Permanent Steel Manufacturing Co., Ltd offers standard size seamless 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. The steel pipe sizes are as follows:

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)

Seamless Pipe Specification Chart

NOMINAL  PIPE  SIZE	OD(mm)	NOMINAL WALL THICKNESS
DN	NB(inch)	ASME	SCH10	SCH20	SCH30	STD	SCH40	SCH60	XS	SCH80	SCH100	SCH120	SCH140	SCH160	XXS
15	1/2"	21.3	2.11		2.41	2.77	2.77		3.73	3.73				4.78	7.47
20	3/4"	26.7	2.11		2.41	2.87	2.87		3.91	3.91				5.56	7.82
25	1"	33.4	2.77		2.9	3.38	3.38		4.55	4.55				6.35	9.09
32	1.1/4"	42.2	2.77		2.97	3.56	3.56		4.85	4.85				6.35	9.7
40	1.1/2"	48.3	2.77		3.18	3.68	3.68		5.08	5.08				7.14	10.15
50	2"	60.3	2.77		3.18	3.91	3.91		5.54	5.54				8.74	11.07
65	2.1/2"	73	3.05		4.78	5.16	5.16		7.01	7.01				9.53	14.02
80	3"	88.9	3.05		4.78	5.49	5.49		7.62	7.62				11.13	15.25
90	3.1/2"	101.6	3.05		4.78	5.74	5.74		8.08	8.08
100	4"	114.3	3.05		4.78	6.02	6.02		8.56	8.56		11.13		13.49	17.12
125	5"	141.3	3.4			6.55	6.55		9.53	9.53		12.7		15.88	19.05
150	6"	168.3	3.4			7.11	7.11		10.97	10.97		14.27		18.26	21.95
200	8"	219.1	3.76	6.35	7.04	8.18	8.18	10.31	12.7	12.7	15.09	18.26	20.62	23.01	22.23
250	10"	273	4.19	6.35	7.8	9.27	9.27	12.7	12.7	15.09	18.26	21.44	25.4	28.58	25.4
300	12"	323.8	4.57	6.35	8.38	9.53	10.31	14.27	12.7	17.48	21.44	25.4	28.58	33.32	25.4
350	14"	355.6	6.35	7.92	9.53	9.53	11.13	15.09	12.7	19.05	23.83	27.79	31.75	35.71
400	16"	406.4	6.35	7.92	9.53	9.53	12.7	16.66	12.7	21.44	26.19	30.96	36.53	40.19
450	18"	457.2	6.35	7.92	11.13	9.53	14.27	19.05	12.7	23.83	39.36	34.93	39.67	45.24
500	20"	508	6.35	9.53	12.7	9.53	15.09	20.62	12.7	26.19	32.54	38.1	44.45	50.01
550	22"	558.8	6.35	9.53	12.7	9.53		22.23	12.7	28.58	34.93	41.28	47.63	53.98
600	24"	609.6	6.35	9.53	14.27	9.53	17.48	24.61	12.7	30.96	38.89	46.02	52.37	59.54
650	26"	660.4	7.92	12.7		9.53			12.7
700	28"	711.2	7.92	12.7	15.88	9.53			12.7
750	30"	762	7.92	12.7	15.88	9.53			12.7
800	32"	812.8	7.92	12.7	15.88	9.53	17.48		12.7
850	34"	863.6	7.92	12.7	15.88	9.53	17.48		12.7
900	36"	914.4	7.92	12.7	15.88	9.53	19.05		12.7

Seamless Steel Pipe Specification Representation Method

	Illustrate	Example
Outer diameter (D)	Outer diameter of steel pipe, unit: mm	Φ48×4 indicates an outer diameter of 48mm.
Wall thickness (S)	Outer diameter of steel pipe, unit: mm	Φ48×4 indicates an outer diameter of 48mm.
Inner diameter (d)	Inner diameter, d = D - 2S	In the example above, the inner diameter is 40mm.
Material grade	Steel chemical composition labeling	20#, Q345B, 304, etc.

Commonly Used American Standards (ASTM/ASME) Specifications

ASTM A106/A53 Seamless Carbon Steel Pipe

Nominal Pipe Diameter NPS	Outer diameter OD (mm)	Standard weight, Sch40 wall thickness (mm)	Strengthen the wall thickness of Sch80 (mm)
1/8"	10.3	1.73	2.41
1/4"	13.7	2.24	3.02
3/8"	17.1	2.31	3.20
1/2"	21.3	2.77	3.73
3/4"	26.7	2.87	3.91
1"	33.4	3.38	4.55
1-1/4"	42.2	3.56	4.85
1-1/2"	48.3	3.68	5.08
2"	60.3	3.91	5.54
2-1/2"	73.0	5.16	7.01
3"	88.9	5.49	7.62
4"	114.3	6.02	8.56
6"	168.3	7.11	10.97
8"	219.1	8.18	12.70
10"	273.1	9.27	12.70
12"	323.9	9.53	12.70
14"~24"	355.6~609.6	9.53~12.70	12.70~22.23

Commonly Used European Standards (EN/DIN)

EN 10216 Series (Seamless Steel Tubes for Pressure Applications)

Standard number	Scope of application	Outer diameter range (mm)	Wall thickness range (mm)
EN 10216-1	Non-alloy steel pipes with normal temperature performance	10.2~711	1.6~100
EN 10216-2	High-temperature performance non-alloy and alloy steel pipes	10.2~711	1.6~100
EN 10216-3	Low-temperature performance alloy steel pipe	10.2~711	1.6~100
EN 10216-4	Low-temperature performance non-alloy and alloy steel pipes	10.2~711	1.6~100
EN 10216-5	stainless steel pipe	6~610	0.5~65

DIN 2448/DIN 2458 Standard Dimensions

Outer diameter series (mm)	Wall thickness series (mm)
10.2、13.5、17.2、21.3、26.9、33.7、42.4、48.3、60.3、76.1、88.9、114.3、139.7、168.3、219.1、273.0、323.9、355.6、406.4、457.0、508.0、610.0、711.0、813.0、914.0、1016.0	1.6、2.0、2.3、2.6、2.9、3.2、3.6、4.0、4.5、5.0、5.6、6.3、7.1、8.0、8.8、10.0、11.0、12.5、14.2、16.0、17.5、20.0、22.2、25.0、28.0、30.0、32.0、36.0、40.0、45.0、50.0、55.0、60.0、65.0、70.0、80.0、90.0、100.0

Factors Affecting the Dimensions of Seamless Steel Pipes

1. Rolling process parameters: The roll angle and rolling speed of the piercing machine directly affect the outer diameter accuracy of the steel pipe. The reduction amount and rolling passes during cold rolling determine the wall thickness deviation. Fluctuations in process parameters will lead to dimensional deviations.

2. Raw material quality: The diameter, roundness and material uniformity of the tube blank will be transmitted to the finished product. If the tube blank has ovality, it will easily lead to the outer diameter of the steel pipe being out of round.

3. Temperature control: Excessively high or uneven heating temperature will cause inconsistent deformation of the tube billet, and differences in cooling speed may cause dimensional shrinkage deviation, especially for high-precision cold-drawn tubes.

4. Equipment accuracy: The mechanical clearance and mold wear of equipment such as rolling mills and sizing mills will directly affect the diameter and wall thickness consistency of steel pipes. Old equipment is prone to aggravate dimensional fluctuations.

5. Subsequent processing: Improper operation of straightening, cutting and other processes may lead to straightness deviation or length size error of the steel pipe.

Different Industries Have Different Requirements for Seamless Steel Pipe Sizes

1. Oil and gas industry: large diameter (219-1422mm), thick wall (6-20mm) steel pipes, meet high pressure and long distance transportation, reduce joints.

2. Chemical industry: mostly medium diameter (25-377mm), wall thickness 5-16mm, stainless steel pipes are often used for corrosive media, and small diameter (10-50mm) can be used in low pressure scenes.

3. Power industry: boiler tube outer diameter 32-426mm, wall thickness 2.5-20mm, high pressure boiler requires thicker wall, in line with GB5310 standard.

4. Mechanical manufacturing: mainly precision tubes, outer diameter 6-200mm, wall thickness 0.5-10mm, dimensional tolerance requirements are strict (within ±0.1mm).

5. Construction industry: small diameter (20-50mm, wall thickness 1-3mm) for decoration, large diameter (159-630mm, wall thickness 5-15mm) for structural support.

Key Points for Selecting Seamless Pipe Sizes

1. Select size according to working conditions: Use general specifications for normal scenarios, prioritize thicker wall for high pressure and high temperature conditions, and select outer diameter as needed for fluid transportation.

2. Follow the corresponding standards: Domestic projects should give priority to national standards, while international projects should match the corresponding international standards. Mixing different standard sizes is prohibited.

3. Prioritize standard specifications: Prioritize the selection of readily available standard specifications to reduce procurement costs and delivery time; for special customized requirements, dimensions and tolerances must be clearly specified.

4. Balancing compatibility and precision: Matching the dimensions of compatible components to avoid connection problems; controlling dimensional tolerances and precision according to the application to avoid the misconception of blindly pursuing large diameters and thick walls.

Read more: Seamless Steel Pipe Size and Shape Quality Inspection