TY - BOOK

T1 - Untersuchungen zum Verformungs- und Umwandlungsverhalten mikrolegierter Feinkornbaustähle

AU - Windhager, Michael

PY - 1989/12/15

Y1 - 1989/12/15

N2 - Thermomechanical rolling of microalloyed high strength low alloy (HSLA) steels can be simulated by hot tension, hot compression and hot torsion tests. To obtain mechanical properties of transformed materials, the thermomechanical rolling must be simulated by plain strain compression test. In this work, the inhomogeneous deformation distribution in cylindrical and flat compression test specimens has been studied using FEM data of the literature. It was possible to localize regions with a certain degree of deformation in the specimens and to find out correlations between local deformation, recrystallization and transformation behaviour after hot working. The results of recrystallization tests are 3-dimensional diagrams of the mean austenite grain size after hot deformation depending on the temperature and degree of deformation showing regions of full, partial and zero recrystallization. The studies of the transformation behaviour of microalloyed steels after deformation result in 3-dimensional diagrams which show the amount of transformation products such as ferrite, pearlite, bainite and Martensite-Austenite-Constituents depending on the cooling rate and the degree of local deformation. The mechanical properties of thermomechanically treated microalloyed steels were studied by tensile and notched bar impact tests. Using mean values of microstructural composition finally allowed to correlate strength and toughness with microstructure and lead to a good understanding of the mechanical properties of microalloyed steels after simulated thermomechanical rolling. (Author, shortened by G.Q.).

AB - Thermomechanical rolling of microalloyed high strength low alloy (HSLA) steels can be simulated by hot tension, hot compression and hot torsion tests. To obtain mechanical properties of transformed materials, the thermomechanical rolling must be simulated by plain strain compression test. In this work, the inhomogeneous deformation distribution in cylindrical and flat compression test specimens has been studied using FEM data of the literature. It was possible to localize regions with a certain degree of deformation in the specimens and to find out correlations between local deformation, recrystallization and transformation behaviour after hot working. The results of recrystallization tests are 3-dimensional diagrams of the mean austenite grain size after hot deformation depending on the temperature and degree of deformation showing regions of full, partial and zero recrystallization. The studies of the transformation behaviour of microalloyed steels after deformation result in 3-dimensional diagrams which show the amount of transformation products such as ferrite, pearlite, bainite and Martensite-Austenite-Constituents depending on the cooling rate and the degree of local deformation. The mechanical properties of thermomechanically treated microalloyed steels were studied by tensile and notched bar impact tests. Using mean values of microstructural composition finally allowed to correlate strength and toughness with microstructure and lead to a good understanding of the mechanical properties of microalloyed steels after simulated thermomechanical rolling. (Author, shortened by G.Q.).

KW - Mikrolegierung

KW - Verformung

KW - Umwandlung

KW - Stahl

KW - Microalloying

KW - Deformation

KW - Transformation

KW - Steels

M3 - Dissertation

ER -