Large diameter spiral steel pipe is a general description, actually referring to spiral steel pipes with a diameter greater than 1 meter. Spiral steel pipe is made by bending steel strip and then welding, subject to experiments such as hydraulic pressure, bending, and flattening, having certain requirements on surface quality. Usually, the length of pipe is 12 meters, or other dimension required by clients. The specifications of the spiral steel pipe are expressed by the nominal diameter (mm). The nominal diameter is different from the actual. There are two types, ordinary steel pipe and thick wall steel pipe according to the specified wall thickness.
Spiral welding process is totally different with straight welding. A continuous full penetration metal inert gas weld overlay is used to rebuild or repair damage from wear, erosion, corrosion or cracking, or to enlarge the dimensions of a component on a mating part during spiral welding process. Usually, large diameter welded steel tube is made through such welding steps.
Large diameter spiral steel pipe application:
Spiral steel pipe is mainly used in tap water engineering, petrochemical industry, chemical industry, electric 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 use: for piling pipes and bridges; for docks, roads, and building structures.
The common materials for large spiral welded steel tube are as below:
Q235A,Q235B,Q23b,0Cr13,1Cr17,00Cr19Ni11,1Cr18Ni9,0Cr18Ni11Nb. Q345,L245,L290, X42, X46, X70, X80
1. Composition and Mechanical properties of commonly used carbon steel alloy steel.
2. Seemless steel pipe, welded pipe, etc.
3. A series international universal series, domestic series.