Projeto de matriz de extrusão para processo de deformação severa – Equal Channel Angular Pressing (ECAP)

Abstract

Of the approaches used to improve the mechanical properties of light metals, Equal Channel Angular Pressing (ECAP) is one of the most promising. When a specimen is forced through a channel with a large change of direction, the grains are refined in micrometric scales. One of the advantages of using this method is its ease of implementation, requiring little equipment. Of the different designs for the construction of dies for severe deformation by ECAP, the design of interchangeable inserts is the most versatile, allowing different tests to be carried out when changing the extrusion angle while maintaining most of the structure of the die. The project started with the evaluation of the influence of the multiple factors that influence the ECAP process, using the theory of mechanical failures to dimension the matrix components. It was decided to design a channel with an extrusion angle of 90 °, which should promote an average deformation equivalent to 0.94 per pass. The interchangeable inserts, the punch and the sides must be built in STEEL 4340, the screws, nuts and washers must be of class 10.9 with 10 mm in diameter. The base can be constructed of 1020 steel as it does not suffer as much effort. The maximum load not to be exceeded was calculated based on the lowest safety coefficient of the set, which occurs at the punch, and is 136476 N. The minimum preload applicable to the screws must be 22858.2 N and must be applied with the use of a torque wrench. It is possible to use other extrusion angles as long as they are greater than 90 ° and will result in less equivalent deformation per pass.