ASTM A48 Class 30 Gray Iron

ASTM A48 / Class 30. A48 Class 30 is a general-purpose gray cast iron (~207 MPa / 30 ksi) prized for machinability, vibration damping and low cost in machine frames and housings.

Chemical composition (nominal wt %)

Element%
Carbon (C)3.1–3.4
Silicon (Si)2.0–2.4
Manganese (Mn)0.6–0.9
Sulfur (S)≤0.15
Phosphorus (P)≤0.15

Mechanical properties

PropertyValue
Tensile strength207 MPa (30 ksi) min
Yield strength— (brittle, no defined yield)
Elongation<1%
Hardness187–241 HB

Density: 7.15 g/cm³  ·  Heat treatment: Used as-cast; stress-relief anneal (540–565 °C) for dimensional stability.

Cross-standard equivalents

StandardEquivalent grade
EN / ISOEN-GJL-200
GBHT200
JISFC200
DIN (old)GG20

Equivalents by nominal class — confirm exact chemistry & spec for critical parts.

Typical applications

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FAQ

What is ASTM A48 Class 30 gray iron used for?

It is a general-purpose gray iron for machine frames, housings, manifolds and counterweights, chosen for good machinability, vibration damping and low cost.