Welded steel pipes refer to steel pipes with seams on the surface that are welded after bending and deforming steel strips or steel plates into round or square shapes. The production process of welded steel pipes is simple, the production efficiency is high, the steel pipes have many varieties and specifications, and the equipment is less, but the general strength is lower than seamless steel pipes. Since the 1930s, with the rapid development of high-quality strip continuous rolling production and the advancement of welding and inspection technology, the quality of welds has been continuously improved, and the variety and specifications of welded steel pipes have increased, and they have replaced non-products in more and more fields. Seam the steel pipe.
Welded steel pipe refers to a steel plate rolled into a tube, and then welded to form. The material is mostly Q235A or Q235B
The quality requirements are generally used for seamless pipes. The general requirements for quality requirements in place 4 are welded pipes. Welded pipes have the possibility of leakage and because they are welded after steel plate rolling, their compression resistance is much worse than seamless pipes. .
According to different welding methods, it can be divided into arc welded pipe, high frequency or low frequency resistance welded pipe, gas welded pipe, furnace welded pipe, Bondi pipe, etc. According to the weld shape, it can be divided into straight seam welded pipe and spiral welded pipe.
Electric welded steel pipes are used in oil drilling and machinery manufacturing. Furnace welded pipes can be used as water gas pipes, large-diameter longitudinally welded pipes are used for high-pressure oil and gas transportation, etc.; spiral welded pipes are used for oil and gas transportation, pipe piles, bridge piers, etc. Welded steel pipes have lower cost and higher production efficiency than seamless steel pipes. Longitudinal welded pipe has simple production process, high production efficiency, low cost and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. A narrower blank can be used to produce welded pipes with larger pipe diameters, and a billet with the same width can also be used to produce welded pipes with different pipe diameters. However, 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 smaller diameter welded pipes adopt straight seam welding, and the large diameter welded pipes mostly adopt spiral welding.
The billet used for welded steel pipe is steel plate or strip steel, which is divided into furnace welded pipe, electric welded (resistance welded) pipe and automatic arc welded pipe due to different welding processes. Because of its different welding forms, it is divided into two types: straight seam welded pipe and spiral welded pipe. Because of its end shape, it is divided into round welded pipe and special-shaped (square, flat, etc.) welded pipe. Welded pipes are divided into the following varieties due to their different materials and uses:
GB/T3091-1993 (galvanized welded steel pipe for low pressure fluid transportation). Mainly used to transport water, gas, air, oil, heating water or steam and other generally lower pressure fluids and other purposes. Its representative material is Q235A grade steel.
GB/T3092-1993 (galvanized welded steel pipe for low pressure fluid transportation). Mainly used to transport water, gas, air, oil, heating water or steam and other generally lower pressure fluids and other purposes. Its representative material is: Q235A grade steel.
GB/T14291-1992 (Welded steel pipe for mining fluid transportation). Mainly used for straight seam welded steel pipes for mine pressure, drainage and shaft gas discharge. Its representative material is Q235A, Grade B steel. GB/T14980-1994 (Large diameter electric welded steel pipe for low pressure fluid transportation). It is mainly used to transport low-pressure fluids such as water, sewage, gas, air, heating steam and other purposes. Its representative material is Q235A grade steel.
GB/T12770-1991 (stainless steel welded steel pipe for mechanical structure). Mainly used in machinery, automobiles, bicycles, furniture, hotel and restaurant decoration and other mechanical parts and structural parts. Its representative materials are 0Cr13, 1Cr17, 00Cr19Ni11, 1Cr18Ni9, 0Cr18Ni11Nb, etc.
GB/T12771-1991 (stainless steel welded steel pipe for fluid transportation). Mainly used to transport low-pressure corrosive media. Representative materials are 0Cr13, 0Cr19Ni9, 00Cr19Ni11, 00Cr17, 0Cr18Ni11Nb, 0017Cr17Ni14Mo2, etc.
Spiral steel pipe is also known as: SSAW spiral seam welded steel pipe, SAW spiral welded pipe, LSAW large diameter LSAW steel pipe, spiral steel pipe, Cangzhou spiral steel pipe, Hebei spiral steel pipe, Hebei steel pipe, Cangzhou spiral steel pipe, spiral pipe, spiral wound steel pipe) , Seamless steel pipe (seamless pipe), ERW longitudinal seam steel pipe (longitudinal welded pipe), hot rolled steel pipe, thermally expanded steel pipe, welded steel pipe, galvanized steel pipe, galvanized pipe, penstock, anticorrosive steel pipe, thermal insulation steel pipe (oil and gas 2PE/3PE polyethylene anti-corrosion layer, FBE dissolved epoxy powder steel pipe anti-corrosion, epoxy coal tar as paint, steel pipe cement mortar lining anti-corrosion, black and yellow jacket insulation steel pipe, flange, elbow, big bend, tee, big and small pipe fittings Our company can undertake single-layer and double-layer fusion bonded epoxy powder (FBE), double-layer polyethylene (2PE) and triple-layer polyethylene (3PE), double-layer polypropylene (2PP), and three-layer steel pipe Polypropylene (3PP), epoxy coal tar pitch anticorrosive paint and other pipeline external anticorrosion projects and IPN8710 polymer anticorrosive coating anticorrosion, cement mortar pipeline inner wall anticorrosion and other pipeline anticorrosion projects with multiple anticorrosive structures. Implementation of DIN30670, DIN30671, SY /T4013-2002, SY/T0315-97 standards.
