Simulation of Gas and Spray Quenching during Extrusion of Aluminium Alloys

Abstract

After the extrusion process most aluminium alloy profiles don´t satisfy the necessary strength requirements. An increase of strength can be obtained by age hardening of hardenable aluminium alloys. Age hardening includes the three steps of solution annealing, quenching and aging and is usually carried out in a separate process after extrusion. The integration of the sub-steps solution annealing and quenching in the extrusion process results in a marked reduction of the complete process chain. The applicability of this integration depends primarily on the quenching power of the cooling module and on the quench sensitivity of the aluminium alloy. Using the finite element method the non-steady-state process of quenching the profiles after leaving the extrusion press has been simulated. The boundary conditions for quenching are varied for a gas nozzle field and a spray cooling using heat transfer coefficients based on experiments. The simulation results support the design of gas nozzle fields or spray cooling for the extrusion process of different aluminium alloys.

Mechanical properties of undercooled aluminium alloys and their implementation in quenching simulation

“…Therefore, thermophysical properties, precipitation behaviour and mechanical properties of the simulated alloys are required, depending on the temperature and microstructure. 1,2 In the case of quenched aluminium alloys, this means properties of undercooled states. The mechanical properties of these non-equilibrium microstructures are not available.…”

“…To predict microstructures and properties as well as residual stresses and distortion, heat treatment simulation by the finite element method is a very powerful tool. Therefore, thermophysical properties, precipitation behaviour and mechanical properties of the simulated alloys are required, depending on the temperature and microstructure 1,2. In the case of quenched aluminium alloys, this means properties of undercooled states.…”

A Phenomenological Mechanical Material Model for Precipitation Hardening Aluminium Alloys

“…Thus, the precipitation state, and therefore, the mechanical properties, change during short-term heat treatment. In heat treatment simulation, modelling the quenching of steels [1][2][3][4] and aluminium alloys [5][6][7][8] has been the subject of intensive research and is now used in many industrial applications [9]. In addition, numerical descriptions of the heat treatment processes are also used to simulate various manufacturing processes such as welding steels [10], aluminium alloys [11] or induction hardening [12].…”

“…For aluminium alloys, some material models have also been developed. However, these are designed for special areas such as quench simulation [5][6][7] or ageing simulation [17,18]. However, these quench simulation material models can provide only temperature-dependent flow curves, while the ageing models only describe the change in mechanical properties during ageing.…”

Sintering and Heat Treatment of Titanium Alloys by Pulsed Electric Current Sintering

“…Due to poor thermal transfer characteristics (lower cooling rate) of gases under normal conditions, they have to be optimized by proper adjustment of gas pressure and flow speed. In principle, gas quenching can be performed in two ways [5][6][7][8], namely: at low or atmosphere pressure with high gas velocity or at high pressure with limited gas velocities. The first part of this chapter will focus on new modifications of the PECS technique.…”