HUNAN PRIME STEEL PIPE is the export gateway of SHINESTAR HOLDINGS GROUP.
We are dedicated in providing and exporting high performance-price ratio welded & seamless steel pipes and fittings covering various steel grades.
At Prime Steel Pipe, we believe that honest communication, expertise in our industry, and prompt execution lead to strong long-term relationships.
Scaffolding pipe is usually made up of LSAW steel pipe or ERW steel pipe, its process types include: hot rolled/hot expended, electric resistance/high frequency. It has a variety of specifications, according to the diameter it can be divided into: Φ3.0, Φ2.75, Φ3.25, Φ2.5. Its length also has a variety of specifications: half a meter in a specification from 1 to 6 meters; it can be processed in accordance with customer specifications. The thickness is generally 2.4--2.7 mm and the diameter is 48 mm. The surface is generally not handled, individually coated with anti-rust paint. The material scaffolding pipe is: Q195, Q215 or Q235. The implementation of standard of scaffolding pipe is: SY/T5768-95 and GB/T3091-2001.
Different types of construction use different scaffolding and formwork support. At present, the bridge support frame mostly uses bowl buckle scaffolding, but also uses door scaffolding. The main structure of the construction of scaffolding mostly uses scaffolding scaffolding, scaffolding pole vertical distance is generally 1.2 ~ 1.8m; span is generally 0.9 ~ 1.5m.
Adaptability of scaffolding pipe:
1) to build various forms of scaffolding, templates and other support frame; 2) assembly of bone frame; 3) to set up ramps, sheds, stands and other temporary structures; 4) for other kinds of scaffolding support, strengthen the bar.
According to whether there is a weld seam on pipe wall, construction steel pipe is divided into seamless steel pipe and welded steel pipe. Seamed steel pipe is also divided into spiral welded pipe and LSAW steel pipe according to the different kinds of weld seam. Both of those are used very commonly in the construction piling, structure, steel structure, load bearing, drainage and other aspects of the application. The material of construction steel pipe mainly includes carbon steel, stainless steel, and alloy steel. Among those material, carbon steel material application is the most extensive. The length of the steel pipe can be carried out length according to the requirements of customer, and also can be scattered feet. Construction seamless steel pipe can be divided into: hot-rolled seamless pipe, cold drawn tube, precision steel pipe, thermal expansion pipe, cold spinning pipe and extrusion pipe according to the production method. Hot-rolled tubes are used more in the construction industry.
In the production of ERW steel pipe, high frequency technology used by pipe manufacturer, other welding of important components, welding of alloy steel and welding of thick parts all require preheating before welding. The main roles of preheating before welding are as follows:
(1) Weld peheating can slow down the cooling rate after welding, which is conducive to the spread of diffusible hydrogen in the weld metal, and avoids producing hydrogen to result in cracking. At the same time, it also reduces the degree of hardening of the weld and heat affected zone and improves the crack resistance of the welded joints.
(2) Weld preheating can reduce the welding stress. Uniformly preheating or entirety preheating can reduce the temperature difference (also known as temperature gradient) between welds in the weld area. In this way, on the one hand it reduces the welding stress, on the other hand, it reduces the welding strain rate, which is help to avoid welding cracks.
(3) Weld preheating can reduce the restraint degree of the welded structure, especially to reduce the degree of restraint of the corner joint. With the increase of the preheating temperature, the crack rate decreases.
The choice of preheating temperature and interlayer temperature is not only related to the chemical composition of steel and electrode, but also to the rigidity of welded structure, welding method, ambient temperature and so on. It should be determined after considering these factors. In addition, the preheating temperature in the direction of the steel plate thickness uniformity and uniformity in the weld area, has an important impact on reducing the welding stress. The width of the local preheating should be determined according to the degree of restraint of the workpiece to be welded, generally it should be around the weld area three times the wall thickness, and is not less than 150-200mm. If the preheating is not uniform, not only does not reduce the welding stress, but also will appear to increase the welding stress situation.
So when Prime Steel Pipe manufactures ERW steel pipe or other welded pipe, we will take control of preheating temperature strictly, so that we can produce perfectly good carbon steel pipe.
Large diameter LSAW steel pipe with its big wall thickness, good material, stable processing technology, becomes the preferred pipe by largest domestic and foreign oil and gas transportation project. In the large diameter LSAW steel pipe welded joints, weld and heat affected zone are the most prone to produce a variety of defects, and welding undercut, pores, slag, not fused, not penetration, welding cracks are the main form of welding defects, and also are the origins those often make LSAW steel pipe produce quality accident. The quality control measures will be listed below, if you you are interested in the production process of LSAW steel pipe, you can click the hyper-link.
1.The quality control before welding:
1) First of all, pipe manufacturer should take control of the quality of raw materials, after passing the inspection, raw materials can formally enter the construction site. And pipe manufacturer resolutely put an end to the use of substandard steel. 2) The next is the management of the welding material. Checking whether the welding material is a qualified product, whether storage and baking system is implemented, whether the surface of the welding material is clean and no rust, and whether the electrode coating is intact, with mildew or not. 3) The next is the welding area cleaning management. Check the cleaning quality of the welding area, there shall not be water, oil, rust and oxide film and other dirt, which plays an important role to prevent the occurrence of external defects in the weld. 4) Finally, choosing the appropriate welding method, it should be implemented before the test welding, after welding principle.
2. The quality control during welding:
1) According to the welding process to review the specifications of the wire and flux is correct or isn't, to prevent the wrong welding wire and flux caused by welding quality accidents. 2) Monitor the welding environment, when the welding environment is not good (temperature below 0 ℃, relative humidity greater than 90%) pipe manufacturer should take appropriate measures after welding. 3) Checkout the groove size, including the gap, blunt edge, angle and wrong, etc. meet the process requirements or not before pre-welding. 4) Checkout the selected welding current, welding voltage, welding speed and other process parameters are correct or aren't in the submerged arc internal and external welding process. 5) Supervise the welding personnel in the submerged arc internal and external welding full use of the length of the pipe end of the arc plate to strengthen the internal and external welding arc plate use efficiency, which helps to improve the quality of pipe end welding. 6) Supervise the welding staff in the welding is the first clean up the slag, whether it has been completely handle joints, groove whether there is oil, rust, slag, water, paint and other dirt.