Papers by Keyword: Cold Plastic Deformation

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Authors: Gina Sicoe, Doina Iacomi, Monica Iordache, Eduard Niţu
Abstract: Abstract. Processing profiles through form tapping process with planetary rollers is used in industry, especially in the automotive industry. Even though this process exists for several decades, few studies dealing with this topic were published. The main objective of this paper was to determine the influence of the two process parameters on three important values which influence the quality of profiles: the rolling force, the state of stresses in the deformed material and on the rolling time. The material used was carbon steel AISI 1015.
Authors: Monica Iordache, Eduard Niţu, Doina Iacomi
Abstract: Numerical Simulationis a Modern Method to Optimize Cold Plastic Deformation Processes in Order Toprovide Product Quality, Reduction of Time and Costs of Execution. One of Theimportant Problems of Numerical Simulation is the Mode of Characterizing Theplastic Behaviour of the Material which Undergoes Deformation. the Resultsobtained through Simulation are Closer to Real Ones as the Description Ofmaterial Behaviour of the Piece is Done as Accurately as Possible. Thesimulation Results Depend on the Stress-Strain Relationship which is Obtainedexperimentally by Compression Tests. the Paper Presents the Mode of Determiningthe Constitutive Equation Starting from the Results of the Compression Test.This Test was Used because it Allows Achieving High Strain and the Stressdistribution is Similar to other Corresponding Plastic Deformation Processes.
Authors: Bin Xu, Le Yang, Shi Bo Xing, Li Li
Abstract: In order to increase boronizing speed without decreasing the hardness of boride layer, the effect of plastic deformation at room temperature on powder RE-chrome-boronizing for a medium carbon steel (steel 45), in which boronizing plays a main role, was studied in this paper. The cold plastic deformation (CPD), whether compressing or shot-peening, can increase boronizing speed. Meanwhile, the boride layer can also retain its high microhardness (1 300―1 900HV0.1) with low brittleness. The layer depth achieved for a given heating time increases with increasing CPD degree on the steel. The analyses show that boronizing kinetics in the RE-chrome-boronizing (RE-Cr-B) samples with CPD can be enhanced.
Authors: Doina Iacomi, Monica Iordache, Eduard Niţu, Stefan Tabacu
Abstract: Processing through volumetric cold plastic deformation (cold rolling) with flat wedge tools is a procedure used in mass production to process profiles (circular, threads, grooves, teeth) on revolution pieces. Complex profiles obtained by cold plastic deformation with flat wedge tools have important advantages: material economy, high productivity, continuous fibre, superior mechanic properties, low values of the roughness parameters, low costs. In recent years, the simulation of processes of volumetric plastic deformation by the finite element method is used to obtain the optimization of the deformation process and the improvement of the product quality even from the design stage. By numerical simulation there is observed the evolution during the process of different parameters such as: stress and deformations in the deformed body, mode of material flow, final shape and sizes of the product etc. Therefore, it becomes possible to analyse the process even from the design stage by identifying the problems which can appear and their influence on some characteristics of the product obtained: geometry, state of deformations and stress.This paper presents the experimental determination of the deformation force at the processing of complex profiles with flat wedge tools and the influence of the friction coefficient between tool and semi-product on its value; influence established by simulating the deformation process. The process also has been simulated by means of finite element calculations using the Abaqus/Explicit code. The material behaviour is described by using a 5-parameter strain-hardening law and by accounting for thermal effects at high strain-rates. The comparison between the values and the variation of the deformation force recorded experimentally and at simulation allows establishing the optimal value of the friction coefficient and validating the numerical model developed.
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