Spiral welded pipe (some people call it SSAW steel pipe) is also a kind of welded pipe, its strength is generally higher than the LSAW steel pipe. Spiral welded pipe with large diameter can be produced by the narrow blank, and SSAW steel pipe with different diameter can also be produced by the same width of blank. However, compared with the same length of the straight pipe, the weld length increased by 30 to 100%, and the production rate is low. Therefore, the smaller diameter of the pipe mostly use LSAW steel pipe, large diameter welded pipe mostly use spiral welded pipe.
The production process of spiral welded pipe
Spiral welded pipe is the steel pipe with spiral seam that using the strip coil as raw material, extrusion forming under normal temperature, and using automatic double wire double-sided submerged arc welding process to weld.
1.Raw materials are coil, wire, flux. Those must finish the rigorous physical and chemical testing before putting into.
2.The head and tail of strip steel butt joint, use single or double wire submerged arc welding, and use automatic submerged arc welding to repair welding after rolled into steel pipe.
3.Before forming, the strip will go through the leveling, cutting edge, planing edge, surface cleaning and delivery to the edge of the treatment.
4.Using electrical contact pressure gauge control the pressure of the cylinder on both sides of the conveyor to ensure the smooth delivery of the strip.
5.Use external control or internal control roll forming.
6.Use weld gap control device to ensure that the weld gap to meet the welding requirements, diameter, misalignment and weld gap are strictly controlled.
7.Welding and external welding all use American Lincoln welding machine to single or double wire submerged arc weld, in order to obtain a stable welding specifications.
8.The welding line after welding must go through on-line continuous ultrasonic automatic injury inspection to ensure that 100% of the spiral weld non-destructive testing coverage. If there are defects, automatic alarm and spray marking, production workers adjust the process parameters at any time, eliminate of defects timely.
9.Use air plasma cutting machine to cut a single pipe.
10.After cutting into a single steel pipe, the first three of each batch of steel pipe must be carried out a strict first inspection system, to check the weld mechanical properties, chemical composition, melting conditions, steel pipe surface quality and after nondestructive testing to ensure that the pipe process qualified, so it can be put into formal production.
11.There are parts marked by ontinuous acoustic flaw on the seam, after manual ultrasound and X-ray review, if there are defects, after repair, again after the nondestructive test until the defect has been confirmed to eliminate.
12.The butt welds and helical welds of strip steel where the junction of the Ding-type joints, all through the X-ray TV or film inspection.
13.Each pipe must go through the hydrostatic test, the pressure using radial seal. Test pressure and time by the steel pipe hydraulic microcomputer detection device strictly controlled. Test parameters are automatically printed.
14.Pipe end machining, so that the vertical face, bevel angle and blunt edge to be accurately controlled.
