Carbon Steel Seamless Pipe

Material:

Such as No. 20 carbon steel, No. 45 carbon steel, etc.

Dimensions:

Outer diameter range: Carbon steel seamless pipes have a wide range of outer diameters, from 10.3mm to 630mm1.

Wall thickness range: Wall thickness ranges from 1.5mm to 40mm1.

Specific size examples: For example, a steel pipe with an outer diameter of 32mm can have a wall thickness of 2.5mm; a steel pipe with an outer diameter of 108mm can have a wall thickness of 4mm1.

Description：

Carbon steel seamless steel pipe is the most common seamless steel pipe material, mainly composed of carbon, silicon, manganese, phosphorus, sulfur and other elements. According to its carbon content, it can be divided into low carbon steel, medium carbon steel and high carbon steel seamless steel pipe. Carbon steel seamless steel pipe has good strength and toughness, and is suitable for conveying fluids, manufacturing mechanical parts and structural parts, etc.

Carbon steel seamless steel pipes are mainly made of carbon steel. Carbon steel refers to an iron-carbon alloy with a carbon content of less than 2.11%. In addition to carbon, it usually contains a small amount of silicon, manganese, sulfur, phosphorus and other elements. Carbon steel seamless steel pipes have good machinability and welding properties and are widely used in general mechanical structures and construction fields.

Nominal outer diameter and wall thickness: For example, the nominal outer diameter of 20# seamless steel pipe is 88.9mm and the nominal wall thickness is 6.45mm. The allowable deviations of the outer diameter and wall thickness of the steel pipe are +0.50mm~0.20mm and +0.97mm~0.77mm respectively1.

‌Common specifications‌: The specifications of carbon steel seamless pipes include high-quality carbon steels such as 10, 20, 30, 35, 45, as well as low-alloy structural steels such as 16Mn, 5MnV or alloy steels such as 40Cr, 30CrMnSi, 45Mn2, 40MnB. These specifications of hot-rolled or cold-rolled seamless pipes are often used in fluid transportation pipelines2.

The production process of carbon steel seamless steel pipe includes:

‌Raw material preparation‌: Use steel ingots or solid tube billets.

‌Piercing‌: The tube billets are perforated by a piercing machine to form rough tubes.

‌Hot rolling, cold rolling or cold drawing‌: The rough tubes are formed by hot rolling, cold rolling or cold drawing.

‌Sizing and cooling‌: Cooling after sizing by a sizing machine.

‌Straightening and flaw detection‌: Internal flaw detection is performed after straightening to ensure that there are no cracks or bubbles.

‌Quality inspection and numbering‌: Numbering, specifications and production batch number marking are performed after quality inspection‌3.

Nominal diameter and wall thickness‌: The nominal diameter (DN) and outer diameter (mm) of carbon steel seamless steel pipes and the corresponding wall thickness (mm) are as follows:

DN10: outer diameter 17, wall thickness 2.5

DN20: outer diameter 27, wall thickness 3.0

DN25: outer diameter 34, wall thickness 3.5

DN32: outer diameter 42, wall thickness 3.5

DN40: outer diameter 48, wall thickness 4.0

DN50: outer diameter 60, wall thickness 4.5

DN65: outer diameter 76, wall thickness 5.5

DN80: outer diameter 89, wall thickness 6.0

DN100: outer diameter 114, wall thickness 6.0

DN125: outer diameter 140, wall thickness 6.5

DN150: outer diameter 168, wall thickness 7.0

DN200: outer diameter 219, wall thickness 8.0

DN250: outer diameter 2 73, wall thickness 9.0

DN300: outer diameter 323, wall thickness 10.0

DN350: outer diameter 377, wall thickness 11.0

DN400: outer diameter 426, wall thickness 12.5‌12

‌Theoretical mass‌: The theoretical mass (Kg/m) of carbon steel seamless pipes of different specifications are as follows:

DN10: 89

DN20: 117

DN25: 152

DN32: 190

DN40: 233

DN50: 275

DN65: 323

DN80: 375

DN100: 414

DN125: 465

DN150: 531

DN200: 617

DN250: 739

DN300: 874

DN350: 1011

DN400: 1168‌1