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5 results on '"Alexander Gramlich"'

1. Air-Hardening Die-Forged Con-Rods—Achievable Mechanical Properties of Bainitic and Martensitic Concepts

Author

Alexander Gramlich, Robert Lange, Udo Zitz, and Klaus Büßenschütt

Subjects
high-strength steels, forging, air-cooling, mechanical properties, microstructure, Mining engineering. Metallurgy, TN1-997
Abstract

Three air-hardening forging steels are presented, concerning their microstructure and their mechanical properties. The materials have been produced industrially and achieve either bainitic or martensitic microstructures by air-cooling directly from the forging heat. The bainitic steels are rather conservative steel concepts with an overall alloy concentration of approximately 3 wt.%, while the martensitic concept is alloyed with 4 wt.% manganese (and additional elements), and therefore belongs to the recently developed steel class of medium manganese steels. The presented materials achieve high strengths (YS: 720 MPa to 850 MPa, UTS: 1055 MPa to 1350 MPa), good elongations (Au: 4.0% to 5.9%, At: 12.3% to 14.9%), and impact toughnesses (up to 37 J) in the air-hardened condition. It is shown that air-hardened steels achieve properties close to standard Q + T steels, while being produced with a significantly reduced heat treatment.

Published
2022
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2. Austenite Reversion Tempering-Annealing of 4 wt.% Manganese Steels for Automotive Forging Application

Author

Alexander Gramlich, Robin Emmrich, and Wolfgang Bleck

Subjects
medium-manganese, forging, austenite reversion, mechanical properties, microstructure, Mining engineering. Metallurgy, TN1-997
Abstract

New medium Mn steels for forged components, in combination with a new heat treatment, are presented. This new annealing process implies air-cooling after forging and austenite reversion tempering (AC + ART). This leads to energy saving compared to other heat treatments, like quenching and tempering (Q + T) or quenching and partitioning (Q + P). Furthermore, the temperature control of AC + ART is easy, which increases the applicability to forged products with large diameters. Laboratory melts distinguished by Ti, B, Mo contents have been casted and consecutively forged into semi-finished products. Mechanical properties and microstructure have been characterized for the AC and the AC + ART states. The as forged-state shows YS from 900 MPa to 1000 MPa, UTS from 1350 MPa to 1500 MPa and impact toughness from 15 J to 25 J. Through the formation of nanostructured retained metastable austenite an increase in impact toughness was achieved with values from 80 J to 100 J dependent on the chemical composition.

Published
2019
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3. Influence of Alloying Elements on the Dynamic Recrystallization of 4 wt.-% Medium Manganese Steels

Author

Alexander Gramlich, Ulrich Krupp, and Hanne Schäfers

Subjects
Materials science, 0211 other engineering and technologies, Niobium, chemistry.chemical_element, 02 engineering and technology, Manganese, lcsh:Technology, Forging, Article, hot deformation, General Materials Science, forging steels, lcsh:Microscopy, 021102 mining & metallurgy, lcsh:QC120-168.85, lcsh:QH201-278.5, lcsh:T, Metallurgy, Strain hardening exponent, flow curves, 021001 nanoscience & nanotechnology, Microstructure, chemistry, lcsh:TA1-2040, Martensite, medium manganese steels, Dynamic recrystallization, lcsh:Descriptive and experimental mechanics, lcsh:Electrical engineering. Electronics. Nuclear engineering, Deformation (engineering), 0210 nano-technology, lcsh:Engineering (General). Civil engineering (General), ddc:600, lcsh:TK1-9971
Abstract

The hot deformation behaviour of air-hardening martensitic forging steels (of type 1.5132) is presented. The newly developed steels are characterized through dilatometric tests as well as through microstructure analyses with LOM and SEM and hardness measurements. Additionally, the influence of alloying elements on the flow curves at high temperatures is discussed. It is demonstrated that the higher alloying content does not increase the equivalent stresses in comparison to the reference alloys and contrariwise reduces the offset for dynamic recrystallization at temperatures below 1100 ∘C. Furthermore, the effect of different alloying elements on the strain hardening behaviour during hot compression of 4wt.&ndash, % medium manganese steels is presented. It is shown that boron reduces the offset for dynamic recrystallization if present in solid solution, while the combined addition of titanium and niobium annihilates the solid drag effect on the prior austenite grain boundaries.

Published
2020

4. Austenite Reversion Tempering-Annealing of 4 wt.% Manganese Steels for Automotive Forging Application

Author

Wolfgang Bleck, Robin Emmrich, and Alexander Gramlich

Subjects
lcsh:TN1-997, Materials science, Annealing (metallurgy), microstructure, chemistry.chemical_element, 02 engineering and technology, Manganese, mechanical properties, 01 natural sciences, Forging, austenite reversion, forging, 0103 physical sciences, ddc:530, General Materials Science, Tempering, Chemical composition, lcsh:Mining engineering. Metallurgy, 010302 applied physics, Austenite, medium-manganese, Impact toughness, Metallurgy, Metals and Alloys, 021001 nanoscience & nanotechnology, Microstructure, chemistry, 0210 nano-technology
Abstract

Physical Metallurgy of High Manganese Steels / Special Issue Editors: Wolfgang Bleck, Christian Haase; Basel : MDPI, Metals 134-143 (2019)., Published by MDPI, Basel

Published
2019
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5. Development of air-hardening martensitic forging steels

Author

Tobias Schmiedl, Alexander Gramlich, Tobias Melz, Wolfgang Bleck, and Steffen Schönborn

Subjects
Toughness, Materials science, Mechanical Engineering, Metallurgy, Alloy, technology, industry, and agriculture, 0211 other engineering and technologies, Charpy impact test, 02 engineering and technology, engineering.material, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Microstructure, Fatigue limit, Forging, Mechanics of Materials, Hardening (metallurgy), engineering, General Materials Science, 0210 nano-technology, 021102 mining & metallurgy, Tensile testing
Abstract

A new alloy design for air-hardening forging steels has been investigated. Five laboratory melts with C contents between 0.15 and 0.19 wt.−% and a Mn content of 4 wt.−% distinguished by their Al (0.03/0.50), Ti (-/0.02), B (-/0.005), Mo (-/0.20) contents have been laboratory casted and forged into rectangular blocks with a cross section of 60 x 60 mm. After air cooling the tensile test properties, the Charpy toughness and the fatigue properties have been determined and compared to a Q+T steel as reference material. While the static mechanical properties are comparable to the reference grade, a small decrease in toughness and a significant increase in fatigue strength have been obtained. These findings are discussed with respect to the role of the individual alloying elements and their impact on microstructure and precipitation state.

Published
2020

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