Johannes Lohmar

Dr. Johannes Lohmar

orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 August 2020 in Journal of Materials Processing Technology
Verified
Journal Article
Open access
JLJohannes Lohmar
Johannes Lohmar
CCC.J. Cleaver
C.J. Cleaver
JAJ.M. Allwood
J.M. Allwood

1 June 2021 in Journal of Materials Processing Technology
Verified
Journal Article
Open access
CCChristopher John Cleaver
Christopher John Cleaver
JLJohannes Lohmar
Johannes Lohmar
STSaeed Tamimi
Saeed Tamimi

1 January 2018 in CIRP Annals
Verified
Journal Article
Closed access
SSSven Stockert
Sven Stockert
MWMatthias Wehr
Matthias Wehr
JLJohannes Lohmar
Johannes Lohmar
GHGerhard Hirt
Gerhard Hirt
DADirk Abel
Dirk Abel

14 January 2020 in Production Engineering
Verified
Journal Article
Open access
PDF file
GHGerhard Kurt Peter Hirt
Gerhard Kurt Peter Hirt
ATA. Erman Tekkaya
A. Erman Tekkaya
TCTill Clausmeyer
Till Clausmeyer
JLJohannes Lohmar
Johannes Lohmar
In modern process design of metallic components, the influence of the metal forming process on the component properties can be taken into account. However, damage occurring concurrent to forming cannot be accounted for yet. Due to the complex multi-scale, multi-mechanism nature of damage, it is very challenging to predict its evolution through any metal forming process chain. In order to enable such damage controlled forming processes in the future three research questions need to be addressed in detail: How are the mechanisms governing the damage initiation and evolution in metals best characterized? How can the damage mechanisms be described and the damage evolution be predicted using models? How do forming processes influence the damage evolution? Answering these questions and considering damage during process design will in the long term lead to improved lightweight components that do not require conventional safety factors, as their performance is already fully known.

12 November 2021 in Materials
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Journal Article
Open access
PDF file
XWXuefei Wei
Xuefei Wei
AKAlexander Krämer
Alexander Krämer
GHGerhard Kurt Peter Hirt
Gerhard Kurt Peter Hirt
ASAnett Stöcker
Anett Stöcker
Rudolf KawallaRudolf Kawalla
Rudolf Kawalla
JLJohannes Lohmar
Johannes Lohmar
The magnetic properties of non-oriented electrical steel, widely used in electric machines, are closely related to the grain size and texture of the material. How to control the evolution of grain size and texture through processing in order to improve the magnetic properties is the research focus of this article. Therefore, the complete process chain of a non-oriented electrical steel with 3.2 wt.-% Si was studied with regard to hot rolling, cold rolling, and final annealing on laboratory scale. Through a comprehensive analysis of the process chain, the influence of important process parameters on the grain size and texture evolution as well as the magnetic properties was determined. It was found that furnace cooling after the last hot rolling pass led to a fully recrystallized grain structure with the favorable ND-rotated-cube component, and a large portion of this component was retained in the thin strip after cold rolling, resulting in a texture with a low γ-fiber and a high ND-cube component after final annealing at moderate to high temperatures. These promising results on a laboratory scale can be regarded as an effective way to control the processing on an industrial scale, to finally tailor the magnetic properties of non-oriented electrical steel according to their final application.

1 January 2017 in Procedia Engineering
Verified
Journal Article
Open access
AQAngela Quadfasel
Angela Quadfasel
JLJohannes Lohmar
Johannes Lohmar
GHGerhard Hirt
Gerhard Hirt