Forgings are formed under the action of external forces, therefore, the correct calculation of deformation force, is the basis for the selection of equipment, mold check.Stress and strain analysis on the interior of the deformed body is also indispensable for optimizing the process and controlling the microstructure and properties of the forging.

There are four main analysis methods of deformation force.Although the principal stress method is not very rigorous, it is simple and intuitive, and can be used to calculate the total pressure and the stress distribution on the contact surface between the forging and the tool.The slip line method is strict for the plane strain problem and intuitive for solving the stress distribution of the local deformation of the high piece, but its application scope is narrow.The upper bound method can give the overestimated load and the upper bound element can also predict the shape change of the forging during deformation.Finite element method can not only give the external load and the shape change of the forging, but also give the internal stress and strain distribution.There has been a recent trend to adopt a joint approach to problem analysis, for example.The upper limit method is used for rough calculation, and the finite element method is used for fine calculation in key parts.