What's spiral welded pipe and its development direction
What’s spiral welded pipe and its application
Spiral welded pipe: the carbon structural steel or low alloy structural steel strips in a helical line certain angle (called forming angle) rolled into a tube, then the pipe joints are welded together. It can produce large diameter steel pipe with narrow steel band. The specification of that is expressed as outside diameter * wall thickness. The welded pipe shall conform to the requirements of hydraulic pressure test, the tensile strength and the cold bending property.
Spiral welded pipe is mainly used in water engineering, petrochemical industry, chemical industry, electric power industry, agricultural irrigation, urban construction. Used for liquid transport: water supply, drainage. For gas delivery: coal gas, steam, liquefied petroleum gas. For structural use: used in wharf, road, building structure and so on.
Development direction of spiral welded pipe
Due to the increasing pressure on the bearing capacity of the pipeline, the use of increasingly harsh conditions, and extend the service life of the pipeline as far as possible, so the main development direction of the spiral welded pipe is:
- Produce large diameter thick walled tube to improve the pressure resistance.
- Design and manufacture new structure of steel pipe, such as double layer spiral welded pipe with a thickness of half of the pipe wall. Not only the strength of that is higher than single layer with the same thickness, but also does not appear brittle failure.
- Develop new type of steel, improve the technical level of smelting process. Controlled rolling and residual heat treatment process are widely adopted in order to improve the strength and toughness of the pipe.
- Vigorously develop coating tube. For example, apply anti-corrosion layer on the inner wall of the pipe, which can prolong the service life, improve the smoothness of the inner wall, reduce the frictional resistance of the fluid, reduce the accumulation of wax and dirt, reduce the times of cleaning and reduce the maintenance cost.
The spiral welded pipe has played an important role in the transportation of gas. With the planning and construction of a number of major pipeline projects at home and abroad, spiral welded pipe and other high value-added products, show a good market competitiveness and greater market demand. In the development of the series of products, Most of today's enterprises are relatively slow, so we should develop high added value of spiral welded pipe for industrial applications as soon as possible.
Anti-corrosion spiral welded pipe technology
Because of the quality of the spiral welded pipe is relatively large, so it is necessary to pile up in the outdoor. But it will be difficult to avoid the sun and rain, so the rust problem has been plagued with storage time and conditions of spiral welded pipe.
Steel wire brush is mainly used to polish the surface of steel. Cleaning and preheating of spiral welded pipe can remove loose or tilt of the rust, welding slag etc. Hand tools descaling can reach Sa2 level and power tools descaling can reach Sa3 level. If the steel adhered on the surface of iron oxide solid, the effect of tool cleaning is not ideal, which is not up to the requirements of the construction of anchor depth of corrosion. Using solvent, emulsion, pickling clean the surface of the welded steel pipe to remove oxide skin, rust, old coating.
