Seam weld cover sealing is a resistance welding process used to join cover and seal ring materials of Kovar™ 29=Ni/17-Co/Bal Fe alloy, CTE of 6 PPM, with 1.27µ Au/Ni plate on top. The weld is an alloy of Kovar™ Au/Ni which is corrosive-resistance and compliant with MIL-STD-883 Test Method 1009 Salt Atmosphere. The Au/Ni plate Kovar™ material may be hydrogen fired by the materials supplier. No forming gas is required. There is no stringent cleanliness requirement.
Two conical shaped electrodes roll along the perimeter of the package where the cover and seal ring are the two faying surfaces. At the electrode point of contact, a low voltage electrical circuit is completed through the cover with I2R heating. As the electrodes travel on the seam, overlapping welds are formed for a gas-tight, hermetic seal.
Seam weld cover sealing is easily viewed. The cover is placed upon the seal ring with gravity maintaining the fit-up of the two faying surfaces. There are no special jigs, fixtures or fasteners required. Seam weld cover sealing is available from prototyping through high speed production rates sealing thousands of packages per hour.