Commonly used spiral pipe materials in China generally include: Q235A, Q235B, Q345, L245, L290, X42, X52, X60, X70, X80, 0Cr13, 1Cr17, 00cr19ni11, 1Cr18Ni9 and 0cr18ni11nb. Common standards for spiral pipes are generally divided into: SY / t5037-2018 (ministerial standard, also known as spiral seam submerged arc welded steel pipe for ordinary fluid transmission pipeline), GB / T9711.1-1997 (national standard, also known as technical delivery conditions of transmission steel pipe for oil and gas industry, part I: class a steel pipe (GB / t9711.2 class B steel pipe with strict requirements)), api-5l (American Petroleum Association, also known as pipeline steel pipe); Including PSL1 and PSL2), SY / t5040-92 (spiral submerged arc welded steel pipe for pile). (1) raw materials, i.e. strip steel coil, welding wire and flux. Strict physical and chemical inspection shall be carried out before input (2) The butt joint of strip steel head and tail adopts single wire or double wire submerged arc welding, and automatic submerged arc welding is adopted for repair welding after rolling into steel pipe (3) Before forming, the strip steel is leveled, trimmed, planed, surface cleaned, transported and pre bent (4) The electric contact pressure gauge is used to control the pressure of the pressing oil cylinder on both sides of the conveyor to ensure the smooth transportation of strip steel (5) Adopt external control or internal control roll forming (6) 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 (7) Both internal welding and external welding adopt American Lincoln Electric welding machine for single wire or double wire submerged arc welding, so as to obtain stable welding specifications (8) All welded welds are inspected by on-line continuous ultrasonic automatic flaw detector to ensure 100% NDT coverage of spiral welds. If there are defects, it will automatically alarm and spray marks, and the production workers will adjust the process parameters at any time to eliminate the defects in time (9) The steel pipe is cut into single pieces by air plasma cutting machine (10) After cutting into a single steel pipe, each batch of steel pipe shall be subject to a strict first inspection system to check the mechanical properties, chemical composition, fusion condition, surface quality of steel pipe and NDT to ensure that the pipe making process is qualified before it can be officially put into production (11) The parts with continuous acoustic flaw detection marks on the weld shall be rechecked by manual ultrasonic and X-ray. If there are defects, after repair, they shall be subject to NDT again until it is confirmed that the defects have been eliminated (12) The pipe of butt welding seam of strip steel and T-joint intersecting spiral weld shall be inspected by X-ray television or film (13) Each steel pipe is subject to hydrostatic test, and the pressure adopts radial seal. The test pressure and time are strictly controlled by the microcomputer detection device of steel pipe water pressure. Test parameters are automatically printed and recorded (14) The pipe end is machined to accurately control the perpendicularity, slope angle and blunt edge of the end face. Spiral seam submerged arc welded pipe for pressure fluid transportation is mainly used for pipelines transporting oil and natural gas. The steel pipe has strong pressure bearing capacity and good plasticity, which is convenient for welding and processing; Spiral seam submerged arc welded steel pipe for general low-pressure fluid transmission is made of double-sided automatic submerged arc welding or single-sided welding method, which is used for general low-pressure fluid transmission such as water, gas, air and steam.

Straight seam welded pipe has the advantages of simple production process, high production efficiency, low cost and rapid development. 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. Therefore, straight seam welding is mostly used for small-diameter welded pipes, and spiral welding is mostly used for large-diameter welded pipes. Spiral pipe is mainly 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, drainage, sewage treatment engineering, mud transportation, marine water transportation. For gas transmission: gas, steam and liquefied petroleum gas. For structure: as pile driving pipe and bridge; Pipes for wharf, road and building structures, marine piling pipes, etc.