Bridge stent spiral pipe with a ton How to With the development of the industry, engineering for the use of the bridge stent with the spiral steel pipe put forward higher requirements, the reason why there will be thick-walled spiral pipe, because some need to transport the media generated Pressure is an ordinary spiral pipe can not afford, if you do a straight seam pipe or seamless steel pipe, it will greatly increase the cost of the project, if it is a dangerous medium, we increase the cost is inevitable, so the choice of pipe is According to the project needs to transport the media and media pressure will be determined. The strength of the spiral steel pipe used for bridge supports is generally higher than that of the large-diameter straight seam steel pipe, the pipe with larger diameter can be produced from narrower billets, and the pipes with the same diameter can be produced from the billets with the same width. But with the same length of straight pipe compared to the weld length increased 40 ~ 100%, and the production rate is lower. Cut into a single pipe, the first three batches of steel to be strict first inspection system, check the mechanical properties of the weld, chemical composition, the status of fusion, the surface quality of steel and nondestructive testing through maintenance, to ensure that the process of qualified pipe , Can formally put into production. Thick-walled spiral steel pipe production process is simple, high production efficiency, low cost, rapid development. There should be a certain channel between the stack and the stack of the thick-walled spiral steel pipe. The width of the inspection channel is generally about 0.5m. The width of the access channel depends on the size of the material and the transportation machinery. Generally, the stacking of the spiral steel pipe of 1.5 to 2m Height, manual work of no more than 1.2m, mechanical work of no more than 1.5m, stack width of not more than 10 meters Bridge bracket with spiral pipe.
Spiral steel pipe
used as a bridge type of steel pipe welding, production should find the best welding method for it in order to improve the production efficiency of spiral steel pipe. Let's see what's the best way to weld a Spiral Pipe. Welded steel pipe to clean the first step to clean the mouth of the oil, paint, water, rust, etc., and then according to the wall thickness of the groove, the thickness of the larger open, thin to open smaller (angle grinder), and then is right Product gap, the general electrode or wire diameter of 1 to 1.5 times, if you bevel inadvertently open big words can be appropriate to stay smaller. Point welding at least three o'clock, generally four points better work. Welded steel pipe should be half of the time welding, and the starting point of more than the lowest point of about one centimeter, so good from the opposite connector. If the pipe wall thickness, it should be stratified, at least two layers, the first layer of the entire weld before welding the second layer. Spiral steel pipe bridge bracket packaging refers to the convenience of transport or for the protection of spiral steel pipe to protect the outer layer of protection, the general spiral pipe packaging is mainly exported spiral pipe, because the export of spiral pipe is mainly go by sea, In order to facilitate the general loading and unloading packaging, spiral steel pipe packaging is mainly divided into the following forms: 1, bundle packaging, which is bundled, such as 219 spiral steel pipe, 7 bundles, 273 spiral steel pipe 7 bundles . Each bundle has a lifting strap at each end to facilitate lifting. 2, box-type packaging, is the use of angle steel, square tube, welded steel channel into a box, above the opening, the same size and container loading and unloading direct FCL loading and unloading.
Spiral steel pipe with a stent material that is coil, wire, flux. In the input before going through a rigorous physical and chemical testing. Steel head and tail butt, the use of single or double wire submerged arc welding, after rolling into the steel pipe using automatic submerged arc welding. Before forming, strip through the leveling, trimming, planing, surface cleaning and delivery to the processing and bending. The use of electrical contact pressure gauge control conveyor pressure on both sides of the pressure tank to ensure the smooth delivery of the strip. External control or internal roller molding. The use of weld gap control device to ensure that the weld gap to meet the welding requirements, pipe diameter, the amount of the wrong side of the weld gap have been strictly controlled. Internal welding and external welding are using the United States Lincoln welding machine for single-wire or double-wire submerged arc welding, to obtain a stable welding specifications. The weld was continuously inspected by ultrasonic online automatic continuous injury tester to ensure 100% helical weld nondestructive testing coverage. Using air plasma cutting machine cut the steel pipe into a single root. Cut into a single pipe, the first batch of three steel pipe to the first strict inspection system to ensure that pipe technology qualified, formally put into production. Weld on a continuous acoustic flaw detection site, after manual ultrasound and X-ray review. The pipe where the butt weld strip and the butt joint where the helical weld intersects are all examined by X-ray television or filming. Each pipe after hydrostatic test, the pressure radial seal. Test pressure and time by the steel pipe pressure computer testing device strictly controlled. Test parameters automatically print records. Tube end machining, the end face verticality, bevel angle and blunt edge to be accurately controlled.
Spiral steel pipe in the material level and the requirements of the weld on the choice is very important, here we will introduce it! Spiral steel pipe grade selection should be based on economic principles to determine the higher level of steel, the price is slightly more expensive, but Thinner; lower grade steel, the price is slightly lower, but need to be thicker, to be compared. From the station to the stop, according to changes in pressure to take two or three different wall thickness and take different wall thickness and take different grades of thick-walled spiral pipe, such as the outbound section of the use of higher grade pipe, into Sections of the lower grade selection of pipe, pipe costs account for about 25% of the total investment in the pipeline, so the selection should be careful plan. From the Xinjiang pipeline situation, the general take x60, x65, x70 is appropriate; x70 steel is still lack of welding experience, welding technology should be studied in advance. Spiral pipe and uoE straight pipe, according to API 5L (1990) standards, both can be used, but the actual statistics point of view, high pressure, large diameter, long distance pipe in the world, many months uos straight seam tube. As mentioned earlier, the accident in the pipeline is proportional to the total length of the weld (excluding the girth). The spiral weld is 1 / Mn "1 longer than the straight weld, where the spiral weld and Horizontal angle, such as take "= 45I, the length of the spiral weld straight weld length of 1.41 times. Therefore, in this respect, further study is needed on the internal stress of welded steel pipe which affects the serviceability of steel pipe. Therefore, eliminating the internal stress of welded steel pipe is the main measure to improve the performance. Next, we will understand why the anti-corrosion spiral steel pipe The internal stress of welding. Spiral steel pipe in the welding process, due to the high temperature of the spiral welded steel pipe, so that weld metal and heat affected zone changes in the organization of hand-grain coarsening, but also there is a great internal stress. Based on the results of these changes, the performance of the metal in the inflammation zone greatly differs from that of the base metal (pipe body). Spiral steel pipe because of cheaper prices, is currently widely used in water pipelines or some less pressure on the oil and gas industry. When the delivery of spiral pipe is a 12 meters. Seamless steel pipe wider range of applications, for demanding water pipelines, oil, natural gas pipelines, machinery industry, etc. can be applied seamless steel pipe. Seamless steel pipe delivery at the time there is no uniform length of the specific choice of what kind of steel according to the actual needs of the user or the Institute's requirements to purchase. The impact toughness of the spiral steel pipe for bridge supports is a measure of the resistance of metals to external shock loads and is generally expressed in terms of impact (ak) and impact energy (Ak) in units of J / cm2 and J (Joules), respectively. Impact toughness or impact energy test (referred to as the "impact test"), due to the different test temperature is divided into three kinds of room temperature, low temperature and high temperature impact test; if the sample notch shape can be divided into "V" notch and "U" Two types of notch impact test. Impact test: A test of a certain size and shape ("U" type or "V" notch in the middle in the longitudinal direction, notch depth 2 mm) was subjected to an experiment of breaking from a notch under impact load on a prescribed testing machine.