Seamless steel pipes
have a hollow section and are used in large quantities as pipelines for conveying fluids, such as pipelines for conveying oil, natural gas, gas, water and certain solid materials. Compared with solid steel such as round steel, steel pipe has lighter weight when the bending and torsion strength is the same, and it is an economical section steel.
"ERW steel pipe
" is Electric Resistance Welding, abbreviated as ERW. It is used to transport oil, natural gas and other vapor and liquid objects. It can meet various requirements of high and low pressure. It currently plays a pivotal role in the field of transportation pipes in the world.
1. Different molding methods
The seamless steel pipe is a steel pipe perforated from a whole round steel without welds on the surface.
ERW steel pipe refers to a steel pipe that is bent and deformed into a round shape by a steel strip or a steel plate, and then welded to a steel pipe with seams on the surface. The welding method of ERW steel pipe is high-frequency induction heating, which uses high-frequency induction current to heat the edge of the formed coil, and uses squeeze rollers for extrusion welding.
2. The price is different
The price of seamless steel pipe is more expensive than ERW steel pipe and the quality is better. The price of seamless steel pipes of the same specification is generally about 30% higher than that of welded pipes, and the price difference for large diameters is even greater. The required stress of seamless steel pipes can be much higher, and welded steel pipes are generally about 10Mpa, so seamless steel pipes are more expensive.
3. Different application scope
Seamless steel pipes: general-purpose seamless steel pipes are rolled from ordinary carbon structural steel, low-alloy structural steel or alloy structural steel, and have the largest output. They are mainly used as pipelines for conveying fluids or manufacturing structural parts and mechanical parts, such as oil drills. Rods, automobile drive shafts, bicycle frames, and steel scaffolds used in building construction are made of steel pipes to make ring parts, which can improve material utilization, simplify manufacturing procedures, and save materials and processing man-hours.
ERW steel pipe: ERW longitudinally welded pipe is mainly used in water supply engineering, petrochemical industry, chemical industry, power industry, agricultural irrigation, and urban construction. For liquid transportation: water supply and drainage. For gas transportation: coal gas, steam, liquefied petroleum gas. For structural purposes: as piling pipes and bridges; pipes for docks, roads, and building structures.
ERW straight seam welded pipes are generally used as wire casings in the power industry. Performance characteristics: 100% ultrasonic testing of the base material to ensure the internal quality of the pipe body; no uncoiling-disc shearing process, base material pressure pit , Less scratches; After the stress is eliminated, the finished pipe basically has no residual stress; the weld seam is short, and the probability of defects is small; it can conditionally transport the moist sour natural gas; After the diameter is expanded, the geometrical size of the steel pipe is high; welding It is carried out in a straight line in the horizontal position after the forming is completed. Therefore, the control of staggered edges, slits, pipe diameter and circumference is better, and the welding quality is excellent.