ASTM (American Society for Testing and Materials)
A group of scientists and engineers formed the American Society for Testing and Materials in 1898.
ASTM International (ASTM), is an international standards organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services
ASTM predates other standards organizations such as (1901), DIN (1917) and AFNOR (1926), but differs from these in that it is not a national standards body.
MATERIALS- HEX NUTS
High /Low temperature service
MATERIALS- STUDBOLT/HEX NUTS