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PDF File Generated From OCCASION This publication has been made available to the public on the occasion of the 50th anniversary of the United Nations Industrial Development Organisation. DISCLAIMER This document has been produced without formal United Nations editing. The designations employed and the presentation of the material in this document do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations Industrial Development Organization (UNIDO) concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries, or its economic system or degree of development. Designations such as “developed”, “industrialized” and “developing” are intended for statistical convenience and do not necessarily express a judgment about the stage reached by a particular country or area in the development process. Mention of firm names or commercial products does not constitute an endorsement by UNIDO. FAIR USE POLICY Any part of this publication may be quoted and referenced for educational and research purposes without additional permission from UNIDO. However, those who make use of quoting and referencing this publication are requested to follow the Fair Use Policy of giving due credit to UNIDO. CONTACT Please contact [email protected] for further information concerning UNIDO publications. For more information about UNIDO, please visit us at www.unido.org UNITED NATIONS INDUSTRIAL DEVELOPMENT ORGANIZATION Vienna International Centre, P.O. Box 300, 1400 Vienna, Austria Tel: (+43-1) 26026-0 · www.unido.org · [email protected] Advances in Materials Technology: MONITOR Issu~ Number 12 1988/1 MATERIALS FOR CUTTING TOOLS This publication is distributed free of charge Dear Reader, This is number 12 of UNIDO's state-of-the-art s~ries in the field of aaterials entitled Advances in Materials Technology: Monitor, which is devoted to ..terials for cutting tools. Two professors froa Warwick University in Coventry, United Kingdom, have written the aain article for this issue. In each issue of this series, a selected aaterial or grvup of aaterials is featured and an expert assess•ent aade on the technological trends in those fields. In addition, ot~er relevant inforaation of interest to developing countries is provided. l~ this aanner, over a cycle of several issues, aaterials relevant to developing countries could be covered and a state-of-the-art assessment aade. We invite our readers also to share with us their experiences related to any aspect of production and utilization of aaterials. Due to paucity of space and other reasons, we reserve the right to ~bridge the presentation or not publish them at all. We also would be happy to publish your forthcoming meetings (please see section •Past events and future aeetings•). We would also be grateful to receive your opinion on possible subjects for our forthcoming issues. In this way we expect to have a dial09ue ~ith our readership to establish th~ feedback which will allow us to effectively aonitor the developments in the field and better serve our readers, especially in the developing countries. For the interest of those of our readers who may he unaware UNIDO also publishes two other Monitors: Microelectronics Monitor and Genetic Engineering and Biotechnology Monitor. For those who would like to receive them please write to the Editor, Microelectronics Monitor and Editor, Geneti= Engineering and Biotechnology Monitor. Department of Industrial Promotion, Consultations and Technoloqy - ii - CONTENTS l. REVIEW OF THE MANUFACTURE AND PROPERTIES OF CERAMIC TOOLS - updated especially for this Monitor by E.O. Ezugwu and J. Wallbank . ., 2. BARD-PART MACHINING WITH CERAMIC INSERTS ! "- 3. MACHINING WITH Al203-SiC WHISKER CU'l"l'ING TOOLS I 5 4. HIGH-PURITY POLYCRYSTALLINE DIAMOND TECHNOLOGY 5. R•D RENDS IN DIAMOND TOOLS 22 6. CARBIDES, CERMETS AND LOTS MORE 7. CURRENT AWARENESS 26 Carbides Ceramics Diamonds Firms and Products Market De~elopments 8. PUBLICATIONS 41 9. PAST EVENTS AND FUTURE MEETINGS 4S l. REVIEW OF THE KANl!FACTURE AND PROPERTIES OF Higher cutting speeds now •"~ilable also deac.nd CDAMIC CUTTING TOOLS l!Y E. 0. EZIJCW'J AND higher power .:>tors and conse~uently the adoption of J • VALLl!ANlt nav aaterlals in this .. rket has always relied on ..nufacturers re-equipping the factory. Synopsis 1.2. llanufacturinq route Th• last 15 years ha~• seen aajor advances in tb• development of cera•ic tool .. terials achieving That caraaic tooling has only recently beer. hi9h cuttlng speeds vith long tool lives. These adopted by the ..tal-cutting industry can be development• require rigld ..chine tools vith higher attributed to the failure of the early cera•ic tools power motors and a change in the vay the tool tips by brittle !ractura. Also these early tools failed are used. The ..,jor areas of application of these to find vide acceptance because they had ..ny new tool ..tarials is in the aerospace industries failures as 1 result of improper application, and probably aC1919Vhat lass in the cast iron f iald. unsui~able equipaent or both. The lov fracture .. There ls now an avar-lncraasing nllSlber of grades strength vas directly related to the presence of (and trade aa.. s) aval•abla and this paper ••plains porosity in the pressed composite as a result of th~ the background and devalopsient of the ..tarials. conventional sintering techniques used. The tools produced vith these early pro.:ess routes also had Briefly, the .. tarials ..y be classified as lsr9e grain sizes, and hence were inherently ve1k 1n al-.iaina- or silicon nltrlde-besed and these base tension, impact •nd dyn.. ic loading. Th••• ~sitions than give rise to fa•ilies of ..terials deficiencies restricted the •pplication of the early vith alloying additions. The ..nufac•uring routes cera•ics to the continuous cutting of soft ..terials are discussed as these ha·•e influence on both grain and cast irons at aoderate speeds and feeds in size and porosity of the finished ..terial both of sufficiently rigid ..chines. o.val0011ec~ we.rt 12-C) which influence the behaviour of the .. terials in resulted in higher strength, !llOre unif>r• ,,...} ._.tter use. Finally, the vear of these tools is ••••ined quality tools through an understandi~: nt ~he against the resulting understanding of the importance of aicrost:ucture in con.ro;l i.1g the •icrostructures. aecbanical properties, coupled with 1111provad processing techniques. There are three .. jor l. !nlroduction c1tegories of ceraaic tool .. terials available tod•y: pure oside, •ixed oxide and nitride In ..tal cutting a chip is for ..d by plastic ceraaics. Aluaina (Al 2o11 is predominant in the defor.. tion and fracture of the workpiece aaterial. pure oxide and •ixed oxide cer••ics. While silicon It has been shown by simple co~tinuu• ..chanics [l) ls prado9inant in the nitride ~era•ics. It is that defor.. tion in the region of 200-400 per cent there!ore useful to classify ceraaic tools into is required to for• a continuous chip. •ith cutting alwaina- and Jilicon nitride-based ..terials. s~eds of 100 •/•in defo:aation rates of about 104 sac-l are often observed in this process Alumina-based aaterials leading to high te•peratures and requiring high forces for this to occur. The stresses on the tool These include Al 2o1, Al 2o1 • ZrO", vhen ..chining even soft ..terials such as 70/lO Al o + TiC. Al 0 + TiC • Tih • Zr0 , 2 2 3 2 3 2 brass ..y be as high as l,800 MN'm , .:onsequently A1 2o1 + TiN and the recently developed Al 203 tool aatar1als need to withstand extremely high relnforceci vith SiC whiskers (5). Pure oxide stress at l.-paratures up tv l.O~o·c for high-speed (A1 2o31 ceramic vas first considered for ..chining. ..chining operations in Federal Republic of c.r ..n;· as early as 1905, 25 years before ce... ntad carbides Ceraaics vere introduced in Comatkrci•l vere introduced. This vas a relatively high purity quantities durin·1 the Second World War be.:ause of tool in which pure •lumina was densified in the the sc•r.:ity of tungsten, the basic raw aaterial for presence of grain grovth inhibitors (such as MgO, c ...nted carbide toe.ls. The history of c~ra•ics TiO etc.1. Mixed ceramics vere introduced in the dates as far back as the upper paleolithic ti ..s 1950s as one of a r•n9• of different ..tarials based vben ceraaic tools were used in the fitst simple on consoli~ate alumina in order to ...t the ..chines. 121 There vas no record of the string•~~ ..chanieal property requir... nt1 of ..tal davalop91ent of cera•ic tools after their early use cutting. They .. y be classified i·.no ..u1 bonded until the early part of this certury. and alloy tools. (6) ln ..t1l-bonded ceraaics. aluaina is bonded by one or aore of the transition Ceraaic tool .. taria~• exhibit varf high ..t•ls while tn alloyed tools, various alloying bardness and vear resistance, high resistance to components either result in secondary phases or • plastic defor.. tion, cha•ical stability, ate. They re.. in tn 1olid solution. ~h• .. in &lloying presently constitute about t-5 par cant of the total additions are Zirconia czro21, TiC and TiN. e1tl.. ted indesabl• ln1art .. rkat for ..tal cutting Ill ind are u1ed in the autoeotive industrv Silicon nitride-based aatari~l• predoaln1ntly for high-speed ..chining of grey c••• iron for producing brake druas, brake discs and These vere developed in the late 1970s. There flyvheel1. Caraaic tools are also used for are two to1••· the 04and A': ot.. -St 3N4 is harder high-1peed ..chining of superalloys, hard chill cast than theD -s1 3N4 and both for•• are hexagonal, lron and high-strength steels.
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