Abstract: A technique for resistance welding an attachment such as a collar or base ring to a tank head section by causing welding current to flow through weld protrusions disposed on the attachment and which are pressed against the tank section. Electrodes are contacted to the attachment and the tank section in such a manner to provide for substantially equal welding current paths through the protrusions.

Abstract: A capacitor discharge process for welding a braided cable formed from a plurality of individual cable strands to a solid metallic electrically conductive member comprises the steps of: (a) preparing the electrically conductive member for welding by bevelling one of its end portions while leaving an ignition projection extending outwardly from the apex of the bevel; (b) clamping the electrically conductive member in a cathode fixture; (c) connecting the electrically conductive member clamped in the cathode fixture to a capacitor bank capable of being charged to a preselected voltage value; (d) preparing the braided cable for welding by wrapping one of its end portions with a metallic sheet to form a retaining ring operable to maintain the individual strands of the braided cable in fixed position within the retaining ring; (e) clamping the braided cable and the retaining ring as a unit in an anode fixture so that the wrapped end portion of the braided cable faces the ignition projection of the electrically cond

Abstract: A push rod is manufactured by projection-welding a bottom surface of an end element to a tapered annular end surface of a pipe. To prevent some inclination from arising between the bottom surface of the end element and the annular end surface of the pipe when they are tightly pressed against each other, the bottom surface is formed integrally with a plurality of rose seats of wedge shape in cross section that extend radially with respect to the axial center of the end element. Projection-welding is performed after the rose seats are brought into confronting contact with the tapered annular end surface of substantially triangular shape in cross section.

Abstract: The quality of a percussion weld is sensed by measuring and analyzing certain features of the weld current signature. Instantaneous current is measured by a Hall sensor and permits isolation of the welder from the monitoring system. Weld quality is strongly correlated to the time to vaporize the nib separating the parts, and the dwell time to forge the parts together after nib explosion. A weld is assumed defective if nib time is too short or dwell time is too long. These quality parameters may be supplemented by weld and forge timing, line voltage, and acoustic information; a weld is rejected if any of these are outside of acceptance limits. Experiments on the percussion welding of silver-cadmium oxide to brass show that cadmium-oxide is decomposed and expelled by the forge pressure and the joint is a silver to brass weld.

Abstract: Two metal plates 1a, 1b are projection welded together using a truncated conical projection 12 on a first one of the plates having a spherical end surface. The plates are pressed together through the projection, and a welding current pulse is applied which reaches a maximum value in less than 2 milli-seconds. The shape and dimensional limitations of the projection coupled with the high amplitude, short duration current spike result in a thin welding nugget 9 and prevent any thermal distortion of the outer plate surface due to localized overheating.

Abstract: A method for joining individual pieces of material together includes the steps of heating the pieces to be welded together, at least one of which consists of a metal matrix with a relatively low melting point and a reinforcement material distributed therein, the reinforcement having a relatively high melting point. The other piece may be a similar metal matrix composite, or may be a metal or alloy which is to be joined to the first piece. The pieces are heated to a temperature which is above the melting points of the metals and below the melting point of the reinforcement. The pieces so heated are brought into contact with one another and then cooled to a temperature below the melting points of the metals. One technique for practicing the method of the invention is that of capacitor discharge welding.

Abstract: A method and apparatus for improved percussive arc welding is disclosed. In this technique a test arc of a voltage no greater than the initiating voltage of the percussive arc welding is first applied across the pieces to be welded. The welding cycle is then performed if, and only if, an arc is detected responsive to the impressing of the test voltage.

Abstract: Submerged percussion welding is disclosed wherein the parts to be welded are in intimate contact with a liquid, such as water, during explosion and vaporization of the arc starter therebetween. In preferred form, one part is mounted to a stationary bottom electrode around which a movable water tank is raised to immerse the part. The other part, mounted to a movable top electrode, is brought into contact with the first part and the weld is completed under water.

Abstract: A welding method and means is disclosed utilizing a conductive foil disposed between or adjacent members to be welded together with the foil serving as one electrode and one or both of the members serving as another electrode of the welding circuit and with the members being forced together or with the foil being forced against the members by a separate electrode.