Improvement of the Design of Rocket Propelled Granite (RPG.7) Main Tubes Forging Dies

Abstract

This paper presents a proposed new design of a forging die used for producing the forged tube of a rocket launcher. In the practiced technology for producing as the forged tube many problems raised as a result of the selection of the parting line (P.L.) at the upper tangent of the circular cross-section of the product, which resulted in a semi-parabolic cross- section that causes some technical mishaps which can be summarized in the following points: the large amount of raw material lost as turning chips during the turning process of the machined tube; The high consumption rate of tools during the turning process of the machined tube; damage caused by rough turning lathe machine as a result of the high vibrations due to turning of a non-cylindrical profiles and the short life-time of the forging die due to its embracing of the majority of the volume of the forge tube. In the proposed design the parting line (P.L.) will be located in the mid-section of the circular cross-section of the product (the forged tube) in order to solve these problems .This led to a design of a new set of hammering dies and subsequently a set of trimming dies by applying the standard design considerations and with the help of the CAD/CAM package software: ”VISI-15”. The proposed design differs significantly from the upsetting forging which have a parting line perpendicular to the longitudinal rolling direction of the forged product. When using the new designed dies, the saving in an input raw material (weapon steel) is estimated to reach up to 5 kilograms per forged tube. This became a considerable saving in the annual production cost. Minimizing the handling weight of the forged tube (from 16 Kg/Piece to 5 Kg/Piece) during the production processes results in a relatively less man power effort compared with the practiced technology. Besides the minimization of the consumption rate of the cutting tools and the rate of the replacement of the rough turning machines