scholarly journals Characterization of Phase Transformations During Graded Thermo-Mechanical Processing of Press-Hardening Sheet Steel 22MnB5

2020 ◽  
Vol 51 (11) ◽  
pp. 5628-5638
Author(s):  
A. Reitz ◽  
O. Grydin ◽  
M. Schaper
Keyword(s):  
Phase Transformations ◽  
Sheet Steel ◽  
Steel Specimen ◽  
High Strength ◽  
High Energy ◽  
Mechanical Processing ◽  
Press Hardening ◽  
Flat Steel ◽  
High Energy Absorption ◽  
Press Hardening Steel

Abstract Safety-relevant components in automobiles require materials that combine high strength with sufficient residual ductility and high-energy absorption. A graded thermo-mechanical treatment of the press-hardening steel 22MnB5 with graded microstructure can provide a material with such properties. Different austenitization temperatures, cooling and forming conditions within a sheet part lead to the development of microstructures with mixed phase compositions. To determine the resulting phase contents in such graded processed parts, a large number of dilatometric tests are usually required. With a non-contact characterization method, it is possible to detect local phase transformations on an inhomogeneously treated flat steel specimen. For press-hardening steel after heat treatment and thermo-mechanical processing, correlations between austenitization temperature, hot deformation strain, microstructure, and hardness are established.

Influence of Chromium and Niobium on the Press-Hardening Process of Multiphase Low-Alloy TRIP Steels

2021 ◽  
Vol 1016 ◽  
pp. 636-641
Author(s):  
Hana Jirková ◽  
Jiří Vrtáček ◽  
Michal Peković ◽  
Tomáš Janda ◽  
Ludmila Kučerová
Keyword(s):  
Retained Austenite ◽  
High Energy ◽  
Experimental Program ◽  
Chemical Compositions ◽  
Body Parts ◽  
Press Hardening ◽  
Trip Steels ◽  
Forming Technology ◽  
Suitable Heat Treatment ◽  
High Energy Absorption

Press-hardening is an intensively developing forming technology which is mainly used for the production of car body parts. Because it is a hot forming technology, small forming forces can be utilized and, due to the lower spring-back effect, more accurate products are achieved. In car bodies, materials with high energy absorption and a sufficient hardening coefficient are mainly used in impacted parts. One of these materials is TRIP multiphase steels with different chemical composition. In these steels, it is possible to achieve an ultimate strength up to 1000 MPa with the ductility of 20-30%. In order to achieve the desired properties, it is necessary to select a suitable heat treatment that allows to achieve a multiphase structure. Phase transformations and mechanical properties are influenced by the use of suitable alloying elements. Three low-alloy, multiphase TRIP steels with different chemical compositions with a carbon content of 0.2% were chosen for the experimental program. The first steel was alloyed only with manganese and silicon, in the second niobium was added, and in the third the influence of chromium on increase of hardenability and strength was investigated. Press-hardening was performed in a heated forming tool. To describe the effect of the cooling rate, the forming was carried out in a tool at room temperature and after preheating to 425°C. The influence of holding time in the tool at 425°C to support the formation of bainite and retained austenite stabilization was also investigated. Mixed ferritic-bainitic-martensitic structures with some retained austenite content were obtained.

Process Optimization of 3D Optical Fiber Laser Cutting Robot for Press Hardening of UHSS

2013 ◽  
Vol 753-755 ◽  
pp. 2033-2036 ◽  
Author(s):  
Hui Qiang Liu ◽  
Yi Sheng Zhang ◽  
Pei Xing Liu
Keyword(s):  
Laser Cutting ◽  
3D Model ◽  
Complex Structure ◽  
High Strength ◽  
High Energy ◽  
Entry Point ◽  
Press Hardening ◽  
Energy Beam ◽  
Cutting Head ◽  
Offline Programming

The hot forming parts of high strength steel are difficult to cut with the presses and the traditional high-energy beam due to its high tensile strength which can be up to 1500Mpa and its complex structure. And the 3D laser cutting is an effective way to solve the problem. However some problems in the laser process affect the efficiency and quality seriously, including interference between the robot arms and the cutting head with the untrimmed parts, difficulty in determining the entry point and over burning etc. In this research three measures are taken to cut the anti-collision beam, including using photogrammetric technology to get its uncutted 3D model for offline programming to avoid interference, selecting appropriate entry point to trim without interrupt, amending normals and adjusting the process parameters at corners to prevent over burning. The results show that the efficiency and quality are improved and a creative new offline programming method is put forward.

Influence of vanadium on the hydrogen embrittlement of aluminized ultra-high strength press hardening steel

2018 ◽  
Vol 735 ◽  
pp. 448-455 ◽  
Author(s):  
Lawrence Cho ◽  
Eun Jung Seo ◽  
Dimas H. Sulistiyo ◽  
Kyoung Rae Jo ◽  
Seong Woo Kim ◽  
...  
Keyword(s):  
Hydrogen Embrittlement ◽  
High Strength ◽  
Press Hardening ◽  
Press Hardening Steel

Effects of Austenitizing Temperature on Microstructure and Properties of Hot-Formed Steel

2014 ◽  
Vol 1063 ◽  
pp. 88-92 ◽  
Author(s):  
He Long Cai ◽  
Peng Ju Du ◽  
Hong Liang Yi ◽  
Di Wu
Keyword(s):  
Mechanical Properties ◽  
Hot Stamping ◽  
High Strength ◽  
Hardened Steel ◽  
Austenitizing Temperature ◽  
Austenitization Temperature ◽  
Press Hardening ◽  
Automotive Structures ◽  
Body In White ◽  
Press Hardening Steel

Press hardening steel is the best solution for application of extremely high strength steel in automotive structures in order to reduce the weight of body-in-white. Effect of austenitizing temperature on the grain coarsening of a press hardening steel has been investigated by using dilatometer at first. The mechanical properties of press-hardened steel austenitized at temperature between 850 to 950oC by using a pilot hot stamping line have been investigated. The strength, especially the ultimate tensile strength, was improved by the grain refinement with lower austenitization temperature.

scholarly journals Microstructure transformations in a press hardening steel during tailored thermo‐mechanical processing

2021 ◽  
Author(s):  
Hendrik Westermann ◽  
Alexander Reitz ◽  
Rolf Mahnken ◽  
Mirko Schaper ◽  
Olexandr Grydin
Keyword(s):  
Mechanical Processing ◽  
Press Hardening ◽  
Press Hardening Steel
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