ERW - Electric Resistance Welded Pipe

For pipes or tubes size 14 inch (355.6mm) OD and below, the strip is fed into a set of forming rolls which consist of horizontal and vertical rollers so placed gradually from the flat strip into a tube which is then allowed to pass the welding electrodes. The electrodes are copper disks connected to the secondary of a revolving transformer assembly.

The copper disk electrodes make contact on each side of the seam and the temperature is raised to the welding point. The outside flash is removed by a cutting tool as the tube leaves the electrodes, inside flash is removed either by an air hammer or by passing a mandnel through the welded tube after the tube has been cooled.

This is termed an Electric Resistance welded or ERW tube/pipe. If this ERW is being drawn further to get the desired size of tubes or pipes, in cold conditions is called a Cold Drawn welded or CDW.

SAW - Submerged Arc Welded Pipe

This process is used for pipes from 16" to 36" i.e 406mm to 914mm OD. The flat plate is first pressed into U and later O shape.

The O shape is placed in an automatic welder and backed up on the inside by a water-cooled copper shoe. Two electrodes in close proximity and used. The electrodes are not in actual contact with the pipe. The current passes from on electrode through a granular flux and across the gap in the pipe to the second electrode. The high temperature of the arc heats the edges of the plate, a welding rod placed just over the seam is thereby melted and metal is deposited in the groove.

After the outside weld has been made, the pipe is conveyed to an inside welder where a similar operation is carried on, except that no backup shoe is needed.

Commonly used spot welding, seam welding, and butt three.

Cangzhou Shenlong Pipe Manufacturing Co., Ltd. is a high-tech enterprise specializing in the manufacture and sales of straight seam welded pipe and spiral steel pipe. The main products of the company are oil and gas bushing, tubing, pipeline pipe, pile pipe and structural pipe, etc., with an annual design capacity of 100,000 tons. The company's products execute API SPEC 5CT, API SPEC 5L, FM 1630, UL 852, JIS G3444, JIS G3452, ASTM A53/A53M, AS/NZS 1163, AS/NZS 1074, AS/NZS 1396 , EN10217, EN10219, EN10255 and GB/T9711, GB/T3091, and other domestic and foreign standards. Products are exported to overseas markets, widely used in petroleum, natural gas, solar energy, shipbuilding, automobile, chemical, environmental protection, boiler, fire protection, water conservancy, electrical industry, machinery and equipment, steel structure, construction and other industries.