Introduction
Class 300 is a gray cast iron grade covered by ASTM A278/A278M. Typical applications include pressure-containing gray iron castings for service up to 650 F (350 C).
| Field | Value |
|---|---|
| Designation | Class 300 |
| Material Type | Cast Iron |
| Sub Type | Grey Cast Iron |
| Product Form | casting |
Manufacturing Process
Sand Casting
Shell Molding Casting
Lost Foam Casting
Equivalent Materials
N/A
Similar Materials
N/A
Reference Standards
| Standard | Standard Title | Edition | Specification | Identifier |
|---|---|---|---|---|
| ASTM A278/A278M | Standard Specification for Gray Iron Castings for Pressure-Containing Parts for Temperatures Up to 650 F (350 C) | 01 | Class 300 | — |
Related Casting Products
Physical Properties
N/A
Chemical Composition
| Element | ASTM A278/A278MEdition 01 · wt.%[1] |
|---|---|
| P | ≤ 0.25 |
| S | ≤ 0.12 |
Chemical requirements[2]
Notes
ASTM A278/A278M · Edition 01
[1] All properties in this column: Service above 230 C, up to 350 C
[2] Chemical composition: C + 0.3 * (Si + P) ≤ 3.8 wt.%
Heat Treatment
ASTM A278/A278M–01 · Stress relief for elevated-temperature service
| Step | Operation | Temperature | Cooling |
|---|---|---|---|
| 1 | Stress relief at 565-650 C; Table 2 | 565–650 °C; Holding time: 2–12 h[1] | — |
Notes
ASTM A278/A278M · Edition 01
[1] Stress relief for elevated-temperature service: Required for service above 230 C; up to standard service ceiling; Enter furnace not exceeding 400 F (200 C); heat/cool uniformly. For sections up to 1 in (25 mm), rates shall not exceed the printed 400 F/h (250 C/h); heavier-section rate per Holding time: and footnotes require section-dependent minimum 1 h/in or 1 h per 25 mm, not exceeding 12 h; retain independently printed unit-system rules.
Mechanical Properties
Core Mechanical Properties
ASTM A278/A278M — 01 · Table 4 — Normative
| Property | Value |
|---|---|
| Tensile Strength | ≥ 300 MPa |
- Separately cast test bar A, B, C or S selected for controlling section per Tables 1 and 5; Pressure-containing parts; up to 650 F / 350 C; unit systems as separately printed, not converted grades; Test bars shall represent the same lot. If heat treated, bars and castings are treated in the same furnace. Bar dimensions follow Table 1; purchaser selects bar via Table 5, otherwise manufacturer selects. The standard gives separate inch-pound and SI class tables; no identity equivalence is inferred between classes.
Welding Conditions
N/A
Applications
Grey cast iron ASTM A278/A278M Class 300 is used for pressure-containing gray iron castings for service up to 650 F (350 C). Other cast components used in this material family include pump bodies, valve bodies, covers, flanges and fittings. Typical settings include water, heating and industrial piping systems.
Finished-component pressure, temperature and fluid limits remain separate from the material grade and its standard-specific restrictions.
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