Niobelcon BVBA

Schilde, Belgium

Niobelcon BVBA

Schilde, Belgium

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Mohrbacher H.,NiobelCon Bvba
International Conference on Advances in Metallurgy of Long and Forged Products | Year: 2015

Increasing demands with regard to performance of carburizing steels necessitate the further development of process technology as well as steel metallurgy. The present paper exemplifies recent developments based on alloy modifications with microalloying elements. The focus is thereby on molybdenum alloyed carburizing grades. A dedicated addition of niobium enables better mechanical properties and higher carburizing temperatures. Simultaneously the carburizing time can be shortened and distortion by heat treatment is being reduced, as the microstructure exhibits a more homogeneous grain size distribution. Further development potential offered by microalloying in carburizing steels is seen in an improved toughness due to the finer sized grain structure allowing to produce higher strength and more economical steel. These measures when applied in new steel concepts enable significant cost savings along the entire manufacturing chain especially in the production of larger transmissions. © 2015, Association for Iron and Steel Technology, AISTECH. All rights reserved.


Mohrbacher H.,NiobelCon Bvba | Zhai Q.,Shanghai University
Materials Science and Technology Conference and Exhibition 2011, MS and T'11 | Year: 2011

Niobium when alloyed to hypo- as well as hypereutectic iron has several beneficial metallurgical effects. It refines the eutectic cell size, graphite structure and also the lamellae spacing of the pearlite matrix. Nb affects the nucleation of graphite and can hence support inoculation. It also narrows down the temperature hysteresis between austenite and pearlite formation, which is important to cyclic heating. Finally, the ultra hard NbC particles formed lead to a markedly increased wear resistance of the material. The paper elucidates how these effects of Nb can be used to make brake discs with better properties and demonstrates processing benefits in the production of cast iron. Finally some examples of application in heavy trucks and recent passenger cars are given. Copyright © 2011 MS&T'11®.


Spottl M.,WISCO Lasertechnik GmbH | Mohrbacher H.,NiobelCon bvba
Advances in Manufacturing | Year: 2014

Laser welding is an established manufacturing technology for a large variety of automotive applications due to its attractive properties such as low heat input, high precision and fast welding speed. Especially when welding high strength steels, which are dominantly used in today’s car body construction, the low heat input by laser welding bears significant advantages with regard to the properties of the weld seam. The exploitation of the full application potential of laser welding in mass production requires an appropriate manufacturing concept and corresponding auxiliary technologies. The present paper demonstrates the integration of laser welding into the surrounding manufacturing concepts by a modular setup with different levels of automation. This approach offers flexible solutions for individual needs thereby optimizing investment cost, labor cost and productivity. Recently available laser sources enable exceptionally high welding speed on thin gauged sheet metals but require efficient material handling concepts to utilize the full speed potential. Industrial concepts are presented offering efficient material handling and high process robustness for mass production welding. © 2014 Shanghai University and Springer-Verlag Berlin Heidelberg.


Woydt M.,BAM Federal Institute of Materials Research and Testing | Mohrbacher H.,Niobelcon BVBA
Wear | Year: 2013

The tribological profile of alumina (99.7%) mated against binder-less niobium carbide (NbC) rotating disks were determined unidirectional sliding tests (0.1-7.5m/s; 22°C and 400°C) as well as in oscillation tests (f=20Hz, δx=0.2mm, 2/50/98% rel. humidity, n=105/106 cycles) under un-lubricated (dry) conditions. In addition, the microstructure and mechanical properties of NbC were determined as well. The reason for testing hot-pressed NbC was to avoid side effects generated by sintering additives and/or second phases. The tribological data obtained were benchmarked with different ceramics, cermets and thermally sprayed coatings. NbC exhibited low wear rates under dry sliding associated with high load carrying capacity. The tribological profile established revealed a strong position of NbC under tribological considerations and for closed tribo-systems against traditional references, such as WC, Cr3C2, (Ti,Mo)(C,N), etc. © 2013 Elsevier B.V.


Woydt M.,BAM Federal Institute of Materials Research and Testing | Mohrbacher H.,Niobelcon BVBA
International Journal of Refractory Metals and Hard Materials | Year: 2015

The tribological profile of alumina (99.7%) mated against rotating disks made in binder-less niobium carbide (NbC) and cobalt-bonded NbC were determined under unidirectional sliding tests (0.1 m/s to 8.0 m/s; 22 °C and 400 °C) as well as in oscillation tests (f=20 Hz, Δx=0.2 mm, 2/50/98% rel. humidity, n=105/106 cycles) under unlubricated (dry) conditions. In addition, themicrostructure andmechanical properties of binderless NbC and NbC bonded with 8% cobalt were determined as well. The reason for testing hot-pressed NbC was to avoid side effects generated by sintering additives and/or second phases. The tribological data obtained were benchmarked with different ceramics, cermets and thermally sprayed coatings. NbC and cobalt-bonded NbC exhibited low wear rates under dry sliding associated with high load carrying capacity. The tribological profile established revealed a strong position of NbC bearing materials under tribological considerations and for closed tribo-systems against traditional references, such as WC, Cr3C2 and (Ti,Mo)(C,N). © 2014 Elsevier Ltd.


Woydt M.,BAM Federal Institute of Materials Research and Testing | Mohrbacher H.,Niobelcon BVBA
Ceramic Engineering and Science Proceedings | Year: 2016

The tribological behavior under dry sliding of a Fe3Al-NbC composite prepared by pyrometallurgical synthesis is compared to NbC-based hard metals bonded by cobalt or Fe3A1. The dry sliding wear resistance (0, 1-7/10 m/s) of the present Fe3Al-NbC with ∼60% NbC was close to those known of NbC-based hard metals. No grain pull-outs or fragmentations of the NbC grains were seen in the wear tracks, as a metallurgical interphase was formed between matrix and NbC grains.


Mohrbacher H.,NiobelCon bvba
Energy Materials 2014, Conference Proceedings | Year: 2014

Seamless pipes are available with wall gages of up to 100 mm and outer diameters up to around 700 mm. Such pipes are typically used for oil country tubular goods as well as for structural applications. Due to market requirements the demand for high strength grade seamless pipes is increasing. Many applications need high toughness in addition to high strength. The different rolling processes applied in production depend on wall gage and pipe diameter. The continuous mandrel mill process is used to produce smaller gages and diameters; plug mill processing covers medium gages and diameters; Pilger mill processing allows producing larger diameters and heavy wall gage. In all these processes only a limited degree of thermo-mechanical rolling can be achieved. Therefore strengthening and toughening by severe grain refinement employing a conventional niobium-based microalloying concept is not easily achievable. Accordingly, high strength and toughness seamless pipe is typically produced via a quench and tempering process route. This route however is costly and above that often constitutes a capacity bottleneck in the mill. Innovative low-carbon alloy concepts however do allow producing strength up to grade X70 at very high toughness directly off the rolling plant, i.e., without quench and tempering treatment. Due to the low carbon content also welding is much facilitated. The paper reveals the metallurgical principles, which are based on appropriate niobium and molybdenum alloying. Additionally the paper demonstrates how heavy gaged seamless pipes up to 70 mm wall thickness can be produced based on a low-carbon Nb-Mo approach using quench and temper treatment.


Mohrbacher H.,NiobelCon bvba
Advances in Manufacturing | Year: 2016

Carburized steel grades are widely used in applications where high surface near hardness is required in combination with good core toughness as well as high strength and fatigue resistance. The process of carburizing lower to medium carbon containing steel can generally provide this combination of properties and has been practiced for several decades. Such steel is essential in the vehicle power-train, machines and power generation equipment. However, the increasing performance demands by such applications as well as economical considerations forced steel producers to develop better alloys and fabricators to design more efficient manufacturing processes. The present paper describes recent concepts for alloy design optimization of carburizing steel and demonstrates the forthcoming beneficial consequences with regard to manufacturing processes and final properties. © 2016, The Author(s).


Mohrbacher H.,NiobelCon bvba
7th International Conference on High Strength Low Alloy Steels, HSLA Steels 2015, International Conference on Microalloying 2015, Microalloying 2015 and International Conference on Offshore Engineering Steels 2015, OES 2015 | Year: 2015

Increasing demands with regard to performance of special steels necessitate the further development of process technology as well as steel metallurgy. The present paper exemplifies recent developments based on alloy modifications with microalloying elements enhancing the performance of special steel types. The focus is thereby on molybdenum alloyed carburizing grades that are typically applied e.g. in the powertrain of vehicles, machinery and power generation equipment. A dedicated addition of niobium enables better mechanical properties and higher carburizing temperatures. Simultaneously the carburizing time can be shortened and distortion by heat treatment is reduced, as the microstructure remains more homogeneous. Further development potential offered by microalloying in carburizing steels is seen in an improved toughness due to the finer sized grain structure allowing to produce higher strength and more economical steel. These measures when applied in new steel concepts enable significant cost savings along the entire manufacturing chain especially in the production of larger transmissions. Finally, additional cost savings can be expected by a reduction and optimization of processes and procedures at the end-user.


Mohrbacher H.,NiobelCon bvba
7th International Conference on High Strength Low Alloy Steels, HSLA Steels 2015, International Conference on Microalloying 2015, Microalloying 2015 and International Conference on Offshore Engineering Steels 2015, OES 2015 | Year: 2015

Dual phase steel is widely used in today's car body manufacturing. Its characteristics of high nvalue and good elongation (A80) are the basis of good press formability. However, practical experience has shown unexpected failure in forming operations where tight bending, stretch flanging or hole expansion are predominant. The inhomogeneous microstructure of soft ferrite and hard martensite in combination with highly localized straining is the origin of these problems. Furthermore, weldability and delayed cracking have been experienced to cause problems in ultra-high strength DP steel. Refinement and homogenization of the two-phase microstructure as well as lowering of the carbon content have been identified as remedies to the mentioned problems. However, mill processing of DP steel with reduced carbon content is more difficult especially for the higher strength levels. Niobium microalloying proved to be very effective in increasing the processing window of low-carbon DP steels besides of its natural effect of refining the microstructure. Meanwhile the production of niobium microalloyed DP steel has been established in several markets including China. The paper details the fundamentals, demonstrates respective production concepts and presents examples of application of Nb-microalloyed DP steels.

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