Rosch S.,Georgsmarienhutte GmbH |
Trojahn W.,Schaeffler Group |
Clausen B.,University of Bremen
HTM - Journal of Heat Treatment and Materials | Year: 2016
The performance of large case hardened rolling contact bearings is dependent on the properties of the surface layers of the rolling partners subjected to strain. This is especially true under challenging conditions like poor lubrication and/or overrolling of particles. Those properties are mainly affected by the chemical composition of the base alloyed steel and the amount and distribution of induced carbon respectively carbon and nitrogen (carbonitriding). For optimization purposes 11 case-hardening or tempering steels were carbonitrided under varying gas compositions towards approximately equal hardening depths. The surface layers were characterized and chosen states of texture were tested for thermal and mechanical stability. Conclusively capability tests for rolling contact bearings were conducted by overrolling tests of discs and angular ball bearings under varying overrolling conditions. The best overall test results with regard to production costs were achieved by the carbonitrided air melted steel grade 32MnCrMo6-4-3. © 2016 Carl Hanser Verlag GmbH & Co. KG.
Schwerdt D.,State Materials Testing Institute Darmstadt |
Kaiser B.,State Materials Testing Institute Darmstadt |
Wuttke U.,State Materials Testing Institute Darmstadt |
Hoche H.,State Materials Testing Institute Darmstadt |
And 3 more authors.
Materials Science and Technology Conference and Exhibition 2013, MS and T 2013 | Year: 2013
A key benefit of bainitic steels is cost reduction for heat treatment in comparison to traditionally quenched and tempered steels due to absence of one heat treatment step. Nevertheless, new alloying concepts are necessary to ensure success of bainitic microstructures for massive parts. Therefore, the innovative microalloyed bainitic steel 12CrMnMoV7-5 mod, which features a new alloying concept, was subjected to controlled cooling from forging temperature to obtain a bainitic microstructure. All investigations of properties and microstructure were done in comparison to a conventionally quenched and tempered steel 42CrMo4. The aim of this research project was to verify the capability of the microalloyed bainitic steel 12CrMnMoV7-5 mod for forged parts which have to endure cyclic loading. Investigations comprised mechanical properties including static and cyclic fracture mechanics as well as fatigue behavior of smooth and notched specimens. The microstructure-properties correlation was examined by visible-light microscopy (VLM), scanning electron microscopy (SEM) and Electron Back Scatter Diffraction-method (EBSD). Copyright © 2013 MS&T'13®.
Jansen T.,University of Hamburg |
Kruger K.,University of Hamburg |
Schliephake H.,Geschaftsfuhrer Technik |
Dettmer Und B.,Leitung Schmelzbetrieb |
Deng J.,Georgsmarienhutte GmbH
Stahl und Eisen | Year: 2010
Based on the acoustic sound emission and the electrical parameters, an algorithm for foaming slag detection at a DC-EAF is presented. Regardless of the currently applied electrical power, the model provides a reliable estimate of the slag level. Empirical studies at the DC-EAF of the Georgsmarienhütte GmbH demonstrate the applicability of the signal as a slag index. Thus a robust tool is given to detect a poorly shielded arc at an early stage. In a second step the slag signal was integrated into an existing power control concept. Aim is to adjust power input dynamically to the process conditions.
Bandusch L.,AcelorMittal Hamburg GmbH |
Dettmer B.,Georgsmarienhutte GmbH |
Fandrich R.,Steel Institute VDEh |
Kleimt B.,VDEh Betriebsforschungsinstitut GmbH |
And 3 more authors.
Stahl und Eisen | Year: 2012
After the major decline in 2009, the European steel industry is still struggling to reach the pre-crisis level. The steel production with EAF is under constant improvement which can be seen by an increase in efficiency. Examples thereof are process automation as well as the use of off-gas energy for scrap preheating or steam generation. Simultanously, the performance of new plants is also increasing. One crucial challenge for the future of the European steel industry, if not today already, is the availability of electrical energy. Weak distribution grids as well as rising electricity prices are at hand.
Schliephake H.,Georgsmarienhutte GmbH |
Born C.,Tenova Re Energy GmbH |
Granderath R.,Tenova Re Energy GmbH |
Memoli F.,Tenova Core Chernngton Corporate Center |
Simmons J.,Tenova Core Chernngton Corporate Center
Steel Times International | Year: 2011
Evaporative Cooling System (ECS), well established on oxygen converters and reheat furnaces, has been applied to EAF flue gas cooling at Georgsmarienhütte (GMH) in Germany to generate steam for the VOD station thereby enabling closure of the boiler house. One main challenge was to smooth out the steam output and efficiently handle the energy peaks. The whole ECS was designed slightly bigger than required for cooling purposes, therefore additional amount of water had an excess stored energy capacity. In the GMH system the temperature moves between 105°C and 159°C during the peaks of the power-on time. A waste heat boiler must be used to recover the energy for temperatures between 600°C and an inlet temperature of 180-250°C.