Widia

Very great hardness would thus be expected in nitrides and carbides in which, starting from the assumption of ionic bonding, tri- and quadrivalent negative ions would be present. In fact the extremely hard substances, such as carborundum SiC as well as AIN, TiN, TiC and WC employed as Widia metal, belong to these groups. 

Figure 17 Examples of different cutting inserts used in cutting industry (Kennametal-Widia GmbH)...

Krupp offered the first cemented carbide (WC-6%Co) at the Leipzig tool fair. The brand name was WIDIA, an abbreviation of Wie Diamant (like diamond in German) and is still known all over the world. 

FIGURE 9.25. Three-chamber vacuum sintering furnace for hardmetal production (Ipsen). By courtesy of WIDIA GmbH., Germany. 

Figure 25. Microstructure (light-optical microscope) of a WC/Co-based hardmetal (WIDIA TTR)...

Figure 26. Microstructure (SEM image) of a cemented carbonitride (WIDIA TTI 25) showing round hard particles with core-rim type structure.

Figure 27. Milling and turning inserts with various coatings. The top coating is TiN (golden yellow), Zr(C, N) (violet) and AI2O3 (black). From WIDIA, Germany.

AI2O3 is often used to provide a ceramic material in contact with the workpiece or to apply several multilayers of the type Al203/TiN. The thicknesses of the sublayers are on the order of about 1 pm and the total layer thickness is about 10-12 pm. Such a structure is shown in Fig. 29 for the WIDIA grade TNI 50. Most of these layers are deposited by CVD. Also a combination of PVD and CVD ( duplex ) techniques was studied and has yielded better performing layers than other titanium nitride and carbonitride coatings [110]. 

F ure 28. Microstructure of a coated WC/Co-based cutting tool for turning steel (WIDIA TN250) where the layer is composed of three sublayers. 

Figure 29. Microstructure of a multilayer-coated steel-turning hardmetal (WIDIA TNI50), with various TiN/Al203 sublayers a TiN and a Ti(C, N) layer.

The author would like to thank Dr. K. Dreyer, WIDIA GesmbH, Essen (Germany) for support with figures and microstructures of tools parts. The help of Mr. W. Prohaska with the preparation of the phase diagram drawings is gratefully acknowledged. 

A soln. of dilorine in CCI4 added to a stirred soln. of 5 -diolestane-3), 19-diol in chloroform containing pyridine, after 15 min. a little isopropyl alcohol added, and the product isolated after an additional 5 min. -> 5 -diolestan-19-ol-3-one. Y almost 100%. F. e., also oxidation to aldehydes, s. J. Widia and A. Zarecki, Tetrah. Let. 1974, 3059. 

WIDIA Magnettechnik, Gesinterte Dauermagnete Ko-erzitund Koerox, d.2000.D.5... 

Coated carbide tools are known to perform better than uncoated carbide tools. Thus commercially available CVD coated carbide tools were used in this investigation. The tools used were flat end mill cutters produced by WIDIA (EM-TiAlN). The tools were coated with TiAlN coating. For each material a new cutter of same specification was used. The details of the end milling cutters are given below ... 

A HMT lathe (NH22) is used for turning EN8 steel of hardness number 190 on the Vicker scale (with a load of 20 kgs. using a pyramidal indentor). The uncoated carbide inserts used are - SPUN 120308, grade P20-P30, normal rake 6 deg., front clearance angle 11 deg., make WIDIA. 

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