The steel grades and specifications of steel pipe products are extremely diverse, and their performance requirements are also various. All of this should be differentiated as user requirements or working conditions change. Generally, steel pipe products are classified according to sectional shape, production method, pipe material, joining method, plating characteristics and use. Straight seam steel pipes can be divided into round steel pipes and special-shaped steel pipes according to the cross-sectional shape.
Shaped steel pipes refer to various steel pipes of non-circular cross section. The main ones are: square tube, rectangular tube, elliptical tube, flat elliptical tube, semicircular tube, hexagonal tube, hexagonal inner tube, unequal hexagon tube, equilateral triangle tube, pentagonal plum tube, octagonal tube, convex Shaped tube, double convex tube. Double concave tube, multi-concave tube, melon-shaped tube, flat tube, diamond tube, star tube, parallelogram tube, ribbed tube, drop tube, inner fin tube, twisted tube, B tube, D Type tubes and multilayer tubes.
Steel pipes are further divided into equal-section steel pipes and variable-section steel pipes according to the longitudinal section shape. The variable cross section (or variable cross section) steel pipe refers to a steel pipe which periodically or non-periodically changes in cross-sectional shape, inner and outer diameter, and wall thickness in the longitudinal direction of the pipe. The main ones are: outer conical tube, inner conical tube, outer step tube, inner step tube, periodic section tube, bellows, spiral tube, steel tube with heat sink and barrel with double line. Application range Straight seam steel pipe diameter range is between 406~1600mm, even larger under special circumstances, the ratio of pipe wall thickness to pipe diameter is between 0.06~0.08. Foreign modern pipe making technology can produce thick-walled steel pipes with wall thicknesses up to 100mm.
There are only a few methods for producing straight seam welded pipes by steel plates or steel strips in the industry. The difference in principle lies in the forming method of the steel pipes. The subsequent processing of the steel pipes after forming is basically the same. The forming method depends in principle on the distribution of the welds of the steel tubes, which are divided into two basic forms according to the distribution of the welds: lsaw steel pipe and ssaw steel pipe. Correspondingly, the production of welded pipes is divided into the production of straight welded pipes and the production of spiral seam pipes. The most widely used welding method for straight seam welded pipe and spiral seam pipe is submerged arc welding (SAW), which has good quality, high productivity, mature technology and stability.
What are the advantages and disadvantages of the straight seam steel pipe double-tube unwinding machine? The advantages of the straight seam steel pipe double-tube unwinding machine are that the equipment is stable, the operation is reliable, the mechanization is high, the unwinding speed is fast, and the edge of the straight seam steel pipe is in the straight seam. The steel pipe is not scratched, and the coil is allowed to have a small edge and a tower shape. The disadvantage is that the inner diameter of the straight seam steel pipe coil is less than the allowable value, and the transmission part of the bell jar and the clutch is weak, and cannot withstand the strong impact and vibration during the unwinding, and all the mechanical operations of the straight seam steel pipe unwinding are slow. The time for the preparation process is extended. Straight seam steel pipe double cylinder unwinding machine is suitable for small diameter and high speed straight seam steel pipe unit. It is also applicable to the backup side join stitching line.
How to calculate the required torque and motor power of the straight seam steel pipe unwinding machine? The unwinding motor of the transmission reel is installed on the straight seam steel cantilever single reel unwinding machine. The double-end unwinding machine of the straight seam steel pipe connecting the coiling work line is connected to the motor of the winding of the drive reel in the side shaft end of each reel. When the unit suddenly decelerates or suddenly stops due to an accident, the motor brake can be started.
The sealing performance of the cement pipe is very poor. The concrete pipe of the domestic flat interface is only sealed by a circle of concrete at the joint. It is difficult to ensure no leakage during construction. In addition, the concrete pipe is rigid and slightly moved (such as uneven soil settlement). The joint is damaged. In addition, the cement pipe is sealed with a vulcanized rubber ring. The plastic pipe is sealed with a thermoplastic elastomer seal. The service life of the former is shorter than the latter, and the connection and sealing of the plastic pipe have a series of strict requirements, which can ensure maximum guarantee. No leaks will occur. The life of cement pipes is only 15 years, and the life of plastic pipes is 50-100 years. Domestic sewage, rainwater, etc. are generally corrosive, and industrial sewage is more corrosive. It is transported using metal and cement buried drain pipes, and the corrosion resistance is worse than that of plastic pipes.
In some areas, the outdoor natural environment is very corrosive. For example, the Tianjin Tanggu New Area is built around the sea. The cement sewage pipes laid down cannot be found after 3 years. They are all corroded by the salt in the seawater, so they have to lay the plastic pipes twice.