Introduction of seamless steel pipe and its main varieties

Seamless steel pipes are widely used in our daily life and are one of the important materials in engineering and manufacturing. Commonly used specifications for seamless steel pipes are DN20 and DN70, and the wall thickness is 3.2 mm, 4mm, 6mm, 8mm, 10mm, 12mm, 16mm and 20mm. Here are some of the main varieties of seamless steel pipes:

1. Seamless carbon steel pipe: it is made of hot-rolled or cold-rolled steel plate or steel strip structural parts. The limit of chemical composition is based on ASTM A106. ASTM A106 includes three series of A, B and C. The use temperature is below 450℃. The used steel pipes are seamless steel pipes with high quality carbon structural steels.

2. Seamless stainless steel pipe: it is made of 20#, 304 or 316 stainless steel plate or steel strip structural parts. Stainless steel seamless steel pipes are widely used in petroleum, chemical and other industries. In mechanical industry, stainless steel seamless steel pipe is used in manufacturing parts and components.

3. Seamless alloy steel pipe: alloy steel is a kind of steel with a alloy element content of more than 5%. Alloy steel not only has the characteristics of general carbon steel, but also has higher mechanical strength. According to different application requirements and the needs of production cost control, it can be divided into low and medium alloy steel and high alloy steel, including different steel grades.

4. Seamless rounded pipe: for manufacture a variety of mechanical parts that require bending and torsional strength, as a flame-cutting parts, special-shaped and multi-segment complex parts. Round seamless steel pipe is generally manufactured by hot rolling process and then cold rolled or hot piercing through the expansion of mandrel.

5. Seamless thick-walled steel pipe: it refers to seamless steel pipe of various specifications with a wall thickness of more than 20mm. Its manufacture method includes hot rolling and cold rolling. Hot rolling is carried out at high temperature, and cold rolling is carried out low temperature.

6. Seamless hot-rolled steel pipe: it is rolled by hot working and hot rolling. Hot rolling is divided into general steel pipe, low and medium pressure boiler steel pipe, high pressure boiler steel pipe, alloy steel pipe, stainless steel pipe, petroleum cracking pipe and other steel pipes, and various kinds of steel pipes are produced.

7. Seamless cold rolled steel pipe: it is generally made of 10, 20 and other low carbon steel billets. The production process is cold rolling or cold drawing. The product is of high precision, good surface quality, excellent chemical composition and good mechanical properties.

8. Seamless precision steel pipe: it is a kind of hollow cross section, which is circular, square or rectangular and made of thin walled metal pipe. Its wall thickness is uniform and its section is bright and clean. Its production process is cold rolling or cold drawing. The performance of precision steel pipe is better than that of general pipe, and the price is higher.

9. Seamless thin-walled steel pipe: it is a kind of seamless steel pipe with thin wall thickness. It is mainly used for conveying fluids such as oil, natural gas, water, gas, steam and so on. Its outer diameter is 6mm and the wall thickness is 0.2-2.5mm. According to different mechanical property requirements of various products, the material of thin walled steel pipe is also thicker.

10. Seamless insulated steel pipe: it is a kind of insulated steel pipe, which is made of seamless steel tube as the basic material for surface weathering treatment. Its production process is middle hot rolling and hot piercing. When manufacturing, it is necessary to add thermal insulation layer, which is widely used in oil drilling production, chemical and other industries.

The above is the introduction of the main varieties of seamless steel pipes. As an important material in engineering and manufacturing, it is of great significance for people to select the products according to their needs. Its important to choose the steel pipe with the right materials and specifications for different operations.

Seamless steel pipe is a kind of long steel with a hollow section and no joint around it. It is mainly used for conveying fluids such as petroleum, natural gas, coal gas, water, and some solid materials such as pipelines andetc.

The main types of seamless steel pipes are: cold drawn seamless steel pipe (10#-45#, 16Mn, Q345), hot rolled seamless steel pipe (A53, A106B, 20#, Q235), thermal expansion steel pipe, and so on.

1. Cold drawn seamless steel pipe: It is made by punching a hole of the steel pipe, and then hot rolling, cold rolling or cold drawing at room temperature to make it into a steel pipe with a small size and high precision. Its process flow is: round hot-rolled steel - peeling - grinding - cold drawing - straightening - cutting - finished product inspection. Its advantages are small size and good surface finish;

2. Hot rolled seamless steel pipes: Its process flow is: round hot-rolled steel - perforation - three-roll cross-rolling - sizing and the steel pipe is rolled and formed by machine. Its advantages are good plasticity and toughness, easy production and machining, relatively low cost, and small size range.

3. Thermal expansion steel pipe: It is a thermal expansion process that is heated to expand the steel pipes. Its advantages are easy to operate and quick to produce, and the cost is relatively low;

4. Other seamless steel pipes: such as cold drawn precision steel pipe, hot rolled seamless steel pipe, alloy steel and stainless steel pipe, short for non-standard steel pipes, all belong to the category of seamless steel pipes, which can be customized according to the needs.

Seamless steel pipes are widely used in machinery manufacturing, petrochemical industry, gas transportation and other fields, and are popular in the market. With the continuous progress of technology and the development of society, seamless steel pipe production and practical application will become more and more extensive.