Monday, September 22, 2014

The difference between the spiral welded and straight seam welding

Welded pipe is a gas pipeline in the common pipe, diameter greater than 426mm (or 508mm) of the pipe is generally known as large-diameter pipe, welded pipe in accordance with the way, can be divided into two kinds of spiral welded pipe and ERW.

Spiral welded pipe is carbon steel or low carbon alloy steel strip at a certain helix angle (also known as molding angle) rolled into a tube, and the tube seam welded steel, it can be used a narrower the production of large diameter steel pipe. Mainly spiral submerged arc welded spiral pipes (SSAW), widely used in the construction of various gas pipeline, with a diameter * thickness specifications indicated. There are one-sided spiral pipe welding and double-sided welding, pipe should ensure that hydrostatic test, weld tensile strength and performance of cold-formed to meet the requirements.

Longitudinal is hot rolled coil after molding machine, so that the coil is deformed into a sleek cylindrical, using high-frequency current skin effect and proximity effect or solder layer under the burning arc welding, so that the tube Edge heating and melting, and to a certain compressive force under the action of the fusion, the final cooling of the molding. Which use high-frequency current to melt the edge of the tube is called high-frequency welded pipe (ERW), using arc melting is called LSAW pipe (LSAW).

Longitudinal main raw material is low carbon steel hot rolled coil, hot-rolled, in petroleum, metallurgy, construction, mining, port, machinery and other industries widely used in oil and natural gas, low water gas transportation, mining fluid transport, belt conveyor roller, automotive transmission and so on.

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