(i) Material.- Material, tube grade and chemical composition for
these tubes shall be in accordance with the appropriate clause
of Regulation 58.
shall be manufactured as prescribed in Regulation 58(b) and
subsequently cold drawn.
(iii) Tolerances.- Tolerance on thickness and outside diameter shall
be as follows :
Thickness - Plus
7.5% minus 7.5%
Plus 0.5% minus 0.5%
(With a minimum of 0.10 mm over and under).
on length shall be in accordance with Regulation 58(f).
(iv) Heat Treatment.- After final cold finishing the tubes shall be
heat treated as follows :
or sub-critically annealed#
2, WC 3
ends which are subjected to cold working operation shall be
suitably normalized or sub-critically annealed as above.
range 880 Deg.C to 940 Deg.C.
Temperature range 660 Deg.C to 720 Deg.C.
(v) Tests.- (a)Tensile Test. – This test shall be comply with the
provision of Regulation 60.
(b) Flattening test.–
This test shall comply with the provision of Regulation 59(a).
(c) Flaring test.– This
shall comply with the provision of Regulation 59(b).
(vi) Hydraulic test.- This shall comply with the provision of
(vii) Test specimens.-These shall comply with the provision of
(viii) Number of tests.- These shall comply with the provisions of