What are the different types of welded pipes?

What are the different types of welded pipes?

Welded steel pipe refers to a steel pipe with seams on the surface that is welded after bending and deforming a steel strip or steel plate into a circular, square, etc. shape. The blank used for the welded steel pipe is steel plate or strip steel.

Classification of welding methods

1. According to different welding methods:

Arc welded pipes, high frequency or low frequency resistance welded pipes, gas welded pipes, furnace welded pipes, Bondi pipes, etc.

Electric welded steel pipe: used in oil drilling and machinery manufacturing, etc.

Furnace welded pipe: It can be used as water gas pipe, etc., large-diameter straight seam welded pipe is used for high-pressure oil and gas transportation, etc.; spiral welded pipe is used for oil and gas transportation, pipe piles, bridge piers, etc.

2. Classified by weld shape:

It can be divided into straight seam welded pipe and spiral welded pipe.

3. Classified by purpose:

According to the purpose, it is divided into general welded pipe, galvanized welded pipe, oxygen blown welded pipe, wire casing, metric welded pipe, idler pipe, deep well pump pipe, automobile pipe, transformer pipe, electric welded thin-walled pipe, electric welded special-shaped pipe and spiral welded pipe.

4. Classification by end shape:

It is divided into circular welded pipes and special-shaped (square, flat, etc.) welded pipes.

Straight seam high-frequency welded pipe: simple production process, high production efficiency, low cost, and rapid development.

Spiral steel pipe: The strength is generally higher than that of the straight seam welded pipe. It can produce welded pipes with larger diameters with narrower blanks, and welded pipes with different diameters can also be produced with the same width of blanks. But compared with the straight seam pipe of the same length, the weld length is increased by 30~100%, and the production speed is lower. Therefore, most of the welded pipes with smaller diameters adopt straight seam welding, and most of the large diameter welded pipes adopt spiral welding.

Galvanized steel pipe: In order to improve the corrosion resistance of steel pipes, general steel pipes (black pipes) are galvanized. Galvanized steel pipe is divided into two types: hot-dip galvanized and pre-galvanized, and the hot-dip galvanized galvanized layer is thicker.

Production process of spiral steel pipe and straight seam high frequency welded pipe

Straight seam high-frequency welded pipe: Straight seam high-frequency welded pipe (ERW) is to heat and melt the edge of the tube billet by using the skin effect and proximity effect of high-frequency current after the hot-rolled coil is formed by the forming machine, Under the action of pressure welding to achieve production.

Spiral steel pipe: The raw material of spiral steel pipe is strip steel coil, welding wire and flux. Before forming, the strip steel is leveled, trimmed, planed, surface cleaned, transported and pre-bent. The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, misalignment and weld gap are strictly controlled. After cutting into single steel pipes, the first three steel pipes in each batch must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion status of the welds, surface quality of the steel pipes, and non-destructive testing to ensure that the pipe making process is qualified. to be officially put into production.

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