3 Fundamentals of press design

6 Solid forming (Forging)
6.2 Benefits of solid forming
6.2.1 Economic aspects
The benefits offered by solid forming, compared with other production
processes, can be summarized as superior quality combined with lower
manufacturing costs. The standard of quality is due to the favorable
mechanical properties of cold and warm forged parts, such as high strength
and toughness, an uninterrupted fiber flow, close tolerances and a good surface
quality. The cost benefit achieved using forging techniques can be considerable,
but does depend on the specific part considered and on the previously
used production method. Individual cost factors include:
– Low material input: Almost the complete initial volume of the billet is
processed into the finished part. Compared to machining, savings
can be as great as 75% (Fig. 6.2.1). Where high-alloyed materials are
used, the benefit of low material input becomes increasingly significant
in relation to overall manufacturing costs.
– Use of low-cost raw materials:Strain hardening that occurs during warm
and cold forming results on the one hand in higher levels of flow
stress, but also in higher ultimate and fatigue strength. Therefore, it is
possible to use lower-cost steel grades with lower initial strength characteristics
in order to achieve the same mechanical properties obtainable
in machined parts. A workpiece with, for example, a hexagonal
geometry is produced where machining methods are used from costly
extruded material with a hexagonal cross section. By forging instead of
machining, this type of part can be formed using substantially less
expensive round bar as starting material.
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998