Detailed Explanation of Seamless Pipe Grade

The seamless pipe is widely used in petrochemical, fertilizer, machinery, aviation and other fields due to their excellent pressure resistance and high temperature resistance, such as seamless precision tube, seamless hydraulic tube, etc. The grade classification of seamless pipes is determined according to the production process and related chemical composition when manufacturing seamless pipes. According to the provisions of the national standard GB/T14975-2002, the grades of seamless pipes can be divided into five grades, namely A, B, C, D, and E, with the grades increasing in sequence.

Classification of seamless pipe grades

1. Grade A seamless pipe

Grade A seamless pipes have relatively high chemical composition requirements, and their heat treatment quality and mechanical properties are also required to be high. They are mainly suitable for the manufacture of high-pressure pipeline, boiler tube and high-pressure gas cylinder. Common Grade A seamless pipe materials are: 10#, 20#, 12CrMo, etc.

2. Grade B seamless pipes

Grade B seamless pipes have lower chemical composition and mechanical property requirements, and the production process is relatively simple. They are mainly suitable for general pressure occasions, such as medium and low pressure pipelines and structural pipes. Common B-grade seamless pipe materials include: 10#, 20#, Q345B, etc.

3. C-grade seamless pipe

The chemical composition and mechanical property requirements of C-grade seamless pipe are slightly higher than those of B-grade, but slightly lower than those of A-grade. It is mainly suitable for general pressure occasions, such as machinery manufacturing and general engineering pipelines. Common C-grade seamless pipe materials include: 10#, 20#, 35#, etc. In some occasions where there are certain performance requirements but do not need to meet the A-level standard, such as the manufacture of certain specific heat exchanger components or general pup joints, Grade C seamless pipes are a more appropriate choice.

4. D-grade seamless pipe

D-grade seamless pipe is mainly suitable for occasions where low-pressure fluids are transported. Its chemical composition and mechanical property requirements are relatively low. It is generally used for water supply and drainage pipelines and low-pressure transmission pipelines. Common D-grade seamless pipe materials include: 10#, 20#, etc.

5. E-grade seamless pipe

E-grade seamless pipe is mainly suitable for occasions such as transporting oil well slurry. Its chemical composition requirements are relatively high and its mechanical property requirements are relatively low. It is suitable for oil well slurry transportation and downhole pipelines. Common E-grade seamless pipe materials include: E75, X95, etc.

Related parameters of seamless pipes of different grades

The following table lists the main parameters of seamless pipes of different grades:

Note: "Variable" in the table means that the nominal pressure can be adjusted according to the actual working conditions and specific material properties.

Summary and purchase suggestions

The grade classification of seamless pipes is one of the important indicators when manufacturing seamless pipes. Seamless pipes of different grades are suitable for different pressure and temperature occasions, and their chemical composition and mechanical properties are also different.

1. Grade A: Suitable for high temperature and high pressure environments, such as high pressure gas cylinders, high pressure pipelines, etc.;

2. Grade B and Grade C: Mostly used in general pressure occasions, meeting the needs of medium and low pressure and conventional engineering;

3. Grade D: Suitable for low pressure fluid transportation, such as water supply and drainage systems;

4. Grade E: Adapt to special working conditions, especially those involving corrosive media (such as oil well slurry).

When purchasing seamless pipes, it is necessary to select the appropriate grade and material according to the actual use occasions, working conditions and safety standards to ensure the safety and economic benefits of equipment operation.

Read more: Seamless Steel Pipe Sizes