PRESS VS HAMMER FORGING

 The choice between these two methods is mainly determined by the shape , size and weight of  the forging to be made. Hammer-forging depends upon a large number of blows applied in rapid succession. This hammer-blow produces shock and vibration to the structure , its foundations, and surroundings which impose a practical limit to the size of  a hammer. The hammering process tends to give more thorough effect than the pressing which is more in the nature of kneading. Where the thickness of metal is large the effects of hammering may not penetrate right through, and the outer surface of  the metal will be better worked than those deeper below. Another important factor is the speed of  operation which can be altered according to the size of the forging. In hammering, its position must be altered rapidly between the blows and this can be done up to a limited size and weight.

Press action is slow in comparison to hammer action, but the reduction in the size of heavy parts is comparatively rapid. Press forging provides a method for forming various sized shapes that would not be practicable under a dynamic type of load. Size is not a definite restriction in this process, and therefore, the product lends itself quite readily to almost any shape. An important effect of press forging is the dispersion of the non-metallic inclusions throughout the metal, which tends to minimize their effects. As a general rule, hammers are employed up to about 10 tons capacity, but hydraulic presses, in general use , range about 20,000 to 15,00,000 kg . Press forging which provides a uniform finished shape is versatile method of forming metals. It may be competitive with drop forging but can often can be used where drop forging is not feasible. Shapes formed by press forging are generally dense and homogeneous in structure.