Federal-Mogul Powertrain says it has developed a new process of welding gasket layers to ensure that seals remain intact.
The company claims to have overcome the sealing challenge on turbocharger outlet flanges where the gasket comprises multiple layers by blanking three holes out of the distance layer and creating three dimples in both of the sealing layers to ensure accurate location of the separate components.
The new process allows the functional outer layers to be spot-welded to each other directly through the dimples without affecting the material in the distance layer.
Problems can arise when welding multiple layers of stainless steel with aluminum-coated steel because the aluminum coating – added for corrosion resistance – can react during welding, resulting in bubbles that affect the sealing surface.
The new process has been in high volume production at the company’s sealing production site in Herdorf, Germany, for several months and Federal-Mogul says it has so far proven successful. The company is investigating whether the process can be transferred to other applications where functional gasket layers are combined with a coated distance layer or heat shield, on both gasoline and diesel engines.
“There is a known product quality challenge arising from the use of turbocharger gaskets made from a number of layers,” said Thorsten Schäfer, global engineering manager, rigid heat shields, Federal-Mogul Powertrain.
“When stainless steel and aluminum-coated steel are welded together a reaction can occur that compromises sealing integrity in the finished part. A recent design optimization opened the door for this new welding manufacturing process thereby eliminating the issue.”
November 10, 2015