Welding Inspection & Metallurgy API ICP Self Study Notes

The type of notch and the impact test temperature are generally specified and
recorded, in addition to specimen size (if they are sub-size specimens,
smaller than 10 mm × 10 mm). Materials are often tested at various
temperatures to determine the ductile to brittle transition temperature. Many
codes and standards require impact testing at minimum design metal
temperatures based on service or location temperatures to assure that the
material has sufficient toughness to resist brittle fracture.