Seamless steel pipe has better pressure capacity, strength is higher than ERW welded pipe. So it is widely applied in high pressure equipment, and thermal, boiler industries. Generally the welding seam of the welded steel pipe is the weak point, the quality affect overall performance.
Seamless pipe vs welded pipe
1. The difference in production process
Welded pipe: The steel plate or steel strip is used as raw material, and it is welded after being crimped by the unit and mold. According to different welding methods, it can be divided into straight seam welded pipe and spiral welded pipe.
Seamless steel pipe: It is made by cold rolling, cold drawing or hot extrusion production process using round steel perforation as raw material.
2. The difference on the outer surface
Welded pipe: The steel pipe has high precision, uniform wall thickness, high brightness inside and outside the pipe, and can be arbitrarily cut to length; it can be used as a thin-walled pipe.
Seamless steel pipe: The steel pipe has low precision, uneven wall thickness, low brightness on the inside and outside of the pipe, high cost of sizing, and there are pitting and black spots on the inside and outside that are not easy to remove. Usually the pipe wall is thick.
3. The difference in performance
Seamless steel pipes are much higher than welded pipes in corrosion resistance and pressure and high temperature resistance.
With the improvement of welded pipe manufacturing technology, the mechanical properties and mechanical properties are slowly approaching seamless pipes. In some aspects, welded pipes can replace seamless pipes.
4. The difference in price
The production process of seamless steel pipe is more complicated, and its price is more expensive than welded pipe.
5. The difference in application
Seamless steel pipe: It has a hollow section and is used as a pipeline for transporting fluids, such as pipelines for transporting oil, natural gas, gas, water and certain solid materials. Widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile transmission shafts, bicycle frames, and steel scaffolding used in construction. Steel pipes are used to make ring parts, which can improve material utilization, simplify manufacturing procedures, and save materials and processing. Working hours.
Welded pipe: its pressure-bearing performance is general, mainly used to transport water, oil, gas, air, and heating water or steam and other generally lower pressure fluids.
Tips: ASTM A53 covers seamless and welded steel pipe with nominal wall thickness. The surface condition is usually black and hot-dipped galvanized. ASTM A53 is produced mainly for pressure and mechanical applications, and is also used for transport of steam, water, gas line pipes.