Carbon steel pipe is a common metal pipe made of elements such as carbon and iron. It has high strength, corrosion resistance, and high temperature resistance, and is used in construction, structures, and liquid transportation of water, oil, and gas. The specifications and sizes of carbon steel pipe refer to the parameters of the pipe such as the outer diameter, wall thickness, and length. Carbon steel pipe is manufactured using a variety of different technologies to produce pipes with various characteristics. The carbon content in carbon steel pipe can be as high as 2.1% of the total alloy weight. Any increase in the carbon percentage in the alloy used to manufacture carbon steel line pipe increases the hardness and tensile strength of the metal. Black carbon steel casing loses its ductility even if the carbon percentage increases.
What are the materials and compositions of carbon steel pipe?
Typical carbon steel pipe material grades include API 5L Grade B, X42 to X70, ASTM A106 B, ASTM A53 B, ASTM A252 Grade 3, and ASTM A333 Grade 6. Carbon steel pipes are mainly composed of carbon and iron, and may contain small amounts of other elements such as manganese, silicon, sulfur and phosphorus. The carbon content is usually between 0.04% and 2.1%. The increase in carbon content can increase the hardness and tensile strength of the steel pipe, but may reduce its ductility.
Main specifications of carbon steel pipes
Carbon steel pipes are available in a variety of specifications and sizes to suit different uses. Common specifications include:
Outer diameter: ranging from 6mm to 426mm
Wall thickness: ranging from 0.8mm to 15mm, the thickness of the pipe wall also has different specifications, and the common wall thickness ranges from 2mm to 50mm. The choice of wall thickness depends on the pressure bearing capacity of the pipe and the use environment.
Material: Common materials are 10#, 20#, 45#, Q195, Q235, Q345, etc.
Pipe diameter: usually expressed in outer diameter, and the common outer diameter ranges from 20mm to 1000mm.
Carbon steel pipes come in a very wide range of sizes, typically 1/2” NB to 36” NB.
The following carbon steel pipes are common standards and grades:
ASTM A/ASME SA 106: Includes grades A, B, and C, for seamless carbon steel pipes for high temperature service.
ASTM A/ASME SA 53: Includes grades A and B, covering
seamless steel pipe, welded (ERW), and galvanized hot-dip galvanized steel pipes.
API 5L: Includes PSL 1 grades A, B, X42, X46, X52, X56, X60, X65, and X70, mainly used for oil and gas pipelines.
ASTM A/ASME SA 333: Includes grades 1 and 6, for seamless and welded steel pipes for low temperature service.
ASTM A134 and ASTM A135: For electric resistance welded (ERW) steel pipes.
DIN 2440: For medium weight threaded connection pipes.
Carbon Steel Pipe Specifications
Carbon steel pipes are divided into two categories: hot rolled and cold rolled (drawn) steel pipes.
Hot-rolled carbon steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other steel pipes.
Cold-rolled (pulled) carbon steel pipes include general steel pipes, low and medium pressure boiler steel pipes, high pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes and other steel pipes, as well as carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless thin-walled steel pipes and special-shaped steel pipes. The outer diameter of hot-rolled seamless pipes is generally greater than 32mm, and the wall thickness is 2.5-75mm. The outer diameter of cold-rolled seamless steel pipes can reach 6mm, and the wall thickness can reach 0.25mm. The outer diameter of thin-walled pipes can reach 5mm, and the wall thickness is less than 0.25mm. The dimensional accuracy of cold rolling is higher than that of hot rolling.
Manufacturing process of carbon steel pipes
The raw material of carbon steel pipes is round tube billets. The round tube billets must be cut by a cutting machine into billets with a length of about 1 meter, and then sent to the furnace for heating via a conveyor belt. The billet is sent into the furnace for heating at a temperature of about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature control in the furnace is a key issue. After the round tube billet is taken out of the furnace, it must be pierced by a pressure piercing machine. Generally, the more common piercing machine is a tapered roller piercing machine. This piercing machine has high production efficiency, good product quality, large piercing and expansion, and can pierce a variety of steel types. After piercing, the round tube billet is successively subjected to three-roller oblique rolling, continuous rolling or extrusion. After extrusion, it must be removed from the tube and sized. The sizing machine uses a conical drill bit to rotate at high speed into the steel billet to punch holes to form a steel pipe. The inner diameter of the steel pipe is determined by the outer diameter length of the sizing machine drill bit. After sizing, the steel pipe enters the cooling tower and is cooled by water spray. After cooling, the steel pipe must be straightened. After straightening, the steel pipe is sent to the metal flaw detector (or water pressure test) by a conveyor belt for internal flaw detection. If there are cracks, bubbles, etc. inside the steel pipe, they will be detected. After quality inspection, the steel pipe must also pass strict manual selection. After the steel pipe is inspected, the number, specification, production batch number, etc. are sprayed with paint. Then it is hoisted into the warehouse by a crane.
Conclusion
Carbon steel pipes are widely used due to their excellent mechanical properties and wide range of applications. Understanding different specifications and standards helps to select suitable carbon steel pipes for specific industrial applications. With proper manufacturing processes, carbon steel pipes can meet various engineering needs, from construction to oil and gas pipeline systems.