ESAB Africa Welding and Cutting has won the DCD Wind Towers contract to supply a turnkey welding and cutting system for South Africa’s first wind tower plant in Coega, Eastern Cape.
The supply contract – comprising a turnkey welding and cutting solution; and a growing line capable of producing towers 120m long – will be completed through ESAB’s BBBEE channel partner, Xeon Gas and Welding.
ESAB Africa marketing director, Kim Brightwell, says the company is the only original equipment manufacturer capable of supplying the total solution to fabricate wind towers.
“Wind tower fabrication is a technology in which ESAB has specialised internationally, and we have success stories all over the world. The Coega plant is backed by all this knowledge and experience in a state-of-the-art total solution,” he says.
The system will enable the new R300m operation to cut plate, roll it into “cans” and then weld the cans until the required section length is achieved.
“ESAB-design roll beds are used to ‘grow’ the line. A set of hydraulically-driven transfer rollers lift the ‘can’ clear of the rotating rollers and shuffle it along and onto a rollerbed further down the line,” Mr Brightwell says.
A new can is loaded and welded, before the whole weldment is shuffled up another 3m. In the end the line produces a complete tower section of up to 38m in length on a single growing line – DCD Wind Towers will have four of these lines.
“This new ESAB method has completely replaced the outdated approach to making wind towers using cranes. No cranes are used in the ESAB process.”
ESAB and XEON Gas and Welding have developed process handling solutions from the moment steel plate arrives at the factory, until the final shot blasting and painting of the completed tower. The plate is cut using two ESAB SUPRAREX HD 6000 CNC-controlled flame cutting machines. Once profiled, the plate is rolled to form the ‘can’, and the longitudinal seam is closed at the first welding station.
“The root runs are completed from the inside at ground level, and the ‘can’ is the rotated through 180°, with the root weld completed with no back gouging. ESAB Aristo 1000 AC.DC submerged arc power sources are used for the welding operation, for more welding per kilowatt hour,” Mr Brightwell says.
The ESAB PEK controller, capable of storing up to 255 pre-programmed procedures, is used to manage the different welding procedures and parameters for each welding seam.