The stochastic nature of typical cold forging processes is assessed in this paper. Finite element computations have been applied to backward can extrusion, free upsetting, closed-die forging and forward rod extrusion in order to study the influence of scatter of the principal process input parameters on the dimensional accuracy of products and on the tool service life. The results show that stochastic interactions differ radically for the four typical cold forging processes and that press stiffness has a significant influence on the stochastic relationships.
COBISS.SI-ID: 1007711
Due to rapid development in automotive, aircraft and power industries, the use of light alloys and their development has extensively increased. In order to reach this demand new innovative design concepts has been introduced resulting in development of bulk functionally graded materials. The purpose of the present study was to examine the oxidation of Mg–Al alloys in the atmosphere of oxygen at various temperatures. The results show that the oxide layer can either protect the material against progressive oxidation or it can cause complete disintegration of material.
COBISS.SI-ID: 909151
In this paper the Latin hypercube sampling technique (LHS) was used for modelling of the uncertainty of industrial data and CAE NN was used for analysis of the mutual dependence of influencing parameters. Using the example of AISI D2 tool steel, the proposed method was applied for determination of relationships between chemical composition and yield by considering the corresponding coefficients of variation. New insights of relationships were directly applicable in the industrial practice.
COBISS.SI-ID: 894815
Laboratory compression tests at different temperatures and strain rates have been performed on Nimonic 80A superalloy to define optimal hot forming characteristics. A mathematical expression connecting mean grain size and true stress is presented using a Hall-Petch-like equation. The evolution of microstructure at various sample positions in correlation with deformation temperatures, strain, and strain rates has also been investigated. Optimal hot-working conditions are determined using processing maps and obtained microstucture.
COBISS.SI-ID: 897375
A non-parametric model was proposed for modelling the influence of different technological and chemical parameters on the mechanical properties of the 6082 aluminium alloys during the hot extrusion process with a special consideration of human factor. It was shown that human factor was important and that it could be efficiently modeled and taken into account by the proposed Conditional Average Estimator (CAE) method. It was found that the highest values for elongation and yield stress did not coincide with the range of the most frequent combinations of input parameters.
COBISS.SI-ID: 980319