IIn the process heating like boiler/ chemical industries / paper, if the temperature exceeds 450 Deg c and with in 550 Deg c. then boiler quality alloy steel can be efficiently used for headers, risers, main steam lines etc. ASME specifies a set of Alloy Steel pipe specifications Which can be welded - Welding rod Specification is : E.8018.
It can be effectively used for pipe welding. root run can be tig welded using alloy steel tig wire Standard pipe schedules are available like sch 20 , sch 40 etc - 60.3 mm O.D x 3.63 mm thk pipe outer diameter and schedule is used in general practice. Such pipes have a negative tolerance which will be considered at the stage of designing [negative tolerance means variation in thickness up to a maximum of 12.5% to be checked from ASME SEC viii DIV-1] outer diameter ranges from 25 mm to 400 mm & thickness range from 2.53 mm to 25 mm
The Alloy Steel Pipe Specifications as per [ ASME SEC viii DIV-1 ] are
SA 335 P11
SA 335 P12
SA 335 P22
SA 335 P 5
SA 335 P 9