How is longitudinal electric welded steel pipe produced?

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Where is the longitudinal electric welded steel pipe used today? This is a product that in modern conditions is widely used in various industries.

Application

As a rule, it is placed where it is necessary to transport gaseous or liquid substances with a high degree of aggressiveness. Therefore, pipes of such a plan can be found in mechanical engineering, when laying heating networks at the main level.

Steel electric-welded longitudinal pipe is used in industry. It is impossible to do without it in oil production, the construction of scaffolding, in the manufacture of furniture or even sports equipment. Its versatility, good performance, excellent welding capabilities (including home welding) allow it to be used in domestic conditions for the formation and repair of engineering networks.

Sizes

Steel electric-welded longitudinal pipes, GOST for which has the number 10704–91, are produced in a certain random length for a specific diameter. For example, with the value of the latter up to 0.3 cmthe product should not be less than 2 meters long, and if this parameter exceeds 15.2 cm, then the length cannot be less than 5 m. There are also dimensional options when the pipe length is within certain limits for a given diameter. So, for an indicator up to 7 cm, the size of the article can vary from 5 to 9 meters.

Production

What properties should such a pipe have? Steel electric-welded longitudinal modification during production must have parameters that meet state requirements for articles used in a particular field. For example, pipes for oil and gas pipelines (trunk) are made in accordance with GOST 20295-85. They are formed by welding of an electric arc or contact type (the latter using high frequency currents) with different strength classes (from K34 to K60).

For the manufacture of products, heat-treated or hot-rolled steel (quiet or semi-quiet) with a C (carbon) content of not more than 0.2% by weight is used. Its sheets are twisted into a pipe, after which the edges of the sheets are heated by current and squeezed by rolls (electrode rings). The speed of such processes on special machines can be quite high (tens of meters of welding per minute, depending on the wall thickness). The operation is almost always accompanied by cutting products of the desired length using cutting equipment.

Steel welded longitudinally welded pipe can be heat treated both along the entire length and only along the weld. On thethe base metal of the product is not allowed to have captivity, flaws, cracks, sunsets and delaminations. Surface defects of an acceptable level should not be corrected by welding (only grinding) in order to maintain the required degree of product reliability. Pipe welds should not have lack of penetration, cracks, pores, fistulas, slag inclusions that come to the surface.

Cost

How expensive are longitudinally welded steel pipes? The price for them, depending on the manufacturer, steel grade, diameter and wall thickness, can range from 32 to 45-48 thousand. When buying, you should always pay attention to compliance with GOST, because within its framework, the products pass the necessary tests, including the share of the viscous component, impact bending at different temperatures, tensile, ovality of the article, the length of its deviation, the quality of the metal in welded joint, etc.

Information about which product is planned to be purchased can be found from the stamp on the pipe. It must be mandatory affixed at a distance of 10-150 cm from one of the ends, marked with paint and include the year of manufacture, technical control data, steel grade, individual pipe (batch) number, trademark of the manufacturer.