Key words: SA691
The sa691 (applicable to ASME Boiler and Pressure Vessel Code, see Volume II of SA-691) includes high temperature and high voltage welded carbon steel and alloy steel pipes. Heat treatment may not be required to obtain the required mechanical properties or to meet applicable specifications. Use the supplementary requirements provided when additional tests and checks are required.


The Sa691 has a nominal external diameter of 16 inches (405 mm) and a maximum wall thickness of 3 inches (75 mm). Other sizes of tubes can also be provided as long as they meet other requirements of this specification.