Patent GB-1398904-A (GB)
Title: Methods and apparatus for making edgelay multimetal components
IPC: B23K9/23
Filed: 1972-06-05
Abstract: 1398904 Making edgelay multimetal components; welding by fusion TEXAS INSTRUMENTS Inc 5 June 1972 [11 June 1971] 26156/72 Headings B3A and B3R [Also in Division F4] A method of making an edgelay multimetal component 84, 86 having opposite lateral edge portions of different thermal expansion properties comprises, holding metal elements or strips 46, 50 having substantially the same thermal expansion properties in edgewise abutting engagement with the edges of a central metal element or strip 48 of different thermal expansion properties, welding the engaged edges by tungsten inert gas (e.g. helium) welding to form an edgelay multimetal material 82 and dividing the material 82 longitudinally into the components 84, 86. The strips 46, 50 are of a Ni-Fe alloy and the strip 48 is of a Ni-Cr-Fe alloy having a higher coefficient of thermal expansion The strips are fed to a guide means 52, where they are brought into lateral abutment, Fig. 2 (not shown), and then passed over guide rolls 26, 28 and tensioning roll 36 to a heat sink roll 42, preferably passing through further guide means 52. The strips are located on the rolls 42 by a resiliently biased guide bar 70, Fig. 3, which pushes the strip 46 against a shoulder 42.3. The roll 42 is preferably of cast iron, but it may be of copper alloy, and is provided with passages for water or other coolant. 'Conventional tungsten inert gas welding torches 72, 74 are adjustably mounted in alignment with grooves 42.4 in the roll 42, thereby preventing welding of the strips to the roll. The cooling effect of the roll 42 prevents excessive width of the welds 90, 92. The welding torches are arranged in close proximity to each other so that the strips 46, 50 and the strip 48 are at substantially the same temperature during welding and thermal expansion of the strips 46, 50 is the same thereby avoiding excessive distortion of the multimetal material 82 on cooling. Desirably, a hood 80 is provided for removal of welding fumes. The apparatus may be modified by the provision of a further roll (42), Fig. 6 (not shown), which rotates in the opposite direction to the original roll 42, and torches (72), (74) weld the opposite face of the material 82, the previously welded face being in contact with the roll (42). Inert gas is supplied to the grooves 42.4 and to the corresponding grooves in the roll (42), to provide additional shielding of the welds, Fig. 7 (not shown). The cooling of the rolls 42, (42), may be adjusted to provide some heating of the strips prior to welding. Additional cooling of the weld area may be effected by bevel edged rolls (110) made of heat-conducting material, e.g. copper, Fig. 9 (not shown), engaging the strip surfaces in the vicinity of the welding zone. In an alternative method the starting material may comprise two-layer thermostatic bimetal strips (46a), (48a), (50a), Fig. 10 (not shown). The strips (46a), (50a) are fed from the reels 14, 18, Fig. 1, with the layer of lower expansion properties uppermost and the strip (48a) on the reel 16 is fed therefrom with the layer of higher expansion properties uppermost. In a further alternative method, additional strips (112), (114), Fig. 11 (not shown), e.g. of low carbon steel, are welded to the strips 48, 50 to form a five component composite material (116), which is slit longitudinally through the centre strip 48. Slitting is performed by a conventional two-roll slitter.