The difference between erw and seamless pipe is mainly in the manufacturing procedure. The erw pipes are made through a process known as electric resistance welding while seamless pipes are mostly drawn from a single billet of raw material. The cost difference between seamless and erw pipes vary based on the production methods. The erw method involves welding but the seamless pipes require precision drawing. Depending on the size of the pipe, precision and material used to make the pipes, the procedures can become expensive over one other.
The seamless pipes have less absolute roughness and high surface smoothness. The seamless pipes are drawn to make the pipes so that there are not joints. The strength of the material is equivalent to the strength of the pipes for the drawn seamless pipes. The erw pipes are welded from a sheet, plate or coil to make the pipes. The welded joint is the weakest part of the pipe and it determines the overall strength of the pipe. Even though the material has a higher strength value, the welded joint limits the strength to the strength of the welded point. This is one of the reasons why seamless pipes are used in precision applications with high strength requirements.
The oil and gas sectors cannot afford to have a leakage or break in the middle of the operation. The consequence would be costlier and disastrous. The pipes need to have consistent strength allover and need to have high precision for better connections as well. The erw pipes do have higher absolute roughness, meaning the wall thickness of the pipes are not as uniform as in the seamless pipes and the edges of the pipes are not as fine as in the seamless pipes. This counts when connecting the edges together with fittings. When pipe fittings and pipes don’t attach together perfectly, the oil and gas applications become vulnerable. This is the main reason why the oil and gas industrial applications use the seamless pipes instead of the erw pipes.
The seamless and erw pipes both involve heating up the material. The seamless pipes can be produced through cold drawing or hot drawing as well. The cold drawing procedure happens at room temperature where deformations due to the softness of the heated metal are very less likely. The erw process on the other hand involves heating up the coil, strip, plate or sheet to desired temperatures for welding into a pipe. This can result in deformed thicknesses and edges along the pipe.
The seamless pipes will not have tracks or joints of welding even on the inside of the pipes. There can be a difference seen in the welded pipes that identify the welded joint. There are also markings that verify if the pipe is seamless or erw.
Different application types use the different types of pipes. Both the pipes come in various sizes but the erw pipes can be produced in larger diameters than the drawn seamless pipes.
| ID | NOMINAL PIPE SIZE (DN) |
OUT DIAMTER IN (MM) |
WEIGHT LB/FT (KG/M) |
WT IN (MM) |
|---|---|---|---|---|
| 5S | 1/8 (6) |
0.405 (10.3) |
... | *1 |
| 10S | 1/8 (6) |
0.405 (10.3) |
0.19 (0.28) |
0.049 (1.24) *1 |
| 40S | 1/8 (6) |
0.405 (10.3) |
0.24 (0.37) |
0.068 (1.73) |
| 80S | 1/8 (6) |
0.405 (10.3) |
0.31 (0.47) |
0.095 (2.41) |
| 5S | 1/4 (8) |
0.54 (13.7) |
... | *1 |
| 10S | 1/4 (8) |
0.54 (13.7) |
0.33 (0.49) |
0.065 (1.65) *1 |
| 40S | 1/4 (8) |
0.54 (13.7) |
0.43 (0.63) |
0.088 (2.24) |
| 80S | 1/4 (8) |
0.54 (13.7) |
0.54 (0.8) |
0.119 (3.02) |
| 5S | 3/8 (10) |
0.675 (17.1) |
... | *1 |
| 10S | 3/8 (10) |
0.675 (17.1) |
0.42 (0.63) |
0.065 (1.65) *1 |
| 40S | 3/8 (10) |
0.675 (17.1) |
0.57 (0.84) |
0.091 (2.31) |
| 80S | 3/8 (10) |
0.675 (17.1) |
0.74 (1.1) |
0.126 (3.2) |
| 5S | 1/2 (15) |
0.84 (21.3) |
0.54 (0.8) |
0.065 (1.65) *1 |
| 10S | 1/2 (15) |
0.84 (21.3) |
0.67 (1.0) |
0.083 (2.11) *1 |
| 40S | 1/2 (15) |
0.84 (21.3) |
0.85 (1.27) |
0.109 (2.77) |
| 80S | 1/2 (15) |
0.84 (21.3) |
1.09 (1.62) |
0.147 (3.73) |
| 5S | 3/4 (20) |
1.05 (26.7) |
0.68 (1.02) |
0.065 (1.65) *1 |
| 10S | 3/4 (20) |
1.05 (26.7) |
0.86 (1.28) |
0.083 (2.11) *1 |
| 40S | 3/4 (20) |
1.05 (26.7) |
1.13 (1.69) |
0.113 (2.87) |
| 80S | 3/4 (20) |
1.05 (26.7) |
1.48 (2.2) |
0.154 (3.91) |
| 5S | 1 (25) |
1.315 (33.4) |
0.87 (1.29) |
0.065 (1.65) *1 |
| 10S | 1 (25) |
1.315 (33.4) |
1.41 (2.09) |
0.109 (2.77) *1 |
| 40S | 1 (25) |
1.315 (33.4) |
1.68 (2.5) |
0.133 (3.38) |
| 80S | 1 (25) |
1.315 (33.4) |
2.17 (3.24) |
0.179 (4.55) |
| 5S | 1¼ (32) |
1.66 (42.2) |
1.11 (1.65) |
0.065 (1.65) *1 |
| 10S | 1¼ (32) |
1.66 (42.2) |
1.81 (2.69) |
0.109 (2.77) *1 |
| 40S | 1¼ (32) |
1.66 (42.2) |
2.27 (3.39) |
0.14 (3.56) |
| 80S | 1¼ (32) |
1.66 (42.2) |
3.0 (4.47) |
0.191 (4.85) |
| 5S | 1½ (40) |
1.9 (48.3) |
1.28 (1.9) |
0.065 (1.65) *1 |
| 10S | 1½ (40) |
1.9 (48.3) |
2.09 (3.11) |
0.109 (2.77) *1 |
| 40S | 1½ (40) |
1.9 (48.3) |
2.72 (4.05) |
0.145 (3.68) |
| 80S | 1½ (40) |
1.9 (48.3) |
3.63 (5.41) |
0.2 (5.08) |
| 5S | 2 (50) |
2.375 (60.3) |
1.61 (2.39) |
0.065 (1.65) *1 |
| 10S | 2 (50) |
2.375 (60.3) |
2.64 (3.93) |
0.109 (2.77) *1 |
| 40S | 2 (50) |
2.375 (60.3) |
3.66 (5.44) |
0.154 (3.91) |
| 80S | 2 (50) |
2.375 (60.3) |
5.03 (7.48) |
0.218 (5.54) |
| 5S | 2½ (65) |
2.875 (73) |
2.48 (3.69) |
0.083 (2.11) *1 |
| 10S | 2½ (65) |
2.875 (73) |
3.53 (5.26) |
0.12 (3.05) *1 |
| 40S | 2½ (65) |
2.875 (73) |
5.8 (8.63) |
0.203 (5.16) |
| 80S | 2½ (65) |
2.875 (73) |
7.67 (11.41) |
0.276 (7.01) |
| 5S | 3 (80) |
3.5 (88.9) |
3.03 (4.52) |
0.083 (2.11) *1 |
| 10S | 3 (80) |
3.5 (88.9) |
4.34 (6.46) |
0.12 (3.05) *1 |
| 40S | 3 (80) |
3.5 (88.9) |
7.58 (11.29) |
0.216 (5.49) |
| 80S | 3 (80) |
3.5 (88.9) |
10.26 (15.27) |
0.3 (7.62) |
| 5S | 3½ (90) |
4.0 (101.6) |
3.48 (5.18) |
0.083 (2.11) *1 |
| 10S | 3½ (90) |
4.0 (101.6) |
4.98 (7.41) |
0.12 (3.05) *1 |
| 40S | 3½ (90) |
4.0 (101.6) |
9.12 (13.57) |
0.226 (5.74) |
| 80S | 3½ (90) |
4.0 (101.6) |
12.52 (18.64) |
0.318 (8.08) |
| 5S | 4 (100) |
4.5 (114.3) |
3.92 (5.84) |
0.083 (2.11) *1 |
| 10S | 4 (100) |
4.5 (114.3) |
5.62 (8.37) |
0.12 (3.05) *1 |
| 40S | 4 (100) |
4.5 (114.3) |
10.8 (16.08) |
0.237 (6.02) |
| 80S | 4 (100) |
4.5 (114.3) |
15.0 (22.32) |
0.337 (8.56) |
| 5S | 5 (125) |
5.563 (141.3) |
6.36 (9.46) |
0.109 (2.77) *1 |
| 10S | 5 (125) |
5.563 (141.3) |
7.78 (11.56) |
0.134 (3.4) *1 |
| 40S | 5 (125) |
5.563 (141.3) |
14.63 (21.77) |
0.258 (6.55) |
| 80S | 5 (125) |
5.563 (141.3) |
20.8 (30.97) |
0.375 (9.53) |
| 5S | 6 (150) |
6.625 (168.3) |
7.59 (11.31) |
0.109 (2.77) *1 |
| 10S | 6 (150) |
6.625 (168.3) |
9.3 (13.83) |
0.134 (3.4) *1 |
| 40S | 6 (150) |
6.625 (168.3) |
18.99 (28.26) |
0.28 (7.11) |
| 80S | 6 (150) |
6.625 (168.3) |
28.6 (42.56) |
0.432 (10.97) |
| 5S | 8 (200) |
8.625 (219.1) |
9.92 (14.78) |
0.109 (2.77) *1 |
| 10S | 8 (200) |
8.625 (219.1) |
13.41 (19.97) |
0.148 (3.76) *1 |
| 40S | 8 (200) |
8.625 (219.1) |
28.58 (42.55) |
0.322 (8.18) |
| 80S | 8 (200) |
8.625 (219.1) |
43.43 (64.64) |
0.5 (12.7) |
| 5S | 10 (250) |
10.75 (273) |
15.21 (22.61) |
0.134 (3.4) *1 |
| 10S | 10 (250) |
10.75 (273) |
18.67 (27.78) |
0.165 (4.19) *1 |
| 40S | 10 (250) |
10.75 (273) |
40.52 (60.29) |
0.365 (9.27) |
| 80S | 10 (250) |
10.75 (273) |
54.79 (81.53) |
0.5 (12.7) *2 |
| 5S | 12 (300) |
12.75 (323.8) |
21.0 (31.24) |
0.156 (3.96) *1 |
| 10S | 12 (300) |
12.75 (323.8) |
24.19 (35.98) |
0.18 (4.57) *1 |
| 40S | 12 (300) |
12.75 (323.8) |
49.61 (73.86) |
0.375 (9.53) *2 |
| 80S | 12 (300) |
12.75 (323.8) |
65.48 (97.44) |
0.5 (12.7) *2 |
| 5S | 14 (350) |
14.0 (355.6) |
23.09 (34.34) |
0.156 (3.96) *1 |
| 10S | 14 (350) |
14.0 (355.6) |
27.76 (41.36) |
0.188 (4.78) Notes (1),(2) |
| 40S | 14 (350) |
14.0 (355.6) |
54.62 (81.33) |
0.375 (9.53) *2 |
| 80S | 14 (350) |
14.0 (355.6) |
72.16 (107.4) |
0.5 (12.7) *2 |
| 5S | 16 (400) |
16.0 (406.4) |
27.93 (41.56) |
0.165 (4.19) *1 |
| 10S | 16 (400) |
16.0 (406.4) |
31.78 (47.34) |
0.188 (4.78) Notes (1),(2) |
| 40S | 16 (400) |
16.0 (406.4) |
62.64 (93.27) |
0.375 (9.53) *2 |
| 80S | 16 (400) |
16.0 (406.4) |
82.85 (123.31) |
0.5 (12.7) *2 |
| 5S | 18 (450) |
18.0 (457) |
31.46 (46.79) |
0.165 (4.19) *1 |
| 10S | 18 (450) |
18.0 (457) |
35.8 (53.31) |
0.188 (4.78) Notes (1),(2) |
| 40S | 18 (450) |
18.0 (457) |
70.65 (...) |
0.375 (9.53) *2 |
| 80S | 18 (450) |
18.0 (457) |
93.54 (...) |
0.5 (12.7) *2 |
| 5S | 20 (500) |
20.0 (508) |
39.82 (59.32) |
0.188 (4.78) *1 |
| 10S | 20 (500) |
20.0 (508) |
46.1 (68.65) |
0.218 (5.54) Notes (1),(2) |
| 40S | 20 (500) |
20.0 (508) |
78.67 (117.15) |
0.375 (9.53) *2 |
| 80S | 20 (500) |
20.0 (508) |
104.23 (155.13) |
0.5 (12.7) *2 |
| 5S | 22 (550) |
22.0 (559) |
43.84 (65.33) |
0.188 (4.78) *1 |
| 10S | 22 (550) |
22.0 (559) |
50.76 (75.62) |
0.218 (5.54) Notes (1),(2) |
| 40S | 22 (550) |
22.0 (559) |
... | ... |
| 80S | 22 (550) |
22.0 (559) |
... | ... |
| 5S | 24 (600) |
24.0 (610) |
55.42 (82.58) |
0.218 (5.54) *1 |
| 10S | 24 (600) |
24.0 (610) |
63.47 (94.53) |
0.25 (6.35) *1 |
| 40S | 24 (600) |
24.0 (610) |
94.71 (141.12) |
0.375 (9.53) *2 |
| 80S | 24 (600) |
24.0 (610) |
125.61 (187.07) |
0.5 (12.7) *2 |
| 5S | 30 (750) |
30.0 (762) |
79.51 (118.34) |
0.25 (6.35) *1 |
| 10S | 30 (750) |
30.0 (762) |
99.02 (147.29) |
0.312 (7.92) *1 |
| 40S | 30 (750) |
30.0 (762) |
... | ... |
| 80S | 30 (750) |
30.0 (762) |
... | ... |
DN |
OD OF PIPE |
THICKNESS TABLE OF ERW PIPE |
|||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
B SERIES |
A SERIES |
SCH |
SCH |
SCH |
SCH |
LG |
STD |
SCH |
SCH |
SCH |
SCH |
XS |
SCH |
SCH |
SCH |
SCH |
|
32 |
38 |
42.4 |
3.2 |
2.8 |
1.6 |
- |
- |
- |
- |
- |
3.6 |
5.0 |
- |
- |
- |
6.3 |
- |
65 |
76 |
76.1 |
3.6 |
3.0 |
2.0 |
4.5 |
- |
- |
- |
- |
5.0 |
7.1 |
- |
- |
- |
10.0 |
- |
100 |
108 |
114.3 |
4.0 |
3.0 |
2.0 |
5.0 |
- |
- |
- |
- |
5.9 |
8.8 |
- |
11.0 |
- |
14.2 |
- |
200 |
219 |
219.1 |
6.3 |
4.0 |
2.9 |
6.3 |
- |
- |
7.1 |
10.0 |
8.0 |
12.5 |
- |
17.5 |
16.0 |
22.2 |
20.0 |
350 |
377 |
355.6 |
- |
5.0 |
4.0 |
8.0 |
8.0 |
10.0 |
10.0 |
16.0 |
11.0 |
20.0 |
13.0 |
28.0 |
25.8 |
36.0 |
32.0 |
