|
The pipes
shall be well finished, cleaned free from harmful defects.
They shall be reasonably straight, smooth, cylindrical
and subject to the following tolerances.
Pipes manufacturer shall explore a sufficient number of
visual inspections to provide reasonable assurance that they
have been properly evaluated.
(i)
Permissible variation in outside diameter.
For
all grades except X20CrMoV121
|
Hot
finished and Cold finished seamless pipes
|
|
Outside
diameter (mm)
|
Permissible
variations (mm)
|
|
Over
|
Under
|
|
10.3
to 48.3 incl.
|
0.40
|
0.40
|
|
Over
48.3 to 114.3 incl.
|
0.79
|
0.79
|
|
Over
114.3 to 219.1 incl.
|
1.58
|
0.79
|
|
Over
219.1 to 300 incl.
|
2.38
|
0.79
|
|
Over
300.
|
1%
|
1%
|
| |
|
|
|
For Grade X20CrMoV121
|
Outside
diameter (mm)
|
Permissible
variations (mm)
|
|
Over
|
Under
|
|
|
100
and under
|
0.75%
|
0.75%
|
|
|
Over
100 to 320 incl.
|
0.90%
|
0.90%
|
|
Over
320
|
1.00%
|
1.00%
|
| |
|
|
|
|
|
(ii)
Permissible variations in wall thickness :
For
all grades, except X20CrMoV121
The
minimum wall thickness at any point shall not be more than
12.5% under the nominal wall thickness specified
For
grade X20CrMoV121
|
Outside
diameter (mm)
|
Permissible
variation %
|
|
Over
|
Under
|
|
100 and
under
|
12.5
|
10
|
|
Over 100
to 320 incl.
|
12.5
|
12.5
|
|
Over 320
|
15.0
|
12.5
|
(iii) Permissible variation
in length :
Seamless
Hot finished and Cold finished pipes can be ordered in
specified length or in random length.
If ordered in specified length, the tolerance shall be
as follows :
For hot finished and cold finished pipes
|
Grade
|
Length
(m)
|
Permissible
variation in (mm)
Over
Under
|
|
All grades except
X20CrMoV121
|
All
length
|
6
0
|
|
For
grade
X20CrMoV121
|
6
and under
Over
6 to 12 incl.
|
10
0
15
0
|
|
