Search

Your search keyword '"Kannengießer, Thomas"' showing total 351 results
Start Over Author "Kannengießer, Thomas"
351 results on '"Kannengießer, Thomas"'

111. Welding residual stresses in 960MPa grade QT and TMCP high-strength steels

Author

Schaupp, Thomas, Schroepfer, Dirk, Kromm, Arne, and Kannengiesser, Thomas

Abstract

High-strength steels with yield strengths≥690MPa are becoming increasingly significant for modern steel constructions. Both quenched and tempered (QT) high-strength steels and steels produced by the thermo-mechanically controlled process (TMCP) are currently available. TMCP-steels are usually provided with a typical mill scale. Apart from the manufacturing process these steels differ also in their chemical composition. The influence of these differences are investigated here with focus on the residual stresses formed during TIG welding. Bead on plate welds have shown characteristic residual stress distributions depending on the type of steel as well as on the heat input and preheat temperature. The following work demonstrates that the fluid flow, induced by the elements present in the mill scale, leads to a deeper penetration of the material. This can also lead to increased residual stresses in the surface of the weld and the HAZ. Furthermore, higher heat input and preheat temperature can induce higher tensile residual stresses − which are evident in the present study.

Published
2017
Full Text
View/download PDF

121. FrontMatter.

Author

Kannengiesser, Thomas, Suresh Babu, Sudarsanam, Komizo, Yu-ichi, and Ramirez, Antonio J.

Published
2010

122. Einfluss der Wärmeführung auf die Wasserstoffkonzentration in geschweißten höherfesten Feinkornbaustählen beim Einsatz modifizierter Sprühlichtbogenprozesse.

Author

Schaupp, Thomas, Kannengießer, Thomas, Burger, Stefan, Zinke, Manuela, and Jüttner, Sven

Abstract

Copyright of Schweissen und Schneiden is the property of DVS Media GmbH and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Published
2018

123. Effect of alloy modification on the wear protection coatings made of Ni- and Co-based materials and surface machinability via ultrasonic milling process.

Author

Willeke, Maraike, Giese, Marcel, Lorenz, Swenja, Treutler, Kai, Schröpfer, Dirk, Wesling, Volker, and Kannengießer, Thomas

Subjects
*ULTRASONIC welding, *PLANT engineering, *SURFACES (Technology), *WEAR resistance, *PLASMA arcs, *MACHINABILITY of metals
Abstract

Wear-resistant coatings are required for highly efficient and economical steel components in equipment, process, and power plant engineering to withstand high corrosive, tribological, thermal, and mechanical stresses. Co-alloys are used as wear-resistant coatings for steel components, tailored to the specific application. The substitutability of Co alloys with Ni-based wear protection systems, in addition to price and supply uncertainties, is facilitated by the combination of innovative welding and machining processes such as ultrasonic-assisted milling. The aim of the study is to improve the machinability of two different hard-facing alloys while maintaining the same wear protection potential. Therefore, the wear-resistant alloys NiMoCrSi (Colmonoy C56) and CoMnCrSi (Tribaloy T400) were modified by the alloying additions Nb, Hf, and Ti and then applied to a carbon-manganese steel S355 using the plasma transfer arc (PTA) welding process. The influence of the alloying additions on the microstructure as well as on the formation of the hard phases of the build-up welds is compared. For example, the inclusion of the alloying element Nb results in the formation of a more refined hard phase and reduces the machining force required for C56 and T400. In most cases, the wear resistance potential has been maintained. In order to improve the machinability of the hard facings, the optimization of the demanding machining conditions by alloy modifications of the Co- and Ni-based alloys is also presented. It is shown that some of the modified alloys have significantly better machinability than the conventional alloy. [ABSTRACT FROM AUTHOR]

Published
2025
Full Text
View/download PDF

124. Characterizing PHASE TRANSFORMATIONSof different LTT alloys and their effect on RESIDUAL STRESSESand COLD CRACKING

Author

Kromm, Arne and Kannengiesser, Thomas

Abstract

Novel martensitic filler materials with specially adjusted martensite start temperatures (Ms) can counteract the cooling specific shrinkage due to expansion effects of the weld metal associated with phase transformations. That can be exploited to create compressive residual stresses in the weld and adjacent areas, i.e. beneficial for increasing fatigue strength. The Ms-temperature is shifted via the chemical composition, mainly by the alloying elements nickel and chromium, resulting as well in different retained austenite contents. Investigations were made using different Low Transformation Temperature (LTT) alloys with varying nickel content. The resulting phase transformation temperatures were — for the first time — detected using high energy synchrotron diffraction and Single Sensor Differential Thermal Analysis (SS-DTA). Compared to angle dispersive diffraction, energy dispersive diffraction offers the possibility to measure residual stresses of the martensite and austenite phase parallel fast in one experiment up to depths of 100 μm. The residual stresses show significant distributions dependent on the Ms-temperature. The effect on the cold cracking behaviour of these alloys was investigated using the Tekken test. Results show that cold cracking can be avoided when appropriate contents of retained austenite are existent.

Published
2011
Full Text
View/download PDF

125. Challenges when welding components made of higher-strength fine-grained structural steels.

Author

Kannengießer, Thomas

Subjects
STRUCTURAL steel welding, HEAT conduction, INDUSTRIAL cooling, METALLURGICAL analysis, MATERIALS at high temperatures, STEEL fracture
Abstract

The increased application of higher-strength steels and filler materials necessitates more profound understanding of the interaction between the welding process, the heat input, the cooling conditions and the resulting metallurgical processes in the weld and its surroundings. Strategies which help to improve the strength properties and life-time of welded structures to such an extent that the utilisation of higher-strength materials can be justified and their lightweight construction potential can thus be exploited to the full can only be derived from the interaction between all the influencing factors. Examples of a few investigations on welded joints between higher-strength fine-grained structural steels with regard to the interactions between the main variables influencing the cold cracking are presented in this article. [ABSTRACT FROM AUTHOR]

Published
2014

126. In situ chemical analysis of duplex stainless steel weld by laser induced breakdown spectroscopy.

Author

Quackatz, Lukas, Gornushkin, Igor, Griesche, Axel, Kannengiesser, Thomas, Treutler, Kai, and Wesling, Volker

Subjects
*STAINLESS steel welding, *LASER-induced breakdown spectroscopy, *DUPLEX stainless steel, *LASER welding, *ANALYTICAL chemistry, *STAINLESS steel
Abstract

The high corrosion resistance and good mechanical properties of duplex stainless steel (DSS) are due to its special chemical composition, which is a balanced phase ratio of ferrite (α) and austenite (γ). Many industrial applications require the integration of DSS components. For this, Gas tungsten arc welding (GTAW) is an excellent choice, as it allows an automated operation with high reproducibility. However, when the weld pool solidifies, critical ratios of α- and γ- phases can occur, which lead to solidification cracking, increased susceptibility to corrosion, and a decrease in ductility and critical strength. Previous studies have shown that these defects can be caused by the accumulation of manganese and chromium in the heat affected zone (HAZ), requiring ongoing monitoring of this accumulation. A suitable method for such monitoring is laser-induced breakdown spectroscopy (LIBS), which can be used in two operating modes: calibration using standard reference samples and calibration-free. Unlike conventional quantitative LIBS measurements, which require reference samples to generate a calibration curve, calibration-free LIBS (CF-LIBS) allows chemical compositions to be determined solely from the emission spectrum of the plasma. Numerous publications show that CF-LIBS is a fast and efficient analytical method for the quantitative analysis of metal samples. In this work, CF-LIBS is applied to spectra obtained during GTAW DSS welding and the result is compared with those obtained by PLS analysis. A good correlation was found between both types of analysis, demonstrating the suitability of the CF-LIBS method for this application. The CF-LIBS method has a significant advantage over conventional LIBS due to the rapid in situ measurement of concentrations of major alloying elements without calibration procedure. This, combined with fast feedback and appropriate adjustment of welding parameters, helps prevent welding defects. [Display omitted] • Chemical composition of Steels can be controlled during welding with CF-LIBS. • Results of CF-LIBS are compared with PLS with satisfactory correlation. • Burn-off of alloying elements during welding can be monitored with CF-LIBS. • Weld microstructure can be correlated with in situ chemical concentrations. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results