In this work, the distortion failure of mechanical components undergoing a heat treatment is dealt with. Samples made of a 9–12% Cr steel with beam-like geometry and different set-ups in the furnace were measured with laser scanner system, before and after a solubilization (air quenching) heat treatment to evaluate its permanent deflection. A numerical model, based on the Finite Element (FE) method, was then developed and a transient thermo-mechanical analysis was performed to simulate the thermal cycle. A simulation approach, which differs from the usual methodology adopted dealing with quenching, is proposed, taking into account phase changes (Sang's semi-empirical method) but also viscoplasticity (Nabarro-Herring creep law combined with bilinear elasto-plastic kinematic model), while the material properties were related to temperature. Comparing numerical results with experiments, it has been observed that, with respect to the case of water quenching, where the distortion is mainly related to phase transformation strains and TRIP (Transformation Induced Plasticity), in the considered case the failure seems to be mainly affected by a low-stress diffusional creep due to the proper weight, when the component is held at high temperature. The influence of different set-up to support the sample in the furnace was also investigated.

Distortion after solubilization treatment of X12CrNiMoV12-3 beam-like samples: A novel FE modelling technique supported by experiments

De Bona F.;Srnec Novak J.;Lanzutti A.;
2022

Abstract

In this work, the distortion failure of mechanical components undergoing a heat treatment is dealt with. Samples made of a 9–12% Cr steel with beam-like geometry and different set-ups in the furnace were measured with laser scanner system, before and after a solubilization (air quenching) heat treatment to evaluate its permanent deflection. A numerical model, based on the Finite Element (FE) method, was then developed and a transient thermo-mechanical analysis was performed to simulate the thermal cycle. A simulation approach, which differs from the usual methodology adopted dealing with quenching, is proposed, taking into account phase changes (Sang's semi-empirical method) but also viscoplasticity (Nabarro-Herring creep law combined with bilinear elasto-plastic kinematic model), while the material properties were related to temperature. Comparing numerical results with experiments, it has been observed that, with respect to the case of water quenching, where the distortion is mainly related to phase transformation strains and TRIP (Transformation Induced Plasticity), in the considered case the failure seems to be mainly affected by a low-stress diffusional creep due to the proper weight, when the component is held at high temperature. The influence of different set-up to support the sample in the furnace was also investigated.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11390/1221303
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