Category: Mechanical Sheet Metal Work, Powder Metallurgy, Metals

This is variation of impression die forging without flash (Figure 21.5b). It has better utilization of material than open flat dies, better physical properties, closer dimensional, tolerance, high production rate, etc. In impression die forging the heated workpiece is placed between two required shaped die and is pressed or hammered. During hammering or pressuring it…

In open die forging, the hot workpiece is placed between two flat dies and is hammered to produce the desired shape. There is no flow of metal in this process. This is a slow process and may be performed by presses in addition to hammer (Figure 21.5a). It is repeatedly manipulated between the dies until…

Forging is a process of plastic deformation for shaping. The force applied in this case is intermittently compressive force while in a rolling process force applied is continuous compressive force.

There are two types of rolling defects—surface defects and internal defects as shown in Figures 21.3 and 21.4, respectively. Figure 21.3 Surface Rolling Defects Figure 21.4 Internal Rolling Defects

The different types of rolling mills are shown in Figure 21.2. In two high rolls mill (pullover), the stock is returned to the entrance for further reduction. In two-high mill (reversing), the work can be passed back and forth through the rolls by reversing their direction of rotation. In three high rolls mill, upper and lower…

Rolling is the process of reducing the thickness or changing the cross-sectional area of the workpiece by means of rolling mills. It is performed through hot working or cold working. The metal is drawn into the opening between the rolls by frictional forces between the metal and roll surface as shown in Figure 21.1. The metal…

Mechanical working is a process of shaping of metals by plastic deformation. When a metal is subjected to external force beyond yield strength but less than fracture strength of the metal, metal is deformed by slip or twin formation. There are two types of mechanical working process: cold working and hot working. When metal is…