Standard:
Api spec 5ct standard of american petroleum institute
Steel grade:
J55, k55, n80, l80, n80-1, n80q p110 etc
Diamensional tolerances:
Types of steel tubes outer diameterwall thickness
Cold-rolled tubes tube sizes(mm) tolerances(mm)tolerances(mm)
114.3a0.7912.5
114.30.5½1
Mechanical properties:
Standard codesmodels of steel tubestensite strength, mpayield strength, mpa elongation, hardness
Api spec 5ct j55517379½552check the table
K55517655
N80689552½758
L80(13cr)655552½655n241hb
P110862758½965.
