Seamless Steel Pipe Sizes and Weights

Hunan Standard Steel Co.,Ltd offers standard size seamless steel pipes primarily used in the oil and gas industry, automotive and engineering industries. This is the most common and widely used product and comes in different sizes and thicknesses. 

Seamless steel pipe sizes in mm:

Out diameter: 1/2 inch - 36 inch (21.3mm-914.4mm)
Thickness: 2.11mm-60mm ( SCH10, SCH20, SCH40, SCH80, STD, SCH120, SCH160, XXS)

General size table for Seamless steel pipes and Welded pipes in mm: 

Carbon seamless Steel Pipe & Tube Sizes and Weights:

Seamless Steel Pipe Sizes	Seamless Steel Pipe Schedule (INCH)
INCH	5S	5	10S	10	20	30	40	STD	60	80	100	120	140	160
1/8		0.035	0.049	0.049			0.068	0.068		0.095
1/4		0.049	0.065	0.065			0.2447	0.2447		0.3145
3/8		0.048	0.065	0.065			0.091	0.091		0.126
1/2	0.065	0.065	0.083	0.083			0.109	0.109		0.147				0.187
3/4	0.065	0.065	0.083	0.083			0.113	0.113		0.154				0.218
1	0.065	0.065	0.109	0.109			0.133	0.133		0.179				0.250
1 1/4	0.065	0.065	0.109	0.109			0.140	0.140		0.191				0.250
1 1/2	0.065	0.065	0.109	0.109			0.145	0.145		0.200				0.281
2	0.065	0.065	0.109	0.109			0.154	0.154		0.218				0.344
2 1/2	0.083	0.083	0.120	0.120			0.203	0.203		0.276				0.375
3	0.083	0.083	0.120	0.120			0.216	0.216		0.300				14.32
3 1/2	0.083	0.083	0.120	0.120			0.226	0.226		0.318
4	0.083	0.083	0.120	0.120			0.237	0.237		0.337		0.438		0.531
4 1/2								0.247
5	0.109	0.109	0.134	0.134			0.258	0.258		0.375		0.500		0.625
6	0.109	0.109	0.134	0.134			0.280	0.280		0.432		0.562		0.719
7								0.301
8	0.109	0.109	0.148	0.148	0.250	0.277	0.322	0.322		0.500	0.594	0.719	0.812	0.916
9
10	0.134	0.134	0.165	0.165	0.250	0.307	0.365	0.365		0.594	0.719	0.844	1.000	1.125
11
12	0.156	0.156	0.180	0.180	0.250	0.330	0.406	0.375	0.562	0.688	0.844	1.000	1.125	1.312
14	0.156		0.188	0.250	0.312	0.375	0.437	0.375	0.594	0.750	0.938	1.094	1.250	1.406
16	0.165		0.188	0.250	0.312	0.375	0.500	0.375	0.656	0.844	0.1031	1.219	1.438	1.593
18	0.165		0.188	0.250	0.312	0.437	0.562	0.375	0.750	0.938	1.156	1.375	1.562	1.781
20	0.188		0.218	0.250	0.375	0.500	0.594	0.375	0.812	1.031	1.281	1.500	1.750	1.968
22				0.250	0.375	0.500		0.375	0.875	1.125	1.357	1.625	1.875	2.215
24	0.218		0.250	0.250	0.375	0.562	0.687	0.375	0.969	1.219	1.531	1.812	2.062	2.343
30				0.312

Calculation of theoretical weight of seamless steel pipe:

The standard calculation formula for the theoretical weight of seamless steel pipe is:

W=0.02466×S×(D-S) (unit: kg/m)

Wherein, D represents the nominal outer diameter of the steel pipe (mm), and S represents the nominal wall thickness (mm). The coefficient 0.02466 is derived from the density of steel (7.85g/cm³) and unit conversion, and is applicable to common materials such as carbon steel and alloy steel. ‌‌

Calculation example:

Take a seamless steel pipe with an outer diameter of 60mm and a wall thickness of 4mm as an example:
W = 0.02466 × 4 × (60 - 4) = 5.52kg/m. ‌‌

‌Notes:
‌Deviation between theoretical value and actual value: Due to the dimensional error allowed by the production process (such as wall thickness deviation), the theoretical weight is only used as an estimated reference. ‌‌‌‌
‌Adjustment of special materials‌: Materials with large density differences such as stainless steel need to adjust the coefficient value, and the calculation formula needs to be multiplied by the ratio of the material density to 7.85. ‌‌

Key points for selecting seamless steel pipe sizes:

1. Wall thickness selection (working pressure)
High pressure/high temperature environment (such as 10MPa): Select Sch80, Sch160 (thickened wall).
Low pressure fluid (0.6MPa): Select Sch40 (standard wall thickness).

2. Matching of outer diameter and diameter
Pipe diameter (DN) ≠ outer diameter, need to be converted according to the standard (especially the difference between American standard NPS and national standard DN).
Flange and valve interface must be consistent with the outer diameter of the steel pipe, otherwise the diameter needs to be reduced.

3. Temperature and material selection
Carbon steel performance changes significantly at different temperatures, and the material needs to be matched:
-20℃~350℃: 20# steel, low carbon steel, good low temperature toughness.
350℃~550℃: 15CrMoG, alloy steel, resistant to high temperature oxidation.
≤-20℃: 16MnDG, low temperature steel, anti-brittle cracking.

Key points:
Carbon steel will graphitize when used for a long time above 400℃, and alloy steel (such as 12Cr1MoVG) must be selected.
Low temperature environment (such as LNG) requires Charpy impact test to verify toughness.

4. Outer diameter tolerance
Hot rolled tube: ±1%~1.5%.
Cold drawn tube: ±0.1%~0.5% (high precision).

5. Special needs
Corrosion resistance: select galvanized seamless tube or stainless steel composite tube.
Lightweight: consider thin-walled cold drawn tube (wall thickness ≤2mm).

Economic comparison:
The cost of galvanized carbon steel pipe is ＜50% of stainless steel pipe, but the life is shorter.
Chemical strong acid environment → directly select Hastelloy C276 for more reliability.

Common ASTM standards for seamless pipes include the following:

ASTM A53/A53M: This is a standard specification for pipe, steel, black and hot-dipped, zinc-coated, welded and seamless, used for general purposes, including galvanized and ungalvanized steel pipes.
ASTM A106/A106M: This is a standard specification for seamless carbon steel pipe for high-temperature or pressure service, typically used for applications above 350°C.
ASTM A312/A312M: This is a standard specification for seamless and welded austenitic stainless steel pipes, suitable for heavily cold-worked austenitic stainless steel tubes.
ASTM A269: This is a standard specification for seamless and welded austenitic stainless steel tubes for general corrosion-resistant and low- or high-temperature service applications.

ASTM A500/A500M: This is a standard specification for cold-formed welded and seamless carbon steel round, square, rectangular, or special shape structural tubes, used for welded, riveted, or bolted structures of bridges and buildings.
ASTM A209: This is a standard specification for seamless carbon steel and alloy steel tubes for use in boiler and superheater applications, suitable for high-temperature and pressure services.
ASTM A213/A213M: This is a standard specification for seamless ferritic and austenitic alloy steel tubes for boiler, superheater, and heat exchanger applications.
ASTM A335/A335M: This is a standard specification for seamless ferritic and austenitic alloy steel tubes for high-temperature service.

Read more: Schedule 40 vs Schedule 80 Pipe or China seamless steel pipe manufacturer list