TY - THES

T1 - Optimization of the process route of seamless steel tubes to increase the mechanical - technological properties

AU - Gruber, Christian

N1 - embargoed until 01-09-2023

PY - 2018

Y1 - 2018

N2 - An intermediate cooling of tube blanks after the push bench in the seamless tube production process shows increased mechanical-technological properties on the final product. An analysis on grain size and microstructure development and an evaluation of the occurring phenomena of possible precipitations are tested on three different steel grades of intermediate cooled samples in comparison to traditionally processed tubes. Furthermore, spray water quenched tube blanks are reviewed by means of an increase of productivity during intermediate cooling. A complete mechanical – technological profile of the different steel grades was built with included assessment on recrystallized fractions during deforming and precipitation effects on strength, toughness and grain size development. Also the influence of the varying austenite grain sizes on the CCT diagram and following on the phase transformation kinetics has been observed in detail. The results from the trials give a recommendation on the optimal process route for thermomechanical treated seamless tubes with a perfect initial state for rapid cooled AHSS advanced high strength steel tubes.

AB - An intermediate cooling of tube blanks after the push bench in the seamless tube production process shows increased mechanical-technological properties on the final product. An analysis on grain size and microstructure development and an evaluation of the occurring phenomena of possible precipitations are tested on three different steel grades of intermediate cooled samples in comparison to traditionally processed tubes. Furthermore, spray water quenched tube blanks are reviewed by means of an increase of productivity during intermediate cooling. A complete mechanical – technological profile of the different steel grades was built with included assessment on recrystallized fractions during deforming and precipitation effects on strength, toughness and grain size development. Also the influence of the varying austenite grain sizes on the CCT diagram and following on the phase transformation kinetics has been observed in detail. The results from the trials give a recommendation on the optimal process route for thermomechanical treated seamless tubes with a perfect initial state for rapid cooled AHSS advanced high strength steel tubes.

KW - nahtloses Rohr

KW - thermomechanisch

KW - mikrolegiert

KW - Phasenumwandlung

KW - ZTU

KW - Korngröße

KW - Kornwachstum

KW - Rekristallisation

KW - Austenit

KW - Ferrit

KW - Gefüge

KW - Festigkeitssteigerung

KW - Ausscheidungen

KW - Karbid

KW - Nitrid

KW - Karbonitrid

KW - seamless tube

KW - thermomechanical

KW - microalloy

KW - phase transformation

KW - CCT

KW - grain size

KW - grain growth

KW - recrystallization

KW - austenite

KW - ferrite

KW - microstructure

KW - strengthening mechanism

KW - precipitation

KW - carbide

KW - nitride

KW - carbonitride

U2 - 10.34901/mul.pub.2023.273

DO - 10.34901/mul.pub.2023.273

M3 - Master's Thesis

ER -