What is welded pipe

Welded pipe is also called welded steel pipe. It is cut into narrow-band steel by steel strip, and then curled into tube by die cold processing. The high frequency submerged arc welding machine then welds a pipe seam. Due to different welding processes, it is divided into resistance welded pipe and automatic arc welded pipe. Due to different welding forms, it is divided into straight seam welded pipe and spiral welded pipe;

Straight seam welded pipe

Straight seam welded pipe: the steel pipe made of hot-rolled or cold-rolled steel plate or steel strip is welded in straight seam on the welding equipment. The pipes obtained are called straight seam welded pipe.

It is named because the welded joint of the steel pipe is in a straight line. According to different purposes, it can be roughly divided into scaffold pipe, fluid pipe, wire sleeve and support pipe

Common materials: q195a, Q235B, q355b, steel strip manufacturing.

Weight formula: (outer diameter wall thickness) wall thickness 0.02466 = kg / M (weight per meter). Common specifications: outer diameter 20mm-2500mm, thickness 1MM-30MM, length 6m, 12m. It can also be measured according to the length required by customers

Specification table of longitudinal welded pipe

Nominal size national standard thickness mm

Spiral steel pipe

Spiral steel pipe is a spiral seam steel pipe made of strip steel coil as raw material, often formed by warm extrusion and welded by automatic double wire double-sided submerged arc welding process. The spiral steel pipe sends the strip steel to the welded pipe unit. After rolling by multiple rollers, the strip steel is gradually rolled up to form a circular tube blank with opening gap. Adjust the reduction amount of the extrusion roller to control the weld gap at 1-3mm and make both ends of the welded junction flush.

Ordinary material: Q235A, Q235B, 10 #, 20 #, Q345 (16Mn)

Pipeline pipe: L245 (b), L290 (X42), l320 (X46), L360 (X52), L390 (X56), L415 (X60), L450 (X65), l485 (X70), l555 (X80)

Weight formula: [outer diameter - wall thickness) wall thickness 0.02466 = kg / M (weight per meter) common specifications: outer diameter 159mm-1500mm, thickness 1mm-20mm, length: 6m, 12m. It can also be measured according to the length required by customers

Welded rectangular tube

Welded rectangular tube is a kind of light thin-walled steel tube with hollow square section, also known as steel cold-formed profile. It is a section steel with square section shape and size, which is made of Q235B and Q345B hot-rolled or cold-rolled strip or coil as the base material, cold bending and forming, and then high-frequency welding. Commonly used in construction, machinery manufacturing, steel construction projects, shipbuilding, solar power generation support, steel structure engineering, etc;

Square tube: 200 ×  200x8mmx12m refers to square steel pipe with height of 200mm, width of 200mm, thickness of 8mm and length of 12m.

Square tube: 200 ×  100x5mmx6m refers to rectangular steel pipe with height of 200mm, width of 100mm, thickness of 5mm and length of 6m. Common specifications: the side width of square pipe is 15mm * 15mm-600mm * 600mm, and the thickness is 1.0mm-20mm. Rectangular pipe edge width 30mm * 20mm-400mm "300mm, thickness 1.0mm-20mm

Welded pipe welded steel pipe is made of steel plate or strip welded after crimping. It has the advantages of simple production process, high production efficiency, many varieties and specifications and less equipment investment. It has replaced seamless steel pipe in more and more fields. Welded steel pipes are divided into straight seam welded pipe (welded pipe with smaller diameter) and spiral welded pipe (welded pipe with smaller diameter) according to the form of weld. According to the specification and size table in the current national standard, it is sorted from small to large according to the outer diameter * wall thickness. Common materials of welded pipes are: Q235A, Q235C, Q235B, 16Mn, 20#, Q345, L245, L290, X42, X46, X60, X80, 0Cr13, 1Cr17, 00cr19ni11, 1Cr18Ni9, 0cr18ni11nb, etc.

Welded pipe USES

The strength of spiral welded pipe is generally higher than that of straight welded pipe. It can produce welded pipe with larger pipe diameter with narrow blank, and welded pipe with different pipe diameter with blank of the same width. However, compared with the straight seam pipe with the same length, the weld length increases by 30 ~ 100%, and the production speed is low.

Welded pipes with large or thick diameter are generally made of steel blank directly, while small welded pipes and thin-walled welded pipes only need to be welded directly through steel strip. Then after simple polishing, wire drawing is OK.

The products are widely used in tap water engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation and urban construction. It is one of the 20 key products developed in China.

For liquid transportation: water supply and drainage. For gas transmission: gas, steam and liquefied petroleum gas.

For structure: as pile driving pipe and bridge; Pipes for wharf, road, building structure, etc.