90 Years of Cemented Carbide - Past, Present and Future
Dr Animesh Bose
(Materials Processing, Inc, United States of America)
Dr Leo Prakash
(WTP Materials Engineering, Germany)
Tools and tool materials have been a key to the development of human society. The commercial introduction of durable tools based on Tungsten Carbide - Cobalt 90 years ago has had a profound influence on manufacturing as well as on modern life. WC-Co tools are used in almost all walks of life such as in agriculture, mining, transportation, food and chemical processing, manufacturing of industrial and personal products etc.
This seminar commemorates Ninety Years of Cemented Carbide by highlighting the past, present and future developments in the form of six invited lectures presented by experts in their fields.
The Success Story of 90 years of Hardmetals
by Dr Henk van der Berg (Kennametal Shared Services GmbH, Germany)
Hardmetal is synonymous with WIDIA in many parts of the world. This talk presents the early developments not only at the German birthplace of Hardmetals, but sets it in perspective with simultaneous developments in other parts of the world as well. Alloys, processes and properties of the early materials compared to todays matured materials will be presented. The advances in the past 90 years will be highlighted with a short outlook of the future of Hardmetals.
Powder Developments as an Essential Contribution to the Hardmetal Success Story
by Dr Tino Säuberlich (H C Starck GmbH, Germany); Dr Gerhard Gille (Previously H C Starck GmbH, Germany); Dr Juliane Meese-Marktscheffel (H C Starck GmbH, Germany)
The success story of hard metals lasting now for 90 years is primarily a consequence of unique and superior combinations of high hardness, stiffness, wear resistance, and moderate toughness and strength. These unique combinations can be achieved by a liquid phase sintered heterogeneous structure of hard WC grains embedded in a Corich binder. During all the 90 years of hard metal production the main measure to expand and further improve the hardness-toughness combinations was to extend the WC grain sizes to the fner but also to the coarser end. This explains the crucial role of WC powder production for the hard metal development and resulted in a close and fruitful cooperation between hard metal and powder producers. Besides the hardness-toughness combinations, other properties and in particular strength and cutting tool edge stability strongly depend on structural defects such as pores and inclusions of impurities or other chemical inhomogeneities. This dependency of strength on defects is found for all hard metals but most pronounced and limiting to performance for submicron and especially for nano-sized hard metals. To use the full potential of fner and fner grain sized hard metals requires therefore a progressive reduction of all kinds of structural defects. This could be achieved by continuously improved and new process technologies of hard metal as well as powder production such solvent extraction, high purity crystallization, inert gas jet milling, advanced milling and granulation, as well as sinter-hip.
This paper gives an overview of historical and current aspects and also some future prospects of powder developments, with special focus on gas-carburized nano WC powder.
Microstructure Engineering to Improve the Performance of Hardmetals
by Prof Dr Z. Zak Fang (University of Utah, United States of America)
The properties of any metallic alloys are dependent on their microstructure. Hardmetals are no exception. However, after 90 years of carbide, hardmetals are considered a mature material in both research and industrial communities. It is thus implied that it is diffcult to improve or change WC-Co in any drastic or fundamental ways. In this presentation, we discuss a few examples in which the performance, and sometimes the basic mechanical properties, of WC-Co materials are improved by designing unique and novel microstructures. These examples demonstrate that although carbide tools that will never wear nor break, do not exist, there are opportunities to improve their performance by understanding the degradation and failure mechanisms and design microstructure to address those specifc mechanisms of degradation. The examples include nano or ultrafne grain cemented tungsten carbide, double cemented tungsten carbide, cellular structured hard material composites, and the functionally graded WC-Co. The design of these different microstructures challenges the conventional debates within this community regarding uniform microstructure versus bi-modal microstructure, fne grain versus coarse grain, and strength versus toughness. This presentation aims to contribute to these debates by sharing lessons learned.
Technology Developments – Milling, spray drying, consolidation, sintering, and Post Treatment
by Dr Ralph Useldinger (CERATIZIT Luxembourg S. à r. l., Luxembourg); Dr Uwe Schleinkofer (CERATIZIT Austria GmbH, Austria)
The manufacturing of hard metals incudes a big variety of processes inﬂuencing the behavior and performance in technical application. Since more than 90 years the processes in this feld were subjected to incremental and disruptive innovations. Global competition, cost reduction, energy effciency, and environmental protection serve recently as important starting points in the production and application of cutting tools and wear parts. In this presentation, we cover the processes focused on powder preparation, powder consolidation, sintering, and post treatment of uncoated and coated products and their inﬂuence on behavior, cost, and product performance. Industrial requirements lead to innovative developments i.e. in the felds of geometric complex pressed to size parts as well as resource friendly hard metal compounds. Based on the actual status referring to these hard metal production processes an outlook will be drawn based on the signifcantly increasing technical demands on hard metal components and the consequences on their manufacturing processes.
Development of wear resistant coatings for cutting tools
by Dr José García; Jeanette Persson; Emmanuelle Göthelid (AB Sandvik Coromant R&D, Sweden)
The tool life of high performance cemented carbide cutting tools can be considerable extended by applying thin wear resistant layers. Chemical vapor deposition (CVD) and physical vapor deposition (PVD) are established industrial techniques for deposition of wear resistant thin layers in cutting tools. There is an extended variety of protective coatings, which properties are tailored for specifc applications. Generally the main goal is to optimize material properties aiming at reducing wear, friction, oxidation and corrosion. Processing parameters will inﬂuence coating adhesion to the substrates, microstructure features such as morphology, texture, residual stresses and layer thickness among others. This presentation offers an overview of selected development in the area, focusing on the historical development of coatings for cutting tools, the present technology and some future trends.
Cemented Carbide as an Important Enabler for Machining Developments
by Prof Dr Dirk Biermann (TU Dortmund University, Institute of Machining Technology, Germany)
Cemented carbide cutting tools are most important for machining operations and their development. During the 90 years of the cemented carbides a lot of improvements could be achieved. Today the market of cutting tools is dominated by a very high number of different cemented carbide grades with different characteristics, which are important for certain applications. In combination with hard coatings it is possible to develop suitable solutions for nearly all machining operations. This paper starts with an overview of important historical aspects of the use of cemented carbide as cutting tool material, it shows the state of the art with selected examples for important felds of application and will also give future prospects related to the development and design of new cemented carbide cutting tools for challenging machining operations.