Cast iron
Gray Iron Class 30
Manufacturer or standards-body identification; product values do not apply to every form or condition.
Identity / state reference
What distinguishes this material
ASTM A48 Class 30 is a tensile-test class associated with a separately cast test bar; the casting wall and the agreed test-bar suffix remain essential.
- Designation in this reference
- ASTM A48 Class 30
- Forms covered by the sources
- Gray-iron castings; test coupon is not the casting’s full-section property map.
- States to distinguish or confirm
- Record as-cast or heat-treated delivery condition and the agreed matrix/hardness specification.
- Temperature and exposure
- No universal service-temperature limit or room-temperature property set is assigned. Use the cited product document and the purchase certificate.
Property evidence for a stated condition
No condition-specific numerical table is reproduced here
The linked sources establish the identity and the stated product/state scope. Obtain the row for your actual form, section, treatment and test conditions before adopting strength, hardness or a thermal limit.
Resolve these conditions next
- What product standard, edition and complete grade are on the material certificate?
- What product form, section size and delivery/heat-treatment condition will be machined?
- Which A/B/C/S test bar and controlling casting wall were agreed?
For machining, take the exact grade, supplied condition and measured hardness where applicable into the tool maker’s application data. A generic material-family speed is not a substitute for an operation and tool-specific recommendation.
Sources and what they establish
Reviewed 23 October 2026. A source’s publication date and the review date are different. The scope below identifies the fields checked.
ASTM A48/A48M-22 scope
General engineering gray castings; classification based on separately cast test-bar tensile tests, not every casting location.
ASTM A48/A48M-22 scope ↗Dandong Foundry gray-iron class and test-bar guide
Foundry lists A48 Classes 20/30/40/50 and test-bar suffixes; used for class identity only, not current normative acceptance values or overseas equivalents.
Dandong Foundry gray-iron class and test-bar guide ↗Source identity, a named product example and a supplied-batch certificate are different evidence. Cross-standard similarity does not approve substitution.
Corrections from the previous article
- Remove the internally inconsistent GG25/GJL250 and DIN-number equivalence; do not classify by an approximate cross-standard table.
- Withdraw the legacy generic hardness (187–241 HB) and tensile-strength (207 MPa (30 ksi)) pair: the old page does not establish a matching product, heat treatment, section and test source.
- Remove the unsupported cutting-speed table and machinability percentage; select tooling only after the actual material condition is known.
Related references
Other gray-iron classes
Compare the class designation and its specimen or casting basis. A class label does not establish every section property of a finished casting.
Distinguish cast-iron structures
Read the gray-versus-ductile distinction before comparing class and grade records.