New welding method cuts material costs

#2/2009

Steel price hikes put pressure on ABB in Skien, Norway, when profitability for switchgear production dropped. A change of welding method solved the problem.

ABB Medium Voltage Products in Skien, Norway, manufactures gas-insulated switchgear for voltages of up to 36 kV. In 2007 costs of materials increased dramatically when commodity prices began to soar. The cost of the steel in the switchgear housings increased so much that ABB found it difficult to maintain competitive prices.

In order to reduce costs for the increasingly more expensive steel, ABB wanted to reduce its thickness from 3 to 2 millimetres without compromising the quality of the product or the welds.

If this could be achieved, abb would save on material costs and be able to offer competitive prices on an increasingly tough market. And if it proved possible to weld without spatter, there would be further opportunities for saving money, as spatter would mean extra grinding and polishing work. The housings also had to be completely gas-tight, so that there would be no risk of gas leaking.

“If we were successful, we would save a lot of money, thanks to lower material costs, and would continue to be competitive on a tough market,” recalls Nils Landsverk at ABB. “And being able to weld without spatter would save even more money.”

ABB had already been involved in a joint project with AGA for MIG welding. The assignment then had been to introduce RAPID PROCESSING® welding technology for use on 304 grade stainless steel. The results had been very successful, and ABB had achieved considerable savings in costs.

In the summer of 2007, ABB turned once again to AGA with its next challenge – gas-tight housings.

“I suggested that we should try and solve the problem by changing the welding method and use TIG welding instead,” explains Helge Bergfjord, technical specialist at WELDONOVA®.

Together with AGA’s welding experts, a number of tests were carried out at AGA’s welding laboratory in Stockholm. Satisfactory results were soon reached, and the team decided to adopt the tig welding method.

“We invested in new tig equipment, and when we started up production we soon achieved good results – the housings were airtight and without deformities,” says Landsverk. “The weld itself was smooth and spatter-free.”

It was also possible to maintain the already high welding rate.

The same housings are still being made, but the steel walls are now 1 millimetre thinner. And the same functional guarantees still apply, i.e., no gas leaks for at least 30 years.