Category: Mechanical Working Of Metals, Sheet Metal Work, And Powder Metallurgy

Just as in electrohydraulic forming, the electrical energy is first stored in a capacitor bank. This energy is then discharged through a coil by closing the switch. The coil produces a magnetic field, the intensity of this field depends on the value of the current. Since the metallic workpiece is in this magnetic field, a…

Electric discharge in the form of sparks in the place of explosives can also be used to generate a shock wave in a fluid. An operation using the principle of generating a shock wave is called electrohydraulic forming. The characteristics of this process are very similar to those of explosive forming. The capacitor bank is…

In the explosive forming (Figure 21.10), shock wave is generated in a fluid medium by detonating an explosive charge. The entire wavefront is utilized in a confined space. But, for large object the wavefront may be used for unconfined space and it is less effective than confined space. The typical explosives include TNT and dynamite…

If the rate of energy flow for forming is high, it is known as high energy rate forming. Energy used may be chemical, magnetic, electro discharge, etc. High energy rate forming operation is performed in very less time. Explosive forming, electrohydraulic forming, and electromagnetic forming are the examples of high energy rate forming.

Like bar drawing, tube drawing is accomplished in most cases with the use of draw bench. Fixed mandrel (Figure 21.9a) is most commonly used to control the tube’s internal diameter; Figure 21.9b uses floating mandrel which adjust itself to the correct position because of its stepped contour; cylindrical mandrel (Figure 21.9c) is usually used for small-sized tubing,…

An important difference between the bar drawing and wire drawing is that the bars must remain straight. The length of the bar which can be drawn is limited by the maximum travel of the carriage, which may be from 50 to 100 ft. The first operation, preliminary to drawing is the pointing of the bars…

Wire drawing is a process to produce a small diameter wire from billet by applying tensile force. A leading end of a wire to be drawn is pointed in a rotary swaging machine or by some other means. The point is then inserted through the die then properly gripped and pulled sufficiently by a suitable…

It is essentially a cold process which is mostly used for making collapsible medicine tubes, tooth paste tubes, shaving cream tubes, and food canes from more ductile metals such as zinc, lead, tin, aluminium, copper, etc. During the process, the billet is placed in a die cavity and is given a strong single blow through…

Cold extrusion is carried out at room temperature. Because of the large forces required in extrusion, most metals are extruded hot where the deformation resistance of metal is low. At the same time strain hardening is also eliminated in hot extrusion.