SSAW Pipe

 　　Causes of welding deformation of thin steel plate: 　　1. Analysis of welding deformation 　　Welding uses heat to connect two workpieces, but the heat will cause welding thermal deformation of the workpiece. When the workpiece is not uniformly heated, the stress is greater than the yield point of the material, and the workpiece will expand and contract, resulting in residual stress and residual deformation after cooling. 　　2. Welding deformation control 　　Using continuous spot welding instead of continuous welding can prevent and reduce the damage caused by welding deformation. In addition, the commonly used method is anti-deformation method, using assembly and welding sequence to control deformation, and using assembly and welding sequence to control deformation is also a good method , It is very beneficial for maintenance personnel to improve efficiency and reduce labor intensity. 　　3. The influence of welding sequence 　　After testing, using the same machine, operator, welding me...

 　　The internal and external anti-corrosion practices of spiral steel pipes (SSAW) should meet the requirements of the design institute and the owner. Generally, the internal and external anti-corrosion process of spiral steel pipes is as follows: base surface treatment, rust removal, welding slag → allocation of paint → intermediate paint → brush or spray construction → maintenance, no The anti-corrosion properties of spiral steel pipes are different in different application scenarios. The indexes of the internal and external anti-corrosion coatings of spiral steel pipes used for drinking water should meet the testing requirements of the Ministry of Health of the State for the hygiene and safety of drinking water. 　　1. Classification of external anti-corrosion practices for spiral steel pipes 　　(1) Indoor and outdoor exposed steel pipes and fittings 　　Use ordinary grade anti-corrosion. After the pipe surface is derusted and cleaned up, brush two coats of H53-22 epoxy iron red anti...

 　　The three-layer polyethylene (3PE) anticorrosive coating has been widely used in the petroleum pipeline industry due to its good corrosion resistance, water vapor permeability resistance and mechanical properties. This kind of anti-corrosion coating steel pipe end is prone to warping problems due to corrosion. 　　It is analyzed that when the 3PE anti-corrosion layer steel pipe is grinding the groove of the polyethylene layer of the reserved section, the weld height of the pipe end is not ground or the ground is uneven, which will cause the epoxy powder at the bottom of the polyethylene bottom of the welding seam to be abraded. When the anti-corrosion pipe is stacked in the open air for a long time, the surface metal of the weld will be corroded first, which will cause the phenomenon of warping of the 3PE anti-corrosion layer. 　　The measures to avoid warping at the end of the 3PE anti-corrosion layer are: 　　1. Under the condition of not affecting the welding of the nozzle, the res...

 　　Structural pipe is a general structural steel pipe, referred to as structural pipe. This standard applies to seamless steel pipes for general structures and mechanical structures, and the fluid seamless steel pipe standard applies to general seamless steel pipes that transport fluids. Structural pipes are steel pipes used to build various structures, because they are used to build various structures and need to achieve several characteristics. 　　1. The pressure-bearing capacity should be good, and no fracture should occur, otherwise the entire construction of the project will be affected if an accident occurs. 　　2. Convenient to build, just need to build according to general standards and it can be completed quickly. 　　3. Durable, it can be used for a long time after the project is completed, and it will not be damaged and worn for a long time. 　　Fluid pipes are steel pipes used to transport various liquids and gases such as oil, gas, natural gas, and water. Because it is used f...

 　　1. Lightweight, convenient transportation, and low construction cost: The seamless steel pipe has high construction strength and often requires auxiliary construction tools such as cranes. The density of PE water supply pipes is less than 1/8 of that of steel pipes (PE water supply pipes have a density of 0.935g/㎝3, steel pipes). It is 7.88 g/㎝3), the 315-size pipe weighs only 9.29kg, the construction intensity is low, the progress is fast, and the construction cost can be reduced by 30%-50% compared with traditional pipes; and with the shortage of steel in the market, its The price will continue to rise, so it's cost performance is self-evident compared with PE water supply pipes. 　　2. Corrosion resistance: The outer side of the steel pipe needs to be brushed with oil to prevent corrosion, which increases the project cost; the inner side of the steel pipe is susceptible to electrochemical corrosion and microbial corrosion and must be anti-corrosive. After long-term use, the zin...

 　　(1) When the height of the scaffold is less than 15m, it is calculated as a single-row scaffold; when it is greater than 15m or the area of doors, windows and decoration exceeds 60%, it is calculated as a double-row scaffold. 　　(2) For interior walls and enclosing walls with a height less than 3.6m, the calculation is based on scaffolding. When it is greater than 3.6m, it is calculated as a single row of scaffolding. 　　(3) When the stone masonry wall is higher than 1m, it shall be calculated according to the external scaffolding. 　　(4) Frame column beams are calculated according to double-row scaffolding. 　　(5) When the decorative surface of the indoor ceiling is less than 3.6m from the designed indoor floor, the full house scaffolding is used, and the wall decoration is no longer calculated. 　　(6) The masonry storage warehouse shall be constructed by double-row scaffolding. 　　(7) When the foundation of the storage tank, oil storage tank, and large equipment is larger than 1.2m,...

 　　After removing the root of the weld, double-sided weldments should be inspected. When using the oxyacetylene flame to cut the welding fixture on the alloy pipe that has a tendency to harden, defects in the ground part will be found. Radiographic testing and ultrasonic testing The main targets of radiographic testing and ultrasonic testing are the butt joints of straight seam steel pipes and the butt joints of butt welded pipe fittings. 　　The basis for selecting the non-destructive testing method of the straight seam steel pipe is the rule of the planning document. For welded joints of titanium, aluminum and aluminum alloys, copper and copper alloys, nickel and nickel alloys, radiographic testing methods should be used. For welds that are prone to cracks, radiographic and ultrasonic inspections should be performed after a certain period of time after the welds have cooled. 　　When the main pipe in the casing has a circumferential seam weld, the weld should be 100% radiographically...

 　　Characteristics of straight seam steel pipe: 　　Straight seam steel pipe generally refers to the use of a special process to carry out anti-corrosion treatment on ordinary steel pipes, so that the anti-corrosion ability of the steel pipe is generally used for waterproof, rust, acid and alkali resistance, and oxidation resistance. The process of the base material of the longitudinal seam anticorrosive steel pipe includes the submerged arc welded longitudinal seam steel pipe and the high-frequency longitudinal seam steel pipe. The diameter of anticorrosive submerged arc welded straight seam steel pipe(lsaw steel pipe) is above 325, and the diameter of anticorrosive high frequency straight seam steel pipe(erw steel pipe) is below 426. 　　Corresponding anti-corrosion measures are taken for the inner and outer walls of steel pipes according to different requirements and application environments. The common ones are mainly epoxy coal tar anticorrosive steel pipe, polyurethane coating an...

 　　1. Drainage pipe fittings are not flowing downstream. 　　No downstream fittings are used at the elbow and tee, which increases the water flow resistance. Or the water from the two outlets of the drainage horizontal pipe flows in opposite directions to the tee between the two outlets and is discharged from the side socket of the tee. The disadvantage is not only that the water flow is not smooth, but the slope of the pipe section is unreasonable and easily blocked. It is advisable to change this “head T” approach to elbow plus water tees (whether it is changed to Y tee or TY tee) and stagger to avoid that the drainage of different directions meets orthogonally on the plane. 　　2. There is no gap in the flexible connection of cast iron pipe joints. 　　The process stipulates that there should be a gap of about 10mm between the sockets to facilitate expansion and contraction. In the operation, this point is often ignored and the sockets are pressed to death. Marks should be made in adv...