Definition of seamless steel tube

Seamless hollow sections, a large number of channels for transporting fluids, such as the transportation of oil, natural gas, coal gas, water and some solid materials, pipes and so on. Steel pipe and solid steel bar, etc. compared to the same torsional strength in bending, lighter,which is an economic cross-section steel, widely used in the manufacture of structural parts and mechanical parts, such as drill pipe, automotive drive shafts, bicycle Rack and construction using steel scaffolding steel pipe manufacturing annular parts, can improve material utilization, simplify the manufacturing process, saving material and machining time, such as bearing rings, jack sets, has been widely used to make steel. Steel or a variety of conventional weapons indispensable material, barrel, barrel, etc. to make steel. By cross-sectional shape of the pipe can be divided into tube and shaped tubes. Since the perimeter of equal conditions, the maximum area of ​​a circle with a circular tube can carry more fluid. In addition, the circular cross section to withstand internal or external radial pressure, the force is uniform, so the vast majority of the pipe is pipe.

However, the tube also has some limitations, such as by plane bending conditions, the tube is not as good as square, rectangular tube bending strength, some of the farm skeleton, steel and wood furniture to common square, rectangular tube. According to different uses should also have other cross-sectional shapes of the shaped pipe.

Shoddy methods of identification
1. Shoddy seamless easily scratched because of shoddy seamless equipment is very easy to produce burrs, scratches steel surface. Deep scratches reduce the strength of steel.
2. Seamless shoddy no metallic luster, pale red color of iron or the like.
3. Shoddy seamless thin and low transverse ribs, a phenomenon often sufficient dissatisfaction, because the manufacturers to achieve large negative tolerance, finished the first few channels reduction is too large, iron-type small, hole filling dissatisfaction.
4. Shoddy seamless oval in cross section, because the manufacturers in order to save material and finished before the two rollers amount of reduction is too large, the strength of this seamless greatly decreased, and does not comply with seamless Dimensions standards.
5. Quality seamless uniform composition, high tonnage cold shear, cut head face smooth and neat, and seamless as shoddy material is poor, there are often cut off the meat head end of the phenomenon, that is uneven, and no metallic luster . And because less shoddy product manufacturers cutting head, head and tail will be a big ears.
6. Inferior seamless steel tube material containing impurities, the density of steel is small, and the size tolerance serious, so there is no case of a vernier caliper can check it for weighing. Generally the whole amount would be better proportionality, mainly taking into account the cumulative error and probability theory this problem.