GB1025762A - Improvements relating to bonding involving rubbing engagement of the workpieces - Google Patents

Abstract

1,025,762. Welding by pressure. CATERPILLAR TRACTOR CO. Oct. 22, 1962 [Oct. 23, 1961; July 9, 1962], No. 39900/62. Heading B3R. In bonding workpieces, a predetermined amount of energy is developed and rapidly applied to the common interface of the workpieces engaged in rubbing contact and the dissipation of the energy is ended without applying a separate braking force or decoupling the workpieces from the energy input. A workpiece 35, Fig. 1, is held in a chuck 18 on a shaft 14 rotatable by a belt drive from a motor 19 and carrying a number of disc weights 31 and a workpiece 36 is held in a chuck 24 carried on a spindle 22 keyed against rotation in bearings 12, 13 but movable towards the chuck 18 by a lever 26 connected to a pneumatic device 29. The chuck 18 is rotated to bring the spindle 14 to a predetermined speed and, the device 29 is actuated to bring the stationary piece 36 into contact with the piece 35 thus bringing the parts to bonding temperature and supplying upsetting pressure as the spindle 14 comes to rest, the motor having been stalled or switched off when desired speed is reached. The workpieces may be 1 inch diameter steel rods when with a speed of 2000-3000 r.p.m., a pressure of 8000-12,000 p.s.i. and an inertial mass of 80 lb. a bond is produced in 1 second. In another embodiment a workpiece 53, Fig. 3 (not shown), is clamped in a chuck 56 supported on a table 49 secured between posts 47 and a bar 57 extends from the chuck through a spindle 58 rotatable in bearings 59, the lower end of the bar being rotatably mounted in a collar 61 movable by a jack 62 to clamp and release the workpiece. A hydraulic motor 66 drives the spindle 58 and weights 68 secured to the chuck. A workpiece 54 is clamped by a jack 72 in an upper chuck 71 non-rotatably mounted in a head 52 slidable on the posts 47. Clamping of the lower workpiece causes the supply of fluid to the motor which rotates the chuck, an upper jack 81 meanwhile bringing the workpiece 54 close to the workpiece 53. When the predetermined speed is reached the motor is de-energized and a lower jack 82 brings the workpieces together and bonding is effected as the stored energy of the weights is dissipated. No molten material appears at the interface, a solid state bond being formed and the forces applied work the narrow heat affected zone resulting in an abrupt transition from grain not heat affected and grain refined by heat and pressure applied. The displaced material having circumferential flow lines exists in an inner zone about the interface and has an abrupt transistion to non-displaced material. The bond progresses towards the centre of the interface and rods may be bonded to plates with incomplete interfacial bonds. Parts of steel, aluminium, bronze or titanium may be bonded and parts of steel may be bonded to parts of nickel alloy or of aluminium bronze. Studs may be bonded to plates and a gas turbine wheel 93, Fig. 31 (not shown), of high temperature alloy is bonded to a titanium alloy washer 99 in turn bonded to a plain carbon steel shaft 96. To smooth flash during bonding a ceramic sleeve 121, Fig. 34 (not shown), is mounted on a chuck 123 to surround the workpieces 127, 128 and a ceramic plug 126 is mounted within the workpieces. The Specification refers to bonding metals or metalloids.