Gray Cast Iron Class 30 (ASTM A48)

Designations: A48 Class 30 · UNS F12101 · SAE J431 G3000ASTM A48 Class 30 is the general-purpose gray cast iron: strong enough for most housings and frames, easy to machine, and good at damping vibration. The class number is the minimum tensile strength in ksi, so Class 30 means 30 ksi. It is specified for pump and valve bodies, machine bases, brake components and gearbox housings. Kormax casts A48 Class 30 to order for customers in the United States and Canada.

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Chemical Composition

Gray Cast Iron Class 30 — chemical composition, % by weight
Element	Symbol	Range / limit %
Carbon	C	2.8–3.5
Silicon	Si	1.2–1.7
Manganese	Mn	0.8–1.2
Phosphorus	P	0.15 max
Sulfur	S	0.12 max
Chromium	Cr	0.05–0.45
Nickel	Ni	0.05–0.10
Molybdenum	Mo	0.10 max
Copper	Cu	0.15–0.40
Iron	Fe	Balance

Mechanical Properties

Gray Cast Iron Class 30 — mechanical properties
Property	Metric	Imperial
Tensile Strength, min	207 MPa	30 ksi
Hardness (Brinell), typical	187–241 HB	187–241 HB

ASTM A48 specifies minimum tensile strength only; the class number is that minimum in ksi. Hardness is typical (SAE J431 G3000 range) and varies with section size. Composition is Kormax typical foundry practice, not specified by ASTM A48.

Comparable and Related Specifications

The standards and grades below may have similar composition, properties or applications, but they should not be treated as direct equivalents without review. Chemistry, heat treatment, toughness requirements and testing provisions can differ between standards.