TY - THES

T1 - Investigation of the castability and the crack sensitivity of high alloyed steels

AU - Wiener, Jakob

N1 - embargoed until null

PY - 2006

Y1 - 2006

N2 - Improved requirements on mechanical behavior and lightweight of steels are forcing the steel industry to research in alternative alloying concepts. High alloyed TWIP steels with extraordinary compositions like 25% Mn, are a promising way to fulfill these requirements and to succeed in the competition of materials. These TWIP steels are still in a stadium of research. On the one side, the advantageous mechanical properties are already well documented in literature, but on the other side, information about the production of these steels can seldom be found. The aim of this work is the investigation of the castability of two high alloyed TWIP steels in contrast to three reference grades (TRIP-RA, silicon strip, and ULC steel) which are already in production. The castability is related to mechanical high temperature properties, crack sensitivity, and steel cleanness. The SSCT (submerged split chill tensile) device is used to receive the experimental data. The test allows different casting techniques to be mimicked, when the coating thickness of the test body is changed. By doing so, solidification conditions similar to those of slab casting as well as solidification conditions similar to those of thin strip casting can be reached. Phase diagrams are used to bring light into the solidification behavior of the different steels. The test material from the SSCT experiment is metallographically analyzed by taking into special consideration the crack susceptibility and steel cleanness.

AB - Improved requirements on mechanical behavior and lightweight of steels are forcing the steel industry to research in alternative alloying concepts. High alloyed TWIP steels with extraordinary compositions like 25% Mn, are a promising way to fulfill these requirements and to succeed in the competition of materials. These TWIP steels are still in a stadium of research. On the one side, the advantageous mechanical properties are already well documented in literature, but on the other side, information about the production of these steels can seldom be found. The aim of this work is the investigation of the castability of two high alloyed TWIP steels in contrast to three reference grades (TRIP-RA, silicon strip, and ULC steel) which are already in production. The castability is related to mechanical high temperature properties, crack sensitivity, and steel cleanness. The SSCT (submerged split chill tensile) device is used to receive the experimental data. The test allows different casting techniques to be mimicked, when the coating thickness of the test body is changed. By doing so, solidification conditions similar to those of slab casting as well as solidification conditions similar to those of thin strip casting can be reached. Phase diagrams are used to bring light into the solidification behavior of the different steels. The test material from the SSCT experiment is metallographically analyzed by taking into special consideration the crack susceptibility and steel cleanness.

KW - TWIPe

KW - TRIP

KW - nichtmetallische Einschlüsse

KW - TWIP

KW - TRIP

KW - non-metallic inclusions

M3 - Diploma Thesis

ER -