Both the spiral steel pipe and the straight seam steel pipe belong to the series of welded steel pipes, and the number of applications is very large, but the spiral steel pipe has a greater advantage than the straight seam steel pipe in terms of price.
At present, the price of the mainstream spiral steel pipe in the market is about 2,000 yuan/ton, and the price of the straight seam steel pipe of the same specification is about 2,400 yuan/ton. It can be said that the price of the spiral steel pipe is lower. What kind of specifications are used in the project mainly depends on the design requirements. Let’s compare the spiral steel pipe and the straight seam steel pipe.
The left side of the above two products is a spiral steel pipe, and the right side is a straight seam steel pipe. The welding seam of the spiral steel pipe is a spiral shape, and the welding seam of the straight seam steel pipe is a straight line.
The straight seam steel pipe is a hot-rolled coil formed by a forming machine, and the edge of the tube blank is heated and melted by the skin effect and the proximity effect of the high-frequency current, and the steel pipe is produced by pressure welding under the action of the extrusion roller.
Spiral steel pipe is a spiral seam steel pipe made of strip steel coil as raw material, often warmly extruded, and welded by automatic double-wire double-sided submerged arc welding process.
The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe.
The welding seam of the spiral submerged arc welded pipe is spirally distributed, and the welding seam is long. Especially when welding under dynamic conditions, the welding seam leaves the forming point before cooling, and it is easy to produce welding hot cracks. The direction of the crack is parallel to the weld and forms a certain angle with the axis of the steel pipe, generally between 30-70°. This angle is just consistent with the shear failure angle, so its bending, tensile, compressive and torsional performance is far inferior to that of the straight seam submerged arc welded pipe. beautiful. In addition, during the construction process, the intersecting line weld at the node of the spiral welded parent pipe split the spiral seam, resulting in a large welding stress, thus greatly weakening the safety performance of the component. Therefore, the non-destructive testing of the spiral welded pipe weld should be strengthened. Ensure the welding quality, otherwise the spiral submerged arc welded pipe should not be used in important steel structure occasions.
The straight seam steel pipe is welded under static conditions, the weld quality is high, the weld is short, and the probability of defects is small. The steel pipe is expanded through the whole length, with good pipe shape, accurate size, and wide range of wall thickness and pipe diameter. It is suitable for steel structures such as buildings, bridges, dams, and offshore platforms. Electric pole tower mast structure.
Spiral steel pipe is a kind of steel commonly used in industry, construction and other industries. Mainly used in water engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, urban construction.
Post time: Sep-09-2022