Tutorial: Engineering technology Topic: Volume forming Prepared by: Ing. Elena Nová Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.
Division of forging processes in accordance to external forces: From this view forging is divided on: 1. Volume forging, deformation is in the direction of all three axes and consists of: rolling; forging (free and swage), extrusion and rod / wire drawing. Volume remains constant. Strengthening results -> drop in ductility -> restriction in used of forging operations
2. Rolling, here is a deformation in two directions. Here belongs drawing, bending, cutting etc. Required product shape (mostly from flats) is achieved without basic change in thickness or diameters of entry material Mechanical properties remains unchanged
Rolling – is plasticization (permanent shape change) of metal between two turning rolls which are continually depressed. Rolled material is elongated and compressed. Principle of longitudinal (left), transversal (middle) and oblique rolling (1,2 – rolls, 3 – material)
At longitudinal rolling material is forged in longitudinal direction. Most from steel and other metals is produced in this manner. Rolling is provided mostly using high (hot temperatures but also as cold rolling. Rolling firstly produce semi-finished products. From them are rolled final sections. Similarly are produced rods, rails, strips and sheets – those are long products.
At oblique rolling – is rolling with extra-axial rolls – example is tube rolling. Two types of seamless tubes manufacturing:
Transversal rolling, reduce radial cross section and is used for example on stepped shafts. Rolls of rolling mills are either smooth or calibrated.