ASTM A126-95e1 Standard Specification for Gray Iron Castings for Valves, Flanges, and Pipe Fittings
1.1 This specification covers three classes of gray iron for castings intended for use as valve pressure retaining parts, pipe fittings, and flanges.
1.2 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.
Note 1–The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.
Gray iron, or grey iron, is a type of cast iron that has a graphitic microstructure. It is named after the gray color of the fracture it forms, which is due to the presence of graphite. A Gray Iron Casting is a part that has been made by pouring molten metal into a temporary sand mold that has been imprinted with a pattern.
When were Gray Iron Castings invented?
The Chinese first produced Gray Iron Castings over 2,500 years ago. The Chinese applications for Gray Iron Castings included weaponry, stoves, common household goods, tools, building materials, and statuary. The earliest recognized western production of Gray Iron Castings dates back to 1450 AD in England. (Historical information provided the American Foundry Society.)
What benefits do Gray Iron Castings provide?
There are a number of important benefits that the use of Gray Iron for casting provides. Gray Iron Castings can be:
- Machined more easily
- Used for damping or controlling vibration in wide range of applications
- Formulated so their metallurgy meet specific applications’ requirements
- Used in applications that require dimensional stability
- Used in applications that require high strength to weight ratios
- Produced economically in high volumes using Disamatic equipment, and
- Tested for quality using non-destructive methods
- Designing a casting that are currently welded or assembled from several parts