Carbon steel pipe material and classification

What is Carbon Steel Pipe？

Carbon steel pipe (CS pipe) is a durable material made of carbon steel, a steel alloy of iron and carbon in which the carbon content is less than 2 percent steel. Carbon steel can be further divided into low carbon steel, medium carbon steel and high carbon steel, mainly depending on the carbon content in the steel. Due to its strength and ability to withstand pressure, carbon steel pipes are used in a variety of heavy industries such as infrastructure, ships, stills, and fertilizer equipment.

Advantages of carbon steel pipes:

1. Carbon steel piping provides safety and durability. It is an ideal material for structural applications due to its impact resistance and its imperceptibility to harsh environmental conditions such as stress or extreme weather.

 

2. The incredible strength of carbon steel means that carbon steel pipes can be made thinner and use less material while still being able to transport large volumes. This makes carbon steel piping a cost-effective material. Not only can the use be reduced, but the carbon steel can also be recycled, which is environmentally friendly and economical.

 

3. Carbon steel pipe is a versatile material due to its ease of fabrication. We can produce products in various thicknesses and sizes. It's also easy to cut and bend to fit wherever needed. It also connects easily to fittings, valves and other plumbing fittings.

Types of carbon steel:

Low carbon steel (also known as mild steel): 

The carbon content is usually between 0.04% and 0.30%. Low carbon steel has good ductility and toughness, can be processed hot and cold, and is easy to weld. Commonly used low carbon steels include ASTM A36, A572, A1008, SAE1006, Q235, etc.

Medium carbon steel: 

The carbon content is usually between 0.30% and 0.60%. Medium carbon steel has high strength and hardness, but low ductility and toughness. Commonly used medium carbon steels include 45# steel, 40Cr and so on.

High carbon Steel: 

The carbon content is usually between 0.60% and 2.00%. High carbon steel has high strength and hardness, but low ductility and toughness, and poor weldability. Commonly used high carbon steels include 65Mn, T8, T10, etc.

Classification of carbon steel pipe:

Carbon steel pipes can be divided into seamless pipes and welded steel pipes according to the production method:

1) Seamless steel pipes are made by hot rolling or cold rolling (drawing), and have high strength and tightness. 

a. Hot-rolled carbon steel pipe‌: The outer diameter of this type of steel pipe is generally greater than 32mm, and the wall thickness is between 2.5-75mm. Hot-rolled seamless pipes are mainly used for general steel pipes, low and medium pressure boiler tubes, high pressure boiler tubes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes and other special purpose steel pipes.

b. Cold-rolled (drawn) carbon steel pipe‌: Compared with hot-rolled carbon steel pipes, cold-rolled carbon steel pipes have higher dimensional accuracy, their outer diameter can reach 6mm, and their wall thickness can reach 0.25mm. The types of cold-rolled seamless pipes include carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless thin-walled steel pipes and special-shaped steel pipes, etc., 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 also include carbon thin-walled steel pipes, alloy steel thin-walled steel pipes, and stainless steel Thin-walled steel pipes, special-shaped steel pipes. Which are commonly used as engineering precision mechanical tubes hydraulic equipment and mechanical parts, such as shafts, bearings, sleeves, transmission parts, etc.

2) Welded steel pipe is made by rolling steel plate or steel strip into a cylindrical shape, and then connecting the weld seams by resistance welding, submerged arc welding and other methods.

In addition, carbon steel pipes can be further subdivided according to the shape of the weld: seamless steel pipes (SMLS), longitudinal seam steel pipes (LSAW), spiral steel pipes (SSAW) and high-frequency welded steel pipes (ERW pipe). Seamless steel pipes are made by perforating steel ingots or solid tube blanks into gross pipes, and then hot rolling, cold rolling or cold drawing; straight seam steel pipes and spiral steel pipes are formed through different manufacturing processes; high frequency welded steel pipes It is a steel pipe welded by high-frequency current. These classifications are based on different manufacturing processes and application requirements to meet various industrial and civil needs. ‌

Application fields of carbon steel pipe:

Carbon steel pipe has good corrosion resistance, pressure bearing capacity and machinability, and is widely used in many fields.

1. Oil and natural gas industry: Carbon steel pipe is an important pipeline material for transporting oil and natural gas, with high strength, reliability and corrosion resistance.
2. Construction and structural engineering: Carbon steel pipes are used in construction and structural engineering, such as bridges, high-rise buildings, roads and tunnels, etc., to support and transmit loads.
3. Automobile manufacturing industry: Carbon steel pipes are used in exhaust pipes, frame and chassis and other components in the automobile manufacturing industry, and have good wear resistance and strength.
4. Mechanical engineering: Carbon steel pipes are used in conveying systems, pressure vessels, hydraulic systems and other components in mechanical engineering, and have pressure bearing capacity and reliability.

5. Chemical industry: Carbon steel pipes are used in the chemical industry for conveying systems, reactors, storage tanks and other components, with corrosion resistance and high temperature resistance.

Go here to learn more about" Carbon Steel Pipe Sizes" or  "Schedule 80 Carbon Steel Pipe"

Carbon Steel Material Introduction:

Carbon steel, as a type of steel material, mainly consists of iron and carbon. The carbon content will affect the hardness, strength and plasticity of the steel. This steel is one of the most commonly used materials in industry and construction and is widely used due to its relatively low cost and easy workability. According to the different carbon content, carbon steel can be divided into three categories: low carbon steel (mild steel pipe), medium carbon steel and high carbon steel.

1) Chemical composition and properties of carbon steel

The performance of carbon steel mainly depends on its chemical composition. The main elements include:
• Carbon (C): Increases hardness and strength, decreases plasticity.
• Manganese (Mn): Enhances hardness, improves weldability and impact toughness.
• Silicon (Si): Increases strength, but excessive amounts reduce plasticity and toughness.
• Sulfur (S) and Phosphorus (P): Usually present as impurities, excess can reduce the properties of steel.

2) Physical properties of carbon steel

The physical properties of carbon steel are mainly reflected in:
• Mechanical properties: including tensile strength, yield strength, hardness and toughness, etc.
• Heat treatability: Heat treatments such as annealing, normalizing, quenching and tempering can be carried out to change the internal structure of the steel to obtain different properties.
• Weldability: Low carbon steel has good weldability, while high carbon steel is prone to cracks during welding due to its high hardness.

3) Carbon steel processing technology

There are various processing techniques for carbon steel, the main techniques are:
• Cold working: such as cold rolling, cold drawing, etc., can improve the strength and hardness of steel.
• Hot processing: such as hot rolling, forging, etc., usually performed after heating to a certain temperature to obtain the required shape and size.
• Surface treatment: Such as galvanizing, painting or spraying anti-corrosion layer, etc., which can improve the corrosion resistance of carbon steel.

4) Corrosion resistance of carbon steel

Carbon steel is less resistant to corrosion than other types of steel, such as stainless steel. However, through surface treatment such as galvanizing or coating with special coatings, its ability to resist environmental factors can be improved to a certain extent.

5) Application fields of carbon steel

Due to its excellent performance and economy, carbon steel is widely used in:

• Construction industry: used in building structures, support frames, steel beams, etc.
• Manufacturing: Materials as machine parts, automotive components, tools and cutters.
• Infrastructure: plays an important role in the construction of bridges, railways, and highways.
• Pipeline transportation: Mild steel pipes are widely used to transport water, gas, etc.

6) Sustainability and recycling of carbon steel

Carbon steel meets the requirements of sustainable development due to its high recyclability and renewability. Waste carbon steel materials can be recycled through smelting and reprocessing, reducing resource consumption and environmental impact.

As a basic industrial material, carbon steel plays an important role in various fields. Through continuous research and improvement of its performance, its irreplaceability in modern industry is ensured. With the advancement of technology and the strengthening of awareness of environmental protection, the production and application of carbon steel will pay more attention to efficiency and sustainability.

Read more: Carbon steel vs Stainless steel or Seamless vs. Welded Tubing