Author/Authors :
Mirzakhani, B. iran university of science and technology - School of metallurgy and Materials Engineering - Center of Exellence Advanced Materials and proccessing, تهران, ايران , Arabi, H. iran university of science and technology - School of Metallurgy and MaterialsEngineering - Center of Excellence of Advanced Materials and Processing (CEAMP), تهران, ايران , Salehi, M. T. iran university of science and technology - School of Metallurgy and Materials Engineering - Department of Metallurgy and Materials Engineering, تهران, ايران , Seyedein, S. H. iran university of science and technology - School of Metallurgy and Materials Engineering, تهران, ايران , Aboutalebi, M. R. iran university of science and technology - School of metallurgy and Materials Engineering - Center of Exellence Advanced Materials and proccessing, تهران, ايران , Khoddam, Sh. Monash University - Mechanical Engineering Department, Australia , Mohammadi, A. Advanced Materials Research Institute, ايران
Abstract :
Abstract:Optimization of specimen geometry before subjecting it to hot torsion test (HTT) is essential for minimizingnon-uniform temperature distribution and obtaining uniform microstructure thought the specimen.In the present study, a nonlinear transient analysis was performed for a number of different geometries andtemperatures using the commercial finite element (FE) package ANSYSTM. FE thermal results then were applied tooptimize HTTspecimen produced from API-X 70 microalloyed steel taking into account the microstructurehomogeneity. The thermodynamic software Thermo-calcTM was also used to analysis solubility of microalloyingelements and their precipitates that may exist at different equilibrium conditions. In addition the behavior of austenitegrain size during reheating was investigated. The results show high temperature gradient occurred in long specimens.This could lead to non homogeneous initial austenite grain size and alloying element or precipitates within the gaugesection of the specimen. The proposed optimization procedure can in general be used for other materials and reheatingscenarios to reduce temperature. This then creates more homogeneous initial microstructure prior to deformation andreduces errors in post processing of the HTTresults
Keywords :
Hot torsion test , temperature gradient , Geometry optimization , Simulation , Microalloyed steel
