tailieunhanh - Extrusion Subjects of interest

This chapter aims to provide useful information on different extrusions processes, which can be mainly divided into direct and indirect extrusion processes. This also includes basic background on hydrostatic extrusion, extrusions of tubing and production of seamless pipe and tubing. • Principal background and concept of extrusion will be addressed along with the utilisation of mathematical approaches to understand the calculation of extrusion load. | Chapter 4 Extrusion Subjects of interest Introduction objectives Classification of extrusion processes Extrusion equipment Presses dies and tools Hot extrusion Deformation lubrication and defects in extrusion Analysis of the extrusion process Cold extrusion and cold-forming Hydrostatic extrusion Extrusion of tubing Production of seamless pipe and tubing Suranaree University of Technology Tapany Udomphol Jan-Mar 2007 Objective This chapter aims to provide useful information on different extrusions processes which can be mainly divided into direct and indirect extrusion processes. This also includes basic background on hydrostatic extrusion extrusions of tubing and production of seamless pipe and tubing. Principal background and concept of extrusion will be addressed along with the utilisation of mathematical approaches to understand the calculation of extrusion load. The role of lubricants on the deformation process which results in the improvement in extrusion products will be provided. Finally defects and its solutions occurring in the extrusion process will be emphasised. Suranaree University of Technology Tapany Udomphol Jan-Mar 2007 What is extrusion Extrusion is the process by which a block billet of metal is reduced in cross section by forcing it to flow through a die orifice under high pressure. In general extrusion is used to produce cylindrical bars or hollow tubes or for the starting stock for drawn rod cold extrusion or forged products. Most metals are hot extruded due to large amount of forces required in extrusion. Complex shape can be extruded from the more readily extrudable metals such as aluminium. The products obtained are also called extrusion Suranaree University of Technology Tapany Udomphol Jan-Mar .