Classification by welding process: welded steel pipe

Classification by welding process: welded steel pipe

Welded steel pipe refers to the steel pipe with joints on the surface after bending the steel strip or steel plate into a round or square shape. The blank used for welding steel pipe is steel plate or strip steel.

Classification of welding methods

According to different welding methods, it can be divided into arc welding pipe, high frequency or low frequency resistance welding pipe, gas welding pipe, furnace welding pipe, Bondi pipe, etc.

Electric welded steel pipe: Used in oil drilling and machinery manufacturing.

Furnace welded pipe: can be used as water and gas pipe, big mouth straight seam welded pipe for high pressure oil and gas transmission, etc.; Spiral welded pipe is used for oil and gas transmission, pipe pile, bridge pier, etc.

Classification by weld shape

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

Straight seam welded pipe

Simple production process, high production efficiency, low cost, rapid development.

Spiral welded pipe

The strength is generally higher than that of straight welded pipe, and welded pipe with larger diameter can be produced with narrower billet, and welded pipe with different diameter can also be produced with billet of the same width. But compared with the same length of straight seam pipe, the weld length is increased by 30~100%, and the production speed is lower. Therefore, small diameter welded pipe mostly adopts straight seam welding, large diameter welded pipe mostly adopts spiral welding.

Spiral welded steel pipes are divided into automatic submerged arc welded steel pipes and high frequency welded steel pipes.

A. Spiral welded automatic submerged arc welded steel pipes are divided into a and B types according to the pressure of the conveying medium. Class A pipes are generally made of ordinary carbon steel Q235, Q235F and ordinary low-alloy structural steel 16Mn, and Class B pipes are made of Q235, Q235F, Q195 and other steels, which are used as low-pressure fluid conveying pipes

b, spiral joint high frequency welded steel pipe spiral joint high frequency welded steel pipe, there is no unified product standard, generally using ordinary carbon steel Q235, Q235F and other steel manufacturing.

Classification by use

According to its use, it is divided into general welded pipe, galvanized welded pipe, oxygen blown welded pipe, wire casing, metric welded pipe, roller pipe, deep well pump pipe, automobile pipe, transformer pipe, electric welded thin-wall pipe, electric welded special-shaped pipe and spiral welded pipe.

Ordinary welded pipe

Common welding pipe to transfer low pressure fluid. Made of Q195A, Q215A, Q235A steel. It can also be made of other mild steels which are easy to weld. Water pressure, bending, flattening and other experiments should be carried out on the steel pipe, which has certain requirements on the surface quality. Usually, the delivery length is 4-10m, and the delivery length is usually fixed (or multiple) feet. The specification of the welded pipe is expressed by the nominal diameter (mm or inch). The nominal diameter is different from the actual diameter. The welded pipe has two kinds of ordinary steel pipe and thickened steel pipe according to the specified wall thickness, and the steel pipe has two kinds of thread and no thread according to the form of the pipe end.

Galvanized steel pipe

In order to improve the corrosion resistance of the steel pipe, the general steel pipe (black pipe) is galvanized. Galvanized steel pipe is divided into two kinds: hot dip galvanized and electric galvanized. The layer of hot dip galvanized is thick and the cost of electric galvanized is low.

Oxygen blow welding pipe

Used for steel blowing oxygen pipe, generally with small caliber welded steel pipe, specifications by 3/8 "-2" eight. Made of 08, 10, 15, 20 or Q195-Q235 steel strip. In order to prevent corrosion, some are aluminized.

Wire bushing

It is an ordinary carbon steel electrowelded steel pipe, used in concrete and various structural power distribution engineering, commonly used nominal diameter from 13-76mm. Wire sleeve tube wall is thin, most of the coating or galvanized after use, require cold bending test

Metric welded pipe

Specifications with seamless pipe form, with outer diameter * wall thickness mm welded steel pipe, with ordinary carbon steel, high quality carbon steel or general low alloy steel tropical, cold zone welding, or made of tropical welding and then cold drawing method. Metric welded pipe can be divided into thin-walled, commonly used as structural parts, such as transmission shaft, or fluid transport, thin-walled used to produce furniture, lamps, etc., to ensure the strength and bending test of steel pipe.

Idler tube

Used for electric welding steel pipe for belt conveyor idlers, generally made of Q215, Q235A, B and 20 steel, diameter 63.5-219.0mm. There are certain requirements for tube bending, end face perpendicular to the center line and ovality, and water pressure and flattening tests are generally carried out.

Transformer tube

Used for the manufacture of transformer heat pipe and other heat exchangers, made of ordinary carbon steel, requiring flattening, flaring, bending, hydraulic tests. The steel pipe is delivered with fixed or double length, which has certain requirements on the bending degree of the steel pipe.

Irregular tube

Square pipe, rectangular pipe, cap pipe, empty rubber steel door and window steel pipe welded from ordinary carbon junction structural steel and 16Mn steel strip, mainly used for agricultural machinery components, steel window doors, etc.

Electrowelded thin-walled tube

Mainly used to make furniture, toys, lamps and so on. At present, the thin wall tube made of stainless steel belt is widely used in senior furniture, decoration, fence and so on.

Spiral welded pipe

Is the low carbon carbon structural steel or low alloy structural steel strip according to a certain Angle of helix (called forming Angle) into a tube blank, and then welded pipe joints made, it can use narrow strip steel to produce large diameter steel pipe. Spiral welded pipe is mainly used for oil and natural gas pipeline, its specification is expressed by outer diameter * wall thickness. Spiral welded pipe has one side welding and two side welding, welding pipe should ensure that the hydraulic test, tensile strength of the weld and cold bending performance should meet the requirements.

Classified by end shape

It is also divided into round welded pipe and special shape (square, flat, etc.) welded pipe.