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What is the difference between straight welded pipe and general welded pipe?

Posted by:Rain Time:2019.07.03 03:33

Generally welded pipes are used to deliver low pressure fluids. Made of Q195A, Q215A, Q235A steel. It can also be made of other 

mild steel that is easy to weld. The steel pipe is subjected to experiments such as water pressure, bending and flattening, and has 

certain requirements on the surface quality. Usually, the delivery length is 4-10 m, and the fixed length (or double rule) is often 

required for delivery.

The straight seam welded pipe is formed by bending a steel plate or a steel strip and then welding. Commonly used materials are 

generally Q235A, Q235B, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, 16Mn, 20#, Q345, L245, L290, X42, X46, X70, X80 

and so on.

Straight seam welded pipes are divided into straight welded pipes and spiral welded pipes according to the form of welds. According 

to the application, it is divided into general welded pipe, galvanized welded pipe, blown oxygen welded pipe, wire casing, metric 

welded pipe, idler pipe, deep well pump pipe, automobile pipe, transformer pipe, electric welding thin wall pipe, electric welding 

special pipe and spiral welded pipe.

Straight seam steel pipes are mainly used in domestic water supply engineering, petrochemical industry, chemical industry, electric 

power industry, agricultural irrigation, and urban construction. For liquid transportation: water supply and drainage. For gas 

transportation: gas, steam, liquefied petroleum gas. For structural use: for piling pipes, for bridges, for piers, roads, building structures, 


Welded steel pipe, also called welded pipe, is cut into narrow steel bars by steel strips and then cold-wrapped into a tubular shape by a 

die. The special welder then welds a pipe joint. The outer weld is polished and bright. The inner burr of the general welded pipe is not 

hit. Only the precision welded pipe is used to make internal burrs.

According to the standard of GB3092 "welded steel pipe for low-pressure fluid transportation", the nominal diameter of the welded pipe 

is 6~150mm, the nominal wall thickness is 2.0~6.0mm, and the length of the welded pipe is usually 4~10m, which can be fixed length 

or multiple length. 

Welded steel pipes shall be subjected to mechanical performance tests, flattening tests and flare tests, and shall meet the requirements 

specified in the standard. The steel pipe should be able to withstand a certain internal pressure, and if necessary, carry out a pressure 

test of 2.5 Mpa to maintain no leakage for one minute.

The low-pressure fluid welded pipe is a kind of straight seam welded pipe. Generally, the water and gas are transported. After the welding 

is completed, the water pressure test is performed more than the ordinary welded pipe. Therefore, the low-pressure fluid pipe is generally 

higher than the ordinary straight-welded pipe. Commonly used materials for welded pipes are: Q235A, Q235B, 16Mn, 20#, Q345, L245, 

L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.

Straight seam welded pipe has simple production process, high production efficiency, low cost and rapid development. The strength of the 

spiral welded pipe is generally higher than that of the straight welded pipe. It is possible to produce a welded pipe with a larger diameter 

by using a narrow blank, and it is also possible to produce a welded pipe having a different pipe diameter with a blank of the same width.

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