Types of seamless carbon steel pipes

Carbon steel pipe is a type of seamless pipe used in construction and manufacturing to convey fluids and solids. Although there are many types of carbon steel pipe available, they all share some key characteristics, including strength, hardness, and durability. Types of seamless carbon steel pipe vary by application, each for a specific purpose. This article will explore the different types of seamless carbon steel pipe, their pros and cons, and best practices for using them.

The various types of seamless carbon steel pipes available today can be divided into three main categories: Hot rolled seamless steel pipe (hrs), cold rolled seamless steel pipe (crs) and cold drawn seamless steel pipe (cds). Within each category there are several variants dedicated to specific applications (such as oil or gas transportation) or certain intensities.

Hot rolled seamless tube

The hot-rolled seamless tube is made from a heated round billet and formed into a cylindrical shape. They are often used in engineering applications requiring higher strength than cold rolled or cds tubes. The heat treatment process makes them extra hard and strong, able to withstand high temperatures and pressures.

1. Process

2. Advantages

Advantages of hot-rolled seamless tubes includes cost-effectiveness, strong construction, and the ability to customize shapes.

3. Disadvantages

Drawbacks include their weight, which can make them difficult to transport and install.

4. Application

Hot rolled seamless pipe is often used for larger projects involving higher pressures and temperatures.

Oil casing (API 5CT J55/N80)

Building structure support (such as plant columns)

Ordinary fluid delivery pipeline (low-pressure water, gas)

Boiler pipe for high temperature and high pressure.

Cold rolled seamless tube

Cold-rolled seamless pipe is made by shaping hot-rolled steel through a series of rolls. Unlike hot rolled steel, cold rolled steel is harder and more brittle. It also allows for more precise machining and shaping, making it ideal for equipment that requires precision.

1. Process

2. Advantages

The advantages of cold-rolled tubes include greater resistance to corrosion and wear, better machinability, and lower cost.

3. Disadvantages

Disadvantages of cold-rolled pipe include insufficient strength compared to hot-rolled steel, a greater likelihood of cracking, and limited customizability.

4. Application

Cold-rolled tubing is often used in smaller applications that don't require as much strength or precision.

Cold drawn seamless tube

Cold-drawn seamless tubes are made by forcing hot-rolled tubes through one or more dies. This forces the material to become denser, making it stronger. They are ideal for applications where strength and pressure resistance are critical, such as automotive hydraulic lines and tubing.

1. Advantages

Advantages of cold-drawn seamless tubing include high strength, low cost, and the ability to manufacture precise shapes.

2. Disadvantages

Drawbacks include their potential to crack if not properly tempered, lack of flexibility, and limited customizability.

3. Application

Cold drawn seamless tubing is most commonly used in automotive and industrial applications.

Differences between cold rolling and cold drawing

1. Cold rolling is a radial compression forming process, while cold drawing is an axial stretch forming process.

2. Multiple cold rolling passes provide better control over dimensional accuracy, while uniaxial stretch cold drawing can easily lead to micro-ovality.

3. Cold-rolled tubes achieve uniform work hardening and a fatigue life 30% to 50% higher than cold-drawn tubes.

4. For critical pressure-bearing components (such as hydraulic systems), cold-rolled tubes should be preferred, even if the cost increases by 30%, as this significantly reduces the risk of tube bursts.

Selection recommendations

1. Choose hot-rolled tubes

For low cost and large diameter requirements (e.g., water pipes over DN400).

2. Choose cold-drawn/cold-rolled tubes

For high-precision, high-strength applications (e.g., hydraulic systems).

In conclusion

Seamless carbon steel pipes are widely used in construction and manufacturing. Each type of plumbing serves specific needs and applications, so it's important to understand their pros and cons before using them in a project. Hot-rolled seamless tubes are the most cost-effective and widely used, while cold-rolled and cold-drawn tubes are more precise and provide greater strength and resistance. Regardless of the type of seamless carbon steel pipe chosen, proper installation, handling, and maintenance will ensure the longevity of any project.