TY - JOUR

T1 - Numerical and experimental investigations of the anisotropic transformation strains during martensitic transformation in a low alloy Cr-Mo steel 42CrMo4

AU - Behrens, Bernd Arno

AU - Bouguecha, Anas

AU - Bonk, Christian

AU - Chugreev, Alexander

N1 - Funding information: The authors wish to express sincere thanks to the German Research Foundation (DFG) for financial support of the research project BE1691/142-1 Siulatiom“n of te h undesired distortions in hot forged and subsequently heat trpeatedeocontsconnidme seriingacmt fnteadsutressytate sstnotrhrfsatiopnmicitlast”.y

PY - 2017/11/15

Y1 - 2017/11/15

N2 - Hot forming as a coupled thermo-mechanical process comprises of numerous material phenomena with a corresponding impact on the material behavior during and after the forming process. Within the subsequent heat treatment, possible rapid cooling of the hot formed parts leads to the diffusionless decomposition of austenite into martensite. In this context, in addition to the elastic, plastic and linear thermal strain components, complex isotropic as well as anisotropic transformation strains can occur. Irreversible anisotropic transformation strains account for the plastic deformation at the phase boundary between the emerging and the parent phase and are related to the transformation induced plasticity (TRIP or TP) phenomena. Moreover, TRIP strains can be reduced or amplified by varying the current stress state. These phenomena significantly contribute to the final residual stress state and may be responsible for the cost-intensive component defects arising due to thermal shrinkage. This study aims at developing an FE-based material model in order to describe and quantitatively visualize stress dependence of the transformation induced anisotropic strains for a typical forging steel 42CrMo4. The developed material model as well as the aspects of its implementation in a commercial FE-system (Simufact.forming) is presented. Consequently, the discussed material model is tested by comparison of experimental and numerical results with respect to resulting dilatation under various stress states.

AB - Hot forming as a coupled thermo-mechanical process comprises of numerous material phenomena with a corresponding impact on the material behavior during and after the forming process. Within the subsequent heat treatment, possible rapid cooling of the hot formed parts leads to the diffusionless decomposition of austenite into martensite. In this context, in addition to the elastic, plastic and linear thermal strain components, complex isotropic as well as anisotropic transformation strains can occur. Irreversible anisotropic transformation strains account for the plastic deformation at the phase boundary between the emerging and the parent phase and are related to the transformation induced plasticity (TRIP or TP) phenomena. Moreover, TRIP strains can be reduced or amplified by varying the current stress state. These phenomena significantly contribute to the final residual stress state and may be responsible for the cost-intensive component defects arising due to thermal shrinkage. This study aims at developing an FE-based material model in order to describe and quantitatively visualize stress dependence of the transformation induced anisotropic strains for a typical forging steel 42CrMo4. The developed material model as well as the aspects of its implementation in a commercial FE-system (Simufact.forming) is presented. Consequently, the discussed material model is tested by comparison of experimental and numerical results with respect to resulting dilatation under various stress states.

KW - 42CrMo4

KW - finite element analysis

KW - multiscale material modelling

KW - transformation induced plasticity

UR - http://www.scopus.com/inward/record.url?scp=85036626684&partnerID=8YFLogxK

U2 - 10.1016/j.proeng.2017.10.944

DO - 10.1016/j.proeng.2017.10.944

M3 - Conference article

AN - SCOPUS:85036626684

VL - 207

SP - 1815

EP - 1820

JO - Procedia Engineering

JF - Procedia Engineering

SN - 1877-7058

T2 - International Conference on the Technology of Plasticity, ICTP 2017

Y2 - 17 September 2017 through 22 September 2017

ER -