requires specialist techniques including pre-heating to 300–500°C and slow cooling to avoid cracking. Braze welding or arc welding with nickel electrodes is most common.

PS QA 013 — Grey Cast Iron Bar GREY CAST IRON BAR — MACHINING GRADE

EN-GJL-250

BS 1452 Grade 250

Grey Cast Iron Bar

Grey cast iron bar produced by casting and machining. Graphite flakes distributed through the microstructure give grey cast iron its characteristic grey fracture appearance and impart excellent machinability, good vibration damping and self-lubricating properties. EN-GJL-250 (BS 1452 Grade 250) is the most common machining grade, offering a good balance of tensile strength and machinability for bearing housings, slideways and machine components.

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Bar-end colour code

ORANGE

PS QA 013

Specifications & Equivalents

Grade Designations.

BS EN 1561:2011	EN-GJL-250 / EN-JL1040
BS 1452:1990 (withdrawn)	Grade 250
ASTM	A48 Class 40
DIN	GG-25 / 0.6025
JIS	FC250

Stock Range

Availability & Supply Condition.

Cast and machined rounds: 25–400mm diameter. Cut lengths available from stock.

Supply condition: Cast and centreless ground or turned to close diameter tolerance. Supplied in the as-cast condition.

Cut to length from 1 piece — −0/+2mm standard tolerance — 2–3 day turnaround — Cutting service details ›

Chemical Composition

Chemical Analysis.

Values shown as percentages by weight (% wt). Values are ranges unless stated as maxima.

Element	Typical Range (%)	Notes
Carbon (total)	3.00–3.50	Exists as graphite flakes
Silicon (Si)	1.70–2.50	Controls graphitisation
Manganese (Mn)	0.50–0.90
Phosphorus (P)	0.10–0.30
Sulphur (S)	0.05–0.15

For full chemical analysis with heat number, request an EN 10204 3.1 material test certificate when ordering — available on all alloy grades. Certificate types explained ›

Mechanical Properties

Mechanical Properties.

Values shown for standard supply condition. Properties vary by section size and heat treatment condition.

Designation	Tensile Strength (N/mm²)	Compressive Strength (N/mm²)	Hardness (HB)	Machinability
EN-GJL-250 / BS Gr.250	~250 (min)	~900	170–260	Excellent

Hardness values: see our hardness conversion table to convert between HRC, HB, HV and tensile strength.

Applications

Typical Applications.

Bearing housings and bushes
Slideways and guide surfaces — machine tools
Machine beds, frames and bases
Hydraulic and pneumatic valve bodies
Pump bodies and covers
Lathe chucks, faceplates and arbors

Benefits

Key Benefits.

Exceptional machinability — graphite lubricates the cut
Excellent vibration and noise damping
Good compressive strength for machine bases
Self-lubricating surface for bearings and slideways
Cost-effective for large machined components

Technical Notes

Remarks & Guidance.

Cannot be welded by conventional methods — highly susceptible to cracking under tensile or impact loading. Never specify for components subject to shock loading or significant tensile stress. Stress-relief annealing at 500–600°C can reduce residual casting stresses in critical components. Cannot be through-hardened in the same way as steel.