Production technology of spiral steel pipe
Production technology of spiral steel pipe
(1) raw materials that are with coil, welding wire, flux. In the investment before going through rigorous physical and chemical testing.
(2) with steel head and tail docking, the use of single or double wire submerged arc welding, rolled into steel pipe after the use of automatic submerged arc welding.
(3) before forming, the strip through the leveling, cutting edge, planing edge, surface cleaning and delivery to the edge of the treatment.
(4) the use of electrical contact pressure gauge on both sides of the conveyor to control the pressure of the cylinder to ensure the smooth delivery of the strip.
(5) the use of external control or internal control roll forming.
(6) the use of 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 are used in the United States Lincoln welding machine for single or double wire submerged arc welding, in order to obtain a stable welding quality.
(8) Welded welds are subjected to continuous ultrasonic automatic wounds inspection, to ensure that 100% of the spiral weld nondestructive testing coverage. If there is a defect, automatic alarm and spray marking, production workers at any time to adjust the process parameters, the timely elimination of defects.
(9) using the air plasma cutting machine to cut the steel pipe into a single.
(10) cut into a single steel pipe, each batch of steel pipe must be a strict first inspection system, check the weld mechanical properties, chemical composition, melting conditions, steel pipe surface quality and after nondestructive testing to ensure that the pipe process qualified Before they can be put into production.
(11) Where there is a continuous acoustic flaw mark on the weld, after manual ultrasonic and X-ray review, if there is a defect, after repair, again after the nondestructive test until the defect has been confirmed.
(12) The butt welds of the strip and the pipe of the dies which intersect with the spiral weld are all inspected by X-ray or film.
(13) each pipe through the hydrostatic test, the pressure using radial seal. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device. Test parameters are automatically printed.
(14) pipe end machining, so that the vertical face, bevel angle and blunt edge to be accurately controlled.
Weld treatment
The spiral steel pipe is fed into the welded pipe unit, rolled by the multi-way roll, the strip is gradually rolled up to form the circular tube with the opening gap, the reduction of the squeeze roller is adjusted so that the gap gap is controlled at 1 ~ 3mm, and make the ends of the weld flush.
1. If the gap is too large, resulting in reduced near-effect, eddy current heat, weld inter-crystal joint failure caused by non-fusion or cracking.
2. If the gap is too small is caused by the adjacent effect increases, welding heat is too large, resulting in weld burning; or weld by extrusion, rolling after the formation of deep pit, affecting the surface quality of the weld.
After the two edges of the tube are heated to the welding temperature, the common metal grains are formed to penetrate and crystallize together under the extrusion of the squeeze roll to form a firm weld. If the extrusion force is too large, the metal in the molten state will be squeezed out of the weld, and if the extrusion force is too large, the metal will be squeezed out of the weld. If the extrusion force is too large, Not only reduces the weld strength, and will produce a lot of internal and external burrs, and even lead to welding and other defects.
(2) with steel head and tail docking, the use of single or double wire submerged arc welding, rolled into steel pipe after the use of automatic submerged arc welding.
(3) before forming, the strip through the leveling, cutting edge, planing edge, surface cleaning and delivery to the edge of the treatment.
(4) the use of electrical contact pressure gauge on both sides of the conveyor to control the pressure of the cylinder to ensure the smooth delivery of the strip.
(5) the use of external control or internal control roll forming.
(6) the use of 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 are used in the United States Lincoln welding machine for single or double wire submerged arc welding, in order to obtain a stable welding quality.
(8) Welded welds are subjected to continuous ultrasonic automatic wounds inspection, to ensure that 100% of the spiral weld nondestructive testing coverage. If there is a defect, automatic alarm and spray marking, production workers at any time to adjust the process parameters, the timely elimination of defects.
(9) using the air plasma cutting machine to cut the steel pipe into a single.
(10) cut into a single steel pipe, each batch of steel pipe must be a strict first inspection system, check the weld mechanical properties, chemical composition, melting conditions, steel pipe surface quality and after nondestructive testing to ensure that the pipe process qualified Before they can be put into production.
(11) Where there is a continuous acoustic flaw mark on the weld, after manual ultrasonic and X-ray review, if there is a defect, after repair, again after the nondestructive test until the defect has been confirmed.
(12) The butt welds of the strip and the pipe of the dies which intersect with the spiral weld are all inspected by X-ray or film.
(13) each pipe through the hydrostatic test, the pressure using radial seal. The test pressure and time are strictly controlled by the steel pipe hydraulic microcomputer detection device. Test parameters are automatically printed.
(14) pipe end machining, so that the vertical face, bevel angle and blunt edge to be accurately controlled.
Weld treatment
The spiral steel pipe is fed into the welded pipe unit, rolled by the multi-way roll, the strip is gradually rolled up to form the circular tube with the opening gap, the reduction of the squeeze roller is adjusted so that the gap gap is controlled at 1 ~ 3mm, and make the ends of the weld flush.
1. If the gap is too large, resulting in reduced near-effect, eddy current heat, weld inter-crystal joint failure caused by non-fusion or cracking.
2. If the gap is too small is caused by the adjacent effect increases, welding heat is too large, resulting in weld burning; or weld by extrusion, rolling after the formation of deep pit, affecting the surface quality of the weld.
After the two edges of the tube are heated to the welding temperature, the common metal grains are formed to penetrate and crystallize together under the extrusion of the squeeze roll to form a firm weld. If the extrusion force is too large, the metal in the molten state will be squeezed out of the weld, and if the extrusion force is too large, the metal will be squeezed out of the weld. If the extrusion force is too large, Not only reduces the weld strength, and will produce a lot of internal and external burrs, and even lead to welding and other defects.
Abstract from Tianjin Xinyue Steel Group
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