Forging streamline interpretation

The forging streamline is also called flow pattern. In the forging, the brittle impurities of the metal are broken and distributed in a granular or chain shape along the main elongation direction of the metal; the plastic impurities are distributed along the main elongation direction along the metal deformation. Thus, the metal structure after hot forging has a certain directionality.

The forging flow line makes the metal properties anisotropic; the tensile strength along the flow line direction (longitudinal direction) is higher, and the tensile strength perpendicular to the flow line direction (lateral direction) is lower. If the longitudinal strength of the streamline is high in the production, the streamline structure in the forging is continuously distributed and consistent with the direction of the tensile force, which will significantly improve the bearing capacity of the part. For example, when the hook is formed by a bending process, the direction of the flow line can be aligned with the direction of the force of the hook (Fig. a), thereby improving the ability of the hook to withstand the tensile load. In the forged and formed crankshaft shown in Fig. b, the distribution of the flow lines is reasonable. Figure c is a crankshaft that has been cut and formed. The flow line is unreasonable due to discontinuous flow lines.