Description

Seamless steel pipes are long, hollow carbon steel pipe without weld seams, renowned for their high strength, pressure resistance, corrosion resistance, and structural uniformity. They are classified by manufacturing process into hot-rolled seamless steel pipes and cold-drawn (rolled) seamless steel pipes, and by application and material into various types such as structural, fluid transport, boiler, petroleum cracking, and stainless steel.

Classification of Seamless Steel Pipes:

1. By Manufacturing Process: Hot-rolled seamless pipes (outer diameter 32–630 mm, wall thickness 2.5–75 mm), cold-drawn (rolled) seamless pipes (outer diameter 5–200 mm, wall thickness 0.5–21 mm, high precision, smooth surface), extruded pipes, and top-mounted pipes (less common);

2. By Cross-sectional Shape: Round pipes (mainstream), irregularly shaped pipes (square steel pipe, rectangular steel pipe, hexagonal steel pipe, elliptical, etc.);

3. By Material: Carbon steel seamless pipes, alloy structural steel seamless pipes, and stainless steel seamless pipes (austenitic/ferritic/martensitic, etc.);

Applications of Seamless Steel Pipes:

Seamless steel pipes are mainly used in four major areas: oil transportation, machinery manufacturing, boiler high-pressure pipelines, and construction engineering.

1. Fluid Transportation: Widely used for transporting oil, natural gas, coal gas, water, and certain solid materials. They are key materials for oil and gas extraction and transportation, such as oil gathering pipes within oil fields.

2. Structural Component Manufacturing: Due to its light weight and high strength, it is commonly used to make automobile drive shafts, bicycle frames, and steel scaffolding in construction.

3. Mechanical Parts: Widely used in manufacturing bearing rings, jack sleeves, and other ring-shaped parts, saving materials and processing time.

Special Applications:

1. High-Pressure and High-Temperature Environments: High-pressure pipeline systems in power plant boilers, nuclear power equipment, and chemical plants require heat-resistant alloy seamless pipes, such as high-pressure boiler tubes.

2. Corrosive Environments: In the chemical industry handling strong acids and alkalis, or in marine engineering, corrosion-resistant alloy seamless steel pipes are used to ensure long-term stability.

3. Geological and Military Applications: Used for special purposes such as oil and gas drilling pipes, gun barrels, and cannon barrels. Large-diameter pipes are also used in deep-sea pipeline projects.

Different applications correspond to different standards, such as structural use, fluid transportation, and boiler use. Material selection must be determined based on specific working conditions. Ordinary carbon steel is used for general pipelines, while alloy steel is used for high-pressure or mechanical parts.

Specifications of Seamless Steel Pipe:

SCH Strandard Wall Thickness
(MM)	SCH 10	SCH 20	SCH 40	SCH 60	SCH 80	SCH 100	SCH 160
	(mm)	(mm)	(mm)	(mm)	(mm)	(mm)	(mm)
1/4”	13.7			2.24		3.02
3/8”	17.1			2.31		3.2
1/2”	21.3	2.11		2.77		3.73		4.78
3/4″	26.7	2.11		2.87		3.91		5.56
1″	33.4	2.77		3.38		4.55		6.35
1-1/4″	42.2	2.77		3.56		4.85		6.35
1-1/2″	48.3	2.77		3.68		5.08		7.14
2″	60.3	2.77		3.91		5.54		8.74
2-1/2″	73	3.05		5.16		7.01		9.53
3″	88.9	3.05		5.49		7.62		11.13
3-1/2″	101.6	3.05		5.74		8.08
4″	114.3	3.05	4.50	6.02		8.56		13.49
5″	141.3	3.4		6.55		9.53		15.88
6″	168.3	3.4		7.11		10.97		18.26
8″	219.1	3.76	6.35	8.18	10.31	12.70	15.09	23.01
10″	273	4.19	6.35	9.27	12.7	15.09	18.26	28.58
12″	323.8	4.57	6.35	10.31	14.27	17.48	21.44	33.32
14″	355	6.35	7.92	11.13	15.09	19.05	23.83	36.71
16″	406	6.35	7.92	12.70	16.66	21.44	26.19	40.49
18″	457	6.35	7.92	14.27	19.05	23.83	29.36	46.24
20″	508	6.35	9.53	15.09	20.62	26.19	32.54	50.01
22″	559	6.35	9.53		22.23	28.58	34.93	54.98
24″	610	6.35	9.53	17.48	24.61	30.96	38.89	59.54
26″	660	7.92	12.7

Standards and Classifications

Product	Seamless Steel Tube
Seamless Pipe	China	GB/T8162/T8163 GB5310/6579/9948
	U.S.A.	ASTM A53, A106, A178, A179, A192, A210, A213, A333, A335, A283, A135, A214, 315, A500, A501, A519, A161, A334, API 5L, 5CT
	Japan	JIS G3452, G3454, G3456, G3457, G3458, G3460, 3461, 3462, 3464
	German	DIN 1626, 17175, 1629-4, 2448, 2391, 17200, SEW680
	Russia	GOST 8732, 8731, 3183
Material and Grade	China	10#, 20#, 16Mn, 20G, 15MoG, 15CrMo, 30CrMo,42Crmo, 27SiMn, 20CrMo
	U.S.A.	Gr. B, Gr.A, A179, A192, A-1, T11, T12, T22, P1, FP1, T5, 4140, 4130
	Japan	STPG38,STB30,STS38,STB33,STB42, STS49,STBA23,STPA25,STPA23
	German	ST33,ST37,ST35,ST35.8,ST45,ST52,15Mo3, 13CrMo44, 1.0309, 1.0305, 1.0405
	Russia	10, 20, 35, 45, 20X
Out Diameter		10-1000mm
Wall Thickness		1-80mm
Length		1-12m
Protection		Plastic caps
Packing terms		Labeled and bundled together with steel strip
Shipment terms		Containers or bundles by sea, one 20″ container can load about 20 tons
Shipment terms		(5.8meters long),one 40″ container can load about 23-25tons (less than 11.8meters long)
Quality Certificate		ISO, API, Mill Test Certificate
Surface Treatment		Black painting/varnished surface,anti-corrosion oil, galvanized or as per required by customer