What is the difference between seamless carbon steel pipe and welded steel pipe
- Jan 24, 2019-
Seamless carbon steel pipe is now used in a very wide range of fields, such as construction, transportation and so on, the reason why seamless carbon steel pipe can be so many applications, must be the advantages of steel pipe itself and advantages.Compared with the ordinary steel tubes once used, seamless carbon steel tubes adopt a series of high-tech manufacturing techniques, and then have the excellent quality of seamless carbon steel tubes.
Everybody's familiar with welded pipes.Today I would like to introduce the difference between seamless carbon steel pipe and welded pipe.
First of all: the main thing is that their molding process is different.Common steel pipe, for example tap water conduit, it is to pass commonly flat plank classics bend hind welding rises, this kind of craft is simpler coarse, a weld can be found above after finished product processing.But the seamless carbon steel pipe is generally the molten steel through the annular slot overstock after stretching and other processing technology molding, in this process there is no weld.
In terms of performance, seamless carbon steel tube has a great improvement in bearing capacity compared with ordinary steel tube, so it is often used in high-pressure equipment.Such as the pipeline connection of hydraulic equipment.The welding seam of ordinary steel pipe is its weak link, and the quality of welding seam is also the main factor affecting its overall performance.
Spiral submerged arc welding
Spiral submerged arc welding as raw material is often warm extrusion molding, automatic double -sided wire submerged arc welding process.
The process is normally limited to the flat or horizontal-fillet welding positions (although horizontal groove position welds have been done with a special arrangement to support the flux).
Spiral submerged arc welding process performance:
(1) raw materials that strip, wire, flux. Must go through rigorous testing before being put into the physical and chemical.
(2) strip head and tail docking, using single or double wire submerged arc welding, in rolled steel by automatic submerged arc welding.
(3) Before molding, the strip after flattening, cutting, trimming, planing, surface cleaning and transportation to the curved edge treatment.
(4) the use of electrical contacts on both sides of the conveyor control the pressure cylinder pressure to ensure the smooth delivery of the strip.
(5) the use of internal or external control roll forming.
(6) the weld gap control device to ensure that the weld gap to meet the welding requirements, diameter, volume and the wrong side of the weld gap have been strictly controlled.
(7) the welding and soldering are used outside the United States Lincoln welding machine for single or double wire submerged arc welding, to obtain stable welding specifications.
(8) After welding the weld line continuous ultrasonic injury checked to ensure 100% coverage of non-destructive testing of spiral weld. If defective, automatic alarm and spraying tags, production workers so adjusting the process parameters, and remove defects.
(9) the use of air plasma cutting machine to cut a single tube.
(10) cut into a single pipe, the first three of each batch of steel to carry out strict inspection system, inspection of weld
mechanical properties, chemical composition, fusion status, steel surface quality and after NDT inspection to ensure that the process pipe after passing to formally put into production.
(11) there is a continuous sonic flaw marks the site of the weld, manual ultrasonic and X-ray review, if there are defects after repair again after destructive testing until confirmation defect has been eliminated.
(12) strip on the spiral weld seam and intersects with D-type connector where the pipe all through the X -ray television or film examination.
(13) each pipe hydrostatic test pressure radial seal. Test pressure steel pipe pressure and time by computer testing device
strictly controlled. Test parameters are automatically printed record.
(14) pipe end machining, so that the end vertical, blunt edge bevel and accurate control.
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Spiral seam double surface submerged arc steel pipes are used widely in many field,such as fluid,petroleum and natrual gas transportation.Also there are some STANDARDS of PRODUCTS.
• API Spec 5L Line pipeand steel pipe standard;
• BG/T 9711.1-1997 Delivery of petroleum and natrual gasindustrial transportation steel pipe Technical conditions Part 1 Grade-A Steel Pipe;
• GB/T 9711.2-1999 Delivery of petroleum and natrual gasindustrial transportation steel pipe Technical conditions Part 1 Grade-B Steel Pipe;
• SY/T5037-2000 Spiral submerged are welding steel pipe forlow-pressure fluid deliverypipe.