TY - JOUR

T1 - Effect of Different Intercritical Annealing Treatments without and with Overaging on the Mechanical Material Behavior

AU - Wolf, Lars Oliver

AU - Cordebois, Jean Pierre

AU - Rodman, Dmytro

AU - Nürnberger, Florian

AU - Maier, Hans Jürgen

N1 - Funding information: The authors thank the German Research Foundation (DFG) for financial support of the project “Process Adapted Dual Phase Steels” within the framework of the International Research and Training Group (IRTG) 1627.

PY - 2018/7/31

Y1 - 2018/7/31

N2 - In the last decade, press-hardening of manganese-boron steels for the manufacturing of safety-relevant components has become a well-established industrial process. Thereby, very high strengths are achieved with pure martensitic microstructures. However, in certain areas of the car body structure more ductile components are necessary to absorb crash energy. For tailoring the material properties, two- or multiphase microstructures can be induced by rolling and heat treatment processes. The press-hardening steel 22MnB5 which is employed in the present study, is used to manufacture three different ferritic-martensitic microstructures. These different materials are characterized by classical mechanical models, based on experimental results. For the mechanical description of the initial yield stress depending on the stress state of different multiphase steels, the Hill model is calibrated. The elastic limit and the kinematic hardening of three various heat treatment conditions are determined using conventional tensile tests and the Galimel test, respectively. Therefore, the applied mathematical relations are derived and adapted for the performed investigations. The relationship between the load conditions and the proper application of the equations are explained. The resulting microstructures are characterized and the ramifications with respect to their energy absorption capability are discussed.

AB - In the last decade, press-hardening of manganese-boron steels for the manufacturing of safety-relevant components has become a well-established industrial process. Thereby, very high strengths are achieved with pure martensitic microstructures. However, in certain areas of the car body structure more ductile components are necessary to absorb crash energy. For tailoring the material properties, two- or multiphase microstructures can be induced by rolling and heat treatment processes. The press-hardening steel 22MnB5 which is employed in the present study, is used to manufacture three different ferritic-martensitic microstructures. These different materials are characterized by classical mechanical models, based on experimental results. For the mechanical description of the initial yield stress depending on the stress state of different multiphase steels, the Hill model is calibrated. The elastic limit and the kinematic hardening of three various heat treatment conditions are determined using conventional tensile tests and the Galimel test, respectively. Therefore, the applied mathematical relations are derived and adapted for the performed investigations. The relationship between the load conditions and the proper application of the equations are explained. The resulting microstructures are characterized and the ramifications with respect to their energy absorption capability are discussed.

KW - heat treatment

KW - low-alloyed steel (22MnB5)

KW - mechanical characterization

KW - microscopy

KW - optical metallography

KW - partial martensitic steel

UR - http://www.scopus.com/inward/record.url?scp=85054197987&partnerID=8YFLogxK

U2 - 10.1002/srin.201800196

DO - 10.1002/srin.201800196

M3 - Article

AN - SCOPUS:85054197987

VL - 89

JO - Steel research international

JF - Steel research international

SN - 1611-3683

IS - 10

M1 - 1800196

ER -