Consideration on Stainless Steel Plate Plastic Deformed by Fluid Impact Substances and Pressured Nitrogen Blasting ADRIAN ROSCA 1 , DANIELA ROSCA 1 , VASILE NASTASESCU 2 1. University of Craiova 13, A. I. Cuza Street, 200585, Craiova 2. Ministry for Education and Research ROMANIA adrosca2003@yahoo.com , http://www.ucv.ro , vasile.nastasescu@mec.edu.ro Abstract: The paper presents a plastic deformation method for thin plates made of stainless steel, plastic deformed by pressured nitrogen blasting combined with impact fluid substances. There are presented experimental results for comparative values of deformation velocities obtained by different initial pressured nitrogen blasting, respectively by pressured nitrogen blasting combined with several quantities of impact fluid substances. Key-Words: - Pressured nitrogen blasting, Plastic deformation, Stainless steel thin plates 1. Introduction In the present stage of technological development, a new method of metal plate plastic deformation process by shock waves gazes blasting, combined with impact substances (pulverulent / fluid), comes to complete, but not to replace, the diversity of high velocity deformation procedures: explosive substances, exploding wires in gasses, electro- hydraulic or magneto-hydraulic impulses, Dynapac hammer [1, 2, 3]. Designed for the first time in a Romanian R&D Institute, this new method was developed to produce parts for medium and low voltage special electric motors. Several types of tight lid for bearings made from Carbon Steel plates were obtained. Due to the elastic proprieties of the circular edge of the part obtained using this deformation method, this tight lid is used in the same time as safety Seger ring for the bearings. In the last years, this new plastic deformation method was improved to obtain spherical segment shaped plates made from porous materials, specially designed to protect the molecular sieves in the air filtration and drying modules (components of pressure swing adsorption oxygen generator systems) [5,6,7,9]. In principle, the new plastic deformation process using pressured gazes blasting and impact substances, is based on the physical phenomenon of compressed gas discharged from a pressured vessel. A special convergent-divergent nozzle was designed to obtain 350÷720m/s discharge velocity. The pressured gaze’s shock wave combines the impact substances (pulverulent / fluid), which are accelerated to the circular plate embedded in the contour of an open die. A plastically deformed part is obtained with no punch die action [5,7, 9]. In order to estimate the performance of this new plastic deformation process, an experimental research method was designed for simultaneous determination of the maximum transverse deformation, and of the deformation velocity of the thin plate deformed by gazes blasting shocks combined with different quantities of impact substances (quartz; water). 2. Theoretical considerations concerning the blasting shock wave velocity Technical equipment functioning, usually called air cannon /air blaster, is based on the expanding effect of the compressed gas wave shock discharged with high velocity from a storage vessel. During this fast process, the gas flow is characterized by high rate pressure variation; therefore there is no heat exchange with the outside environment, and the flow process can be considered adiabatic.[5,7] For adiabatic process, from the Bernoulli equation for compressible fluids, it results: o o 2 0 2 p 1 k k 2 v p 1 k k 2 v ρ ρ ⋅ − + = ⋅ − + , (1) where p o and ρ o are the initial parameter of the gas; p and ρ are the final parameter of the gas; k is the adiabatic coefficient; v o is the initial gas velocity (in the storage vessel v o = 0) . WSEAS TRANSACTIONS on APPLIED and THEORETICAL MECHANICS Adrian Rosca, Daniel Rosca and Vasile Nastasescu ISSN: 1991-8747 1 Issue 1, Volume 3, January 2008