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(a) Flattening test.- (i) A section of the tube not less than 40 mm
length shall be flattened cold between parallel plates.
No cracks or breaks in the metal shall occur until the
distance between the plates is less than the given by the
following formula. Evidence
of lamination or burnt material or incomplete penetration of
the weld shall not develop during the testing.
( 1 + e ) t
H = ----------------
e + ( t /D )
Where
t =
Specified thickness of tube (in mm)
D = Specified outside diameter of tube (in mm)
e = Flattening test constant as given below :
0.10 for tube grade WC 1
0.07 for tube grades WC2 & WC3.
(ii)
The weld shall be placed 90 degree from the line of
direction of the applied force.
(iii)
Superficial rupture as a result of minor surface
imperfections shall not be cause for rejection.
(iv)
Flattening test carried out in accordance with any
other standard code may be accepted in which case the code
adopted shall be specified.
(b) Flaring Test.- A section of tube of length equal to 1.5 times
the outside diameter, but not less than 50 mm, shall stand
being flared with a tool having 60 or 45 degree included angle
until the tube at the mouth of the flare has expanded to the
percentage given below without cracking
_________________________________________________________________________
Tube
%
expansion in outside diameter D for a d/D of_______
Grade
0.6 and
Over 0.6 to
Over 0.8
under
0.8 including_____________________
WC 1
12
15
19
WC2
12
15
19
WC3
10
12
17
_________________________________________________________________
d = inside
diameter of tube.
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