How Electric Welded Tube Is Made?


Steel pipes are long hollow tubes that are used for the variety of purposes. There are two main ways of producing steel pipes. Depending on the way of production, the result may be either a seamless or welded tube. While both cases involve working with raw materials, the seamless pipe is made via stretching the steel out into the tube. The electric welded tube is made differently.  In the nutshell, it is made by forcing the edges of steel together, then sealing them together with a weld. But let’s have a more detailed look at how electric welded tube is made. 


History of Welding Method of Producing Steel Pipes

With welded and seamless pipes being find anywhere from bicycle frames and refrigerators to plumbing systems and building construction nowadays, you may get an impression, that those steel tubes have been with us all the time. But, actually, the first method of producing steel pipes was introduced at the beginning of the 19th century. 

The development of welded steel tube dates back to 1815, when William Murdock invented a coal burning lamp system. Murdock used discarded muskets to join barrels together, in order to transport this lightning method to London. He continued using this makeshift continuous pipeline to transport coal gas until the lightning system proved successful enough to attract variety of inventors to create a new process of producing pipes. 

Approximately ten years later, a notable method of producing metal tubes had surfaced. In 1824 an American inventor James Russell patented his method of producing metal tubes both quickly and cheaply. A flat iron strip was heated until is became ductile, then using a hammer the opposite edges were folded together and welded. The tube was finished via passing it through a groove. Basically, Russell provided the method that simply continued evolving through years. 


Modern Method of Electric Welded Tube Production

While Russell’s method gave birth to welded tube manufacturing, welding methods evolved. Nowadays, there are two types of producing electric-resistance welded tubes: High Frequency Induction Welding and High Frequency Contact Welding. 

In the first type, the weld is transmitted to the material through a work coil. The work coil doesn’t contact the pipe. The electrical current is prompted into the pipe material through the magnetic fields that surround the pipe. Thanks to the high frequency induction welding it is possible to change the size of the pipe without leaving contact marks. 

In the second type, the weld is transmitted to the material through contacts that move on the strip. The weld is applied directly to the pipe, which makes this process more efficient than the previous one. The high frequency contact welding is suitable for manufacturing pipes with large diameters and high wall thickness.