Submerged arc welding steel pipe: spiral seam steel pipe is welded by automatic double-wire and double-side submerged arc welding process, which is made of strip coil plate as raw material and formed by constant temperature extrusion. Characteristics of submerged arc welded steel pipe: straight seam welded pipe production process is simple, has high production efficiency, low cost, and rapid development. The strength of spiral welded pipe is generally higher than that of straight seam welded pipe. It can produce welded pipe with larger pipe diameters with narrow blanks, and it can also produce welded pipe with different pipe diameters with blanks of the same width.

Compared with the straight seam pipe of the same length, the weld length of spiral submerged arc welded steel pipe is increased by 30~100%, and the production speed is lower. Therefore, straight seam welding is mostly used for small-diameter welded pipes, and spiral submerged arc welding is mostly used for large-diameter welded pipes.

Submerged arc welding steel pipe production process:

(1) The raw material is strip coil, welding wire, and flux. They must undergo rigorous physical and chemical tests before they are put into use.

(2) Single-wire or double-wire submerged arc welding is used for the butt joint of the strip steel head and tail, and automatic submerged arc welding is used for repair welding after rolling into the steel pipe.

(3) Before forming, strip after leveling, cutting edge, planing edge, surface cleaning transport, and bending treatment.

(4) The electric contact pressure gauge is used to control the pressure of the cylinder on both sides of the conveyor to ensure the smooth transmission of the strip.

(5) External control or internal control roller forming.

(6) The weld gap control device is used to ensure that the weld gap meets the welding requirements and that the pipe diameter, the amount of the wrong edge, and the weld gap are strictly controlled.

(7) Lincoln welding machine of the United States is used for single-wire or double-wire submerged arc welding for internal and external welding, so as to obtain stable welding specifications.

(8) All welded welds have been checked by an online continuous ultrasonic automatic damage instrument, which ensures 100% nondestructive testing coverage of spiral welds. If there is a defect, automatic alarm, and spraying mark, production workers can adjust the process parameters at any time according to this, and eliminate the defect in time.

(9) The air plasma cutting machine is used to cut the steel pipe into single roots.

(10) After cutting into a single steel pipe, each batch of three steel pipe heads shall be subjected to a strict first inspection system to check the mechanical properties of the weld, chemical composition, melting status, the surface quality of the steel pipe, and nondestructive testing to ensure that the pipe making process is qualified before being formally put into production.

(11) The part with continuous acoustic flaw detection mark on the weld shall be reexamined by manual ultrasonic and X-ray. If there is any defect, it shall be reinspected by a non-destructive test after repair until it is confirmed that the defect has been eliminated.

(12) The butt weld of strip steel and the tube where the D-joint intersects with the spiral weld are located shall be inspected by X-ray television or film.

(13) Each steel pipe is subjected to the hydrostatic test, and the pressure is radial sealed. The test pressure and time are strictly controlled by the microcomputer testing device for steel pipe water pressure. Test parameters are automatically printed and recorded.

(14) Pipe end machining, so that the end perpendicularity, groove Angle, and blunt edge can be accurately controlled.

Cangzhou Shenlong Pipe Manufacturing Co., Ltd. produces large diameter spiral steel pipe, straight seam welded pipe, the company has passed the ISO9001R certification, and the whole product is tested according to the standard, recently our company has just delivered a batch of spiral steel pipe, used in the Philippines water supply project, the specification is DN200-DN1400, hope that more customers choose our products. We will try our best to serve every customer and deliver every order.