|
(a)
Material. - (i)
The tubes shall be seamless and manufactured from steel
produced by an open hearth or electric process or any of the
oxygen processes. The
steel shall be fully killed.
(ii)
The steel shall conform to the limits of chemical compositions
given in Table-1 and 2.
(iii)
The grain size of cold worked grade TP 321H shall be No.7 or
coarser.
(b)
Heat treatment. - (i)
All tubes of grades in Table-1, except T 91, 12X1Mo and
X20CrMoV121 shall be reheated and furnished in full annealed,
isothermal annealed or normalised and tempered condition.
If furnished in the normalised and tempered condition,
the minimum tempering temperature for Grades T1 and T11 shall
be 650 degree C and the minimum tempering temperature for
Grades T5, T9 and T22 shall be 675 Degree C.
(ii)
Tubing of Grades T1, T2 and T12 either hot finished or
cold drawn, may be given a final heat treatment at 650 degree
C to 730 degree C, instead of heat treatments specified in
sub-clause (i) above, at the option of the manufacture.
(iii)
Grade T91 shall be normalised at 1040 degree C minimum
and tempered at 730 degree C minimum as a final heat
treatment.
(iv)
Grade 12x1Mo shall be normalised at 950 - 980 degree C
and tempered at 720 - 750 degree C for a period of 1 to 3
hours.
(v)
Grade X20CrMoV121 shall be normalised at 1020 - 1070
degree C and tempered at 730 - 780 degree C for a period of 1
hour minimum.
(vi)
All austenitic tubes (Table 2) shall be furnished in
the heat treated condition.
The heat treatment procedure, except for the H grades
shall consist of heating the material to a minimum temperature
of 1040 degree C and quenching in water or rapidly cooling by
other means.
(vii)
All H grades shall be furnished in the solution treated
condition. If
cold working is involved in processing, the minimum solution
treating temperatures for grades TP321H and TP347H shall be
1100 degree C and for grades TP304H and TP316H shall be 1040
degree C. If the
P grade is hot rolled, the minimum solution treatment for
grades TP 321 H and TP 347 H shall be 1050 degree C and for
grades TP 304H and TP 316H shall be 1040 degree C.
(c) Workmanship and tolerance -
The tubes
shall be well finished, cleaned free from harmful defects.
They shall be reasonably straight, smooth, cylindrical
and subject to the following tolerances.
Finished tubes shall be reasonably straight and have
smooth ends free of burrs.
They shall have a workmanlike finish.
Surface imperfections like any discontinuity or
irregularity found in the tube may be removed by grinding,
provided that a smooth curved surface is maintained, and the
wall thickness is not decreased
to less than that permitted.
The outside diameter at the point of grinding may be
reduced by the amount so removed.
(i)
Permissible variation in outside diameter:
For
all grades except
12X1Mf
and X20CrMoV121
|
Outside
diameter (mm)
|
Permissible Variation (mm)
|
|
Over
|
Under
|
|
Hot
finished Seamless tubes
|
|
101.6
and under
|
0.4
|
0.8
|
|
Over
101.6 to 190.5 incl.
|
0.4
|
1.2
|
|
Over
190.5 to 228.6 incl.
|
0.4
|
1.6
|
|
Cold
finished Seamless tubes
|
|
Under
25.4
|
0.10
|
0.10
|
|
Over
25.4 to 38.1 incl.
|
0.15
|
0.15
|
|
Over
38.1 to 50.8 excl.
|
0.20
|
0.20
|
|
50.8
to 63.5 excl.
|
0.25
|
0.25
|
|
63.5
to 76.2 excl.
|
0.30
|
0.30
|
|
76.2
to 101.6 incl.
|
0.38
|
0.38
|
|
Over
101.6 to 190.5 incl.
|
0.38
|
0.64
|
|
Over
190.5 to 228.6 incl.
|
0.38
|
1.14
|
For
grade
12X1Mf
|
Outside
diameter (mm)
|
Permissible
Variation (mm)
|
|
Over
|
Under
|
|
Hot
finished and cold finished tubes
|
|
Under
30.0
|
0.30
|
0.30
|
|
30
to 50
|
0.40
|
0.40
|
|
Over
50.0
|
0.80%
|
0.80%
|
For
grade X20CrMoV121
|
Outside
diameter
|
Permissible
Variation (mm)
|
|
Over
|
Under
|
|
Hot
finished Seamless tubes
|
|
100
and under
|
0.75%
(0.5 mm min)
|
0.75%
(0.5 mm min)
|
|
Cold
finished seamless tubes
|
|
120
and under
|
0.60%
(0.25 mm min)
|
0.60%(0.25
mm min)
|
|
Over
120
|
0.75%
|
0.75%
|
(ii)
Permissible variation in Wall Thickness :
For
all grades except 12X1Mf
and X20CrMoV121
|
Outside
Diameter
(mm)
|
Wall
thickness %
|
|
|
2.4
and under
|
Over
2.4 to 3.8 incl.
|
Over
3.8 to 4.6 incl.
|
Over
4.6
|
|
Over
|
Under
|
Over
|
Under
|
Over
|
Under
|
Over
|
Under
|
|
Seamless
hot finished tubes
|
|
101.6
and Under
|
40
|
0
|
35
|
0
|
33
|
0
|
28
|
0
|
|
Over
101.6
|
0
|
0
|
35
|
0
|
33
|
0
|
28
|
0
|
|
Seamless
cold finished tubes
|
|
|
Over
|
Under
|
|
38.1
and under
|
20
|
0
|
|
Over
38.1
|
22
|
0
|
For
Grade
12X1Mf
|
Outside
Diameter (mm)
|
Permissible
variation %
|
|
Over
|
Under
|
|
Hot
Finished Seamless Tubes
|
|
108
and under
|
15
|
10
|
|
Over
108
|
20
|
5
|
|
Cold
Finished Seamless Tubes
|
|
All
sizes
|
10
|
10
|
For
Grade X20CrMoV121
|
Outside
diameter (mm)
|
Permissible
variation %
|
|
Over
|
Under
|
|
100
and under
|
12.5
|
10
|
(iii)
Permissible variation in length for exact length tubes.
For
all Grades except 12X1Mf
and X20CrMoV121
|
Method
of manufacture
|
Outside
diameter (mm)
|
Cut length (mm)
Over
Under
|
|
Seamless
Hot finished
|
All
sizes
|
5
0
|
|
Seamless
Cold finished
|
Under
50.8
|
3
0
|
|
50.8
Over
|
5
0
|
Note
: These permissible variations in lengths apply to cut lengths
upto and including 7.3 m.
For lengths over 7.3 m,
an additional over tolerance of 3 mm for each 3 m or
fraction thereof, shall be permissible, upto a maximum of 12
mm.
For
grade
12X1Mf
|
Out
side diameter (mm)
|
Length
of tubes (m)
|
Permissible
variation (mm)
Over
Under
|
|
Under
108
|
Under
9
|
15
0
|
|
9
to 12
|
35
0
|
|
108
and over
|
All
lengths
|
50
0
|
For
grade X20CrMoV121
|
Length
of tube (m)
|
Permissible variation
(mm)
Over
Under
|
|
6
and under
|
10
|
0
|
|
Over
6 to 12 incl.
|
15
|
0
|
(d) Test specimens. - (i)
Test specimens required for the flattening and expanding/
flaring test specified in regulations 49(a), 49 (b) and 49(c)
shall be taken from the ends of finished tubes prior to
upsetting, swaging, expanding or any other forming operations
or being cut to length. They
shall be smooth on the ends and free from burrs and flaws.
(ii)
If desirable and practicable, tensile test may be
carried out on full section of the
tubes upto the capacity of the testing machine.
For large size tubes, the tensile test specimen shall
consist of strip cut longitudinally from the tube and which is
not straightened within the gauge length further heat treated.
(iii)
If any test specimen shows flaws or defective machining it may
be discarded and another specimen substituted.
(iv)
All specimens shall be tested at room temperature.
(e)
Number of tests. - The tests
specified in regulations 49(a), 49(b) and 49(c) shall be made
on minimum 2 tubes for first 100 and 1 per 100 or part thereof
for tubes over 100 numbers.
TABLE
1
CHEMICAL
REQUIREMENTS FOR FERRITIC STEELS
|
Grade
|
Chemical
composition %
|
|
|
C
|
Mn
|
Si
|
S
|
P
|
Cr
|
Mo
|
V
|
Ni
|
Other
Elements
|
|
T1
|
0.10
0.20
|
0.30
0.80
|
0.10
0.50
|
0.025
max
|
0.025
max
|
-------
|
0.44
0.65
|
---
|
---
|
----
|
|
T2
|
0.10
0.20
|
0.30
0.61
|
0.10
0.30
|
0.025
max
|
0.025
max
|
0.50
0.81
|
0.44
0.65
|
----
|
---
|
-----
|
|
T5
|
0.15
max
|
0.30
0.60
|
0.50
max
|
0.025
max
|
0.025
max
|
4.00
6.00
|
0.45
0.65
|
----
|
----
|
-----
|
|
T9
|
0.15
max
|
0.30
0.60
|
0.25
1.00
|
0.025
max
|
0.025
max
|
8.00
10.0
|
0.90
1.10
|
----
|
----
|
-----
|
|
T11
|
0.05
0.15
|
0.30
0.60
|
0.50
1.00
|
0.025
max
|
0.025
max
|
1.00
1.50
|
0.44
0.65
|
----
|
----
|
-----
|
|
T12
|
0.05
0.15
|
0.30
0.61
|
0.50
max
|
0.025
max
|
0.025
max
|
0.80
1.25
|
0.44
0.65
|
----
|
---
|
-----
|
|
T22
|
0.05
0.15
|
0.30
0.60
|
0.50
max
|
0.025
max
|
0.025
max
|
1.90
2.60
|
0.87
1.13
|
----
|
----
|
-----
|
|
T91
|
0.08
0.12
|
0.30
0.60
|
0.20
0.50
|
0.010
max
|
0.020
max
|
8.00
9.50
|
0.85
1.05
|
0.18
0.25
|
----
|
Nb
= 0.06 -0.10
N
= 0.030 to 0.070
Ni
= 0.40 max
Al
= 0.04 max
|
|
12X1
Mf
|
0.10
0.15
|
0.40
0.70
|
0.17
0.37
|
0.025
max
|
0.025
max
|
0.90
1.20
|
0.25
0.35
|
0.15
0.30
|
0.25
max
|
Cu=0.20
Max
|
|
X20
CrMoV
121
|
0.17
0.23
|
1.00
max
|
0.50
max
|
0.030
max
|
0.03
max
|
10.0
12.5
|
0.80
1.20
|
0.25
0.35
|
0.30
0.80
|
|
TABLE
2
CHEMICAL
REQUIREMENTS OF AUSTENTIC STEEL
|
Grade
|
Chemical
composition %
|
|
|
C
|
Mn
|
Si
|
S
|
P
|
Cr
|
Mo
|
V
|
Ni
|
Other
Elements
|
|
TP304
|
0.08
max
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
18.0
20.0
|
----
|
----
|
8.00
11.0
|
----
|
|
TP304H
|
0.04
0.10
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
18.0
20.0
|
-----
|
----
|
8.00
11.0
|
-----
|
|
TP304L
|
0.035
max
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
18.0
20.0
|
-----
|
----
|
8.00
13.0
|
-----
|
|
TP310S
|
0.08
max
|
2.00
max
|
0.75
max
|
0.030
max
|
0.045
max
|
24.0
26.0
|
0.75
max
|
----
|
19.0
22.0
|
-----
|
|
TP316
|
0.08
max
|
2.00
max
|
0.75
max
|
0.030max
|
0.040
max
|
16.0
18.0
|
2.00
3.00
|
----
|
11.0
14.0
|
-----
|
|
TP316H
|
0.040
0.10
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
16.0
18.0
|
2.00
3.00
|
----
|
11.0
14.0
|
-----
|
|
TP316L
|
0.035
max
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
16.0
18.0
|
2.00
3.00
|
----
|
10.0
15.0
|
-----
|
|
TP321
|
0.08
max
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
17.0
20.0
|
----
|
----
|
9.00
13.0
|
Ti
= 5xC min
0.60
max
|
|
TP321H
|
0.04
0.10
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
17.0
20.0
|
----
|
----
|
9.00
13.0
|
Ti
= 4xC min
0.60
max
|
|
TP347
|
0.08
max
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
17.0
20.0
|
----
|
----
|
9.00
13.0
|
Nb
+ Ta = 10xC min
1.000
max
|
|
TP347H
|
0.04
0.10
|
2.00
max
|
0.75
max
|
0.030
max
|
0.040
max
|
17.0
20.0
|
----
|
-----
|
9.00
13.00
|
Nb
+ Ta = 8xC min
1.00
max"
|
|
