Materials for automobile bodies

Materials for Automobile Bodies Geoffrey Davies AMSTERDAM • BOSTON • HEIDELBERG • LONDON NEW YORK • OXFORD • PARIS • SAN DIEGO SAN FRANCISCO • SINGAPORE • SYDNEY • TOKYO Butterworth-Heinemann is an imprint of Elsevier Tai ngay!!! Ban co the xoa dong chu nay!!! Butterworth-Heinemann is an imprint of Elsevier The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK 225 Wyman Street, Waltham, MA 02451, USA First edition 2012 Copyright Ó 2012 Elsevier Ltd All rights reserved No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, mechanical, photocopying, recording or otherwise without the prior written permission of the publisher Permissions may be sought directly from Elsevier’s Science & Technology Rights Department in Oxford, UK: phone (+44) (0) 1865 843830; fax (+44) (0) 1865 853333; email: permissions@elsevier.com Alternatively you can submit your request online by visiting the Elsevier web site at http://elsevier.com/locate/permissions, and selecting Obtaining permission to use Elsevier material Notice No responsibility is assumed by the publisher for any injury and/or damage to persons or property as a matter of products liability, negligence or otherwise, or from any use or operation of any methods, products, instructions or ideas contained in the material herein Because of rapid advances in the medical sciences, in particular, independent verification of diagnoses and drug dosages should be made British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library Library of Congress Cataloging-in-Publication Data A catalog record for this book is availabe from the Library of Congress ISBN: 978-0-08-096979-4 For information on all Butterworth-Heinemann publications visit our web site at books.elsevier.com Printed and bound in Great Britain 12 13 14 15 16 10 Contents Acknowledgements xi CHAPTER Introduction 1.1 1.2 1.3 1.4 1.5 Introduction Overview of content Materials overview General format of presentation Introduction to body architecture and terminology References CHAPTER Design and material utilization 2.1 2.2 2.3 2.4 2.5 2.6 2.7 Objective Content Introduction Historical perspective and evolving materials technology 2.2.1 Body zones and terminology 2.2.2 Distinction between body-on-chassis and unitary architecture 2.2.3 Early materials and subsequent changes Finite element analysis 2.3.1 Materials for Autobodies One manufacturer’s approach to current design 2.4.1 Product requirements 2.4.2 Structural dynamics 2.4.3 Design for static stiffness 2.4.4 Crashworthiness 2.4.5 Weight efficiency Panel dent resistance and stiffness testing Fatigue 2.6.1 Designing against fatigue Alternative body architecture 2.7.1 The unitary aluminum body 2.7.2 The pressed spaceframe (or base unit) concept e steel 2.7.3 Pressed aluminum spaceframes and associated designs 2.7.4 The ASF aluminum spaceframe utilizing castings and profiles 2.7.5 Examples of hybrid material designs 2.7.6 Designs based on carbon fiber or CFRP 2.7.7 Magnesium 10 13 15 17 18 18 18 19 20 20 20 28 28 33 33 33 34 35 36 42 44 46 48 48 49 53 56 62 64 74 v vi Contents 2.8 Integration of materials into designs 2.8.1 General 2.8.2 Other materials used in body design 2.9 Engineering requirements for plastic and composite components 2.10 Cost analysis Learning points References 74 74 75 84 85 90 90 CHAPTER Materials for consideration and use in automotive body structures 93 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Objective Content Introduction Material candidates and selection criteria 3.2.1 Consistency: a prime requirement Steel 3.3.1 Steel reduction and finishing processes 3.3.2 Surface topography 3.3.3 Effects in processing 3.3.4 Higher strength steels Aluminum 3.4.1 Production process 3.4.2 Alloys for use in body structures Magnesium Polymers and composites 3.6.1 Introduction 3.6.2 Thermoplastics 3.6.3 Thermosets 3.6.4 Polymer and composite processing 3.6.5 Advanced composites for competition cars Repair Learning points References CHAPTER The role of demonstration, concept and competition cars Objective Content 4.1 Introduction 4.2 The ECV and ASVT 4.3 Collaborative development programs 4.3.1 ULSAB and ULSAB 40 4.3.2 FreedomCAR program 94 94 94 98 100 101 103 111 117 117 128 128 129 132 133 133 133 134 135 137 139 142 143 145 146 146 146 147 153 153 155 Contents 4.4 4.5 4.6 4.7 4.3.3 FutureSteelVehicle program 4.3.4 SuperLIGHT-CAR project 4.3.5 RWTH Aachen University FRP reinforcement program Concept cars Competition cars 4.5.1 Introduction 4.5.2 F1 car structures d why composites? 4.5.3 History 4.5.4 Extent of use 4.5.5 Duty d the survival cell structure 4.5.6 Rule conformity and weight 4.5.7 Structural efficiency 4.5.8 F1 d A good match for composites 4.5.9 Design 4.5.10 Chassis loading 4.5.11 Analysis 4.5.12 Materials database 4.5.13 Testing 4.5.14 Survival cell proving 4.5.15 Survival cell crush and penetration 4.5.16 Survival cell impact 4.5.17 Impact absorber design 4.5.18 Construction 4.5.19 Tooling 4.5.20 Materials Rally cars Hypercars Learning points References CHAPTER Component manufacture Objective Content 5.1 Steel formability 5.1.1 Sheet metal pressworking 5.1.2 Sheet properties and test procedures 5.1.3 Effect of surface topography 5.1.4 Effect of zinc coatings 5.1.5 Tooling materials 5.1.6 Hydroforming 5.2 Aluminum formability 5.2.1 Simultaneous engineering approach to design with aluminum 5.2.2 Superplastic forming 157 161 162 162 171 171 173 173 174 174 175 177 177 178 179 180 181 182 182 182 183 184 185 185 185 186 187 189 190 193 194 194 194 194 198 203 205 205 208 215 216 225 vii viii Contents 5.3 Manufacture of components in magnesium 5.4 Production of polymer parts 5.4.1 CFRP for EV and the future Learning points References 228 231 233 237 238 CHAPTER Component assembly: materials joining technology 241 Objective Content Introduction Welding 6.2.1 Resistance welding 6.2.2 Single-sided spot welding 6.2.3 Fusion welding 6.2.4 Laser welding 6.2.5 Friction stir welding Adhesive bonding Weldbonding Mechanical fastening Learning points References 241 241 242 242 242 253 253 255 258 260 263 263 265 266 6.1 6.2 6.3 6.4 6.5 CHAPTER Corrosion and protection of the automotive structure 7.1 7.2 7.3 7.4 Objective Content Introduction Relevant corrosion processes 7.2.1 Corrosion of aluminum and other non-ferrous body materials 7.2.2 Mechanism of paint degradation Effective design principles 7.3.1 Styling 7.3.2 Subassemblies 7.3.3 Panels Materials used for protection of the body structure 7.4.1 Zinc-coated steels e types and use for automotive construction 7.4.2 Painting of the automotive body structure 7.4.3 Environmental improvements in the automotive paint process 7.4.4 Supplementary protective systems 269 270 270 270 271 273 274 276 276 277 277 278 278 289 292 293 Contents 7.5 Empirical vehicle and laboratory comparisons 7.5.1 Vehicle assessments 7.5.2 Laboratory tests 7.6 Introduction to electrochemical methods Learning points References CHAPTER Environmental and safety considerations 8.1 8.2 8.3 8.4 8.5 8.6 Objective Content Introduction Effect of body mass and emissions control Life-cycle analysis Recycling and ELV considerations 8.4.1 The European recycling program 8.4.2 The manufacturer’s policy 8.4.3 Progress worldwide Hygiene 8.5.1 Heavy metal restrictions BIW design for safety 8.6.1 Euro NCAP frontal impact test 8.6.2 Euro NCAP car-to-car side impact test 8.6.3 Euro NCAP side-impact pole test 8.6.4 Euro NCAP pedestrian protection tests 8.6.5 Improving safety performance 8.6.6 Influence of materials 8.6.7 Formula safety regulations Learning points References CHAPTER Future trends in automotive body materials 9.1 9.2 9.3 9.4 Objective Content Introduction Geographic aspects 9.2.1 Current utilization and vehicle demographics 9.2.2 The influence of geography 9.2.3 Geographic development of the industry 9.2.4 The Japanese influence Quantitative assessment Factors influencing material change in the future 9.4.1 Influence of environmental controls 9.4.2 Emissions control and fuel systems 295 295 295 297 304 306 309 309 310 310 311 317 325 325 331 335 337 338 339 339 342 343 344 345 347 351 354 355 357 358 358 358 360 360 361 363 365 370 370 371 371 ix x Contents 9.4.3 Actual BIW material effects 9.4.4 Recycling and ELV legislation 9.4.5 Effects of future design and engineering trends 9.4.6 Advances in manufacturing technology 9.4.7 Improvements in materials specification e trends and requirements 9.5 Combined effect of factors on materials utilization within ‘expected’ and ‘accelerated’ timescales 9.5.1 Possible consequences regarding BIW materials Learning points References Index 373 375 376 379 381 387 391 394 395 397 CHAPTER Introduction CHAPTER OUTLINE 1.1 Introduction 1.2 Overview of content 1.3 Materials overview 1.4 General format of presentation 10 1.5 Introduction to body architecture and terminology 13 References 15 1.1 INTRODUCTION The core content of this edition is essentially the same as the first, but the opportunity has now been taken to update the coverage of both materials and associated manufacturing advances and generally report on progress made during the last decade The latest legislative and environmental requirements are highlighted and the response of the industry in terms of design and processing are outlined These include the progress made with regard to higher strength steels, the application of composites, aluminum and other lightweight materials Advances in processing include the automation of composite outer panel production to a mass production stage, essential if composites are to reach volume models, and the increasing use of lasers in joining, which has been enabled by the increasing versatility of beam technology offered by innovative power sources and transmission modes, such as YAG systems The emergence of electrical drive systems and their possible effects on body-in-white (BIW) design and materials choice is also considered, although it may be at least a decade before electric vehicle (EV) systems in various guises have a real presence in the market In the meantime the opportunity exists for the full potential of alternative steels and lightweight materials being developed through current programs to be realized Significant additions to relevant chapters have been made on subjects such as the development of lightweight body materials in North America and lessons learned from the Far East with regard to the implementation of new steel grades In particular, the contribution from the FreedomCAR Automotive Lightweighting Materials program, sponsored by the US Department of Energy, is discussed This program illustrates the considerable investment in terms of resources and efforts being made into the research and development of lightweight materials A major thrust is being made there to reduce the cost of carbon fiber, so that it becomes Materials for Automobile Bodies DOI: 10.1016/B978-0-08-096979-4.00001-3 Copyright Ó 2012 Elsevier Ltd All rights reserved CHAPTER Introduction a competitive option as a material choice for body structure, and practical recycling solutions are being explored The increased application of non-ferrous body content is being studied, especially with regard to magnesium The EV influenced ‘Future Steel Vehicle’ project is also outlined; it looks at possible structures for small and larger cars from hybrid through to fuel cell modes and considers the modifications necessary for battery and cell stacks The importance of this work is its emphasis on volume production and the pragmatic changes required in order for newer materials to be handled in volume, and, thus, achieve worthwhile reductions in greenhouse and other harmful emissions The opportunity is also taken to update readers on the latest targets for emissions, recycling and end-of-life vehicle (ELV) legislation and the recent progress that has been made by manufacturers in addressing them A major objective for BIW development remains its contribution to emissions control through weight reduction, which is achieved by design and materials choice, and complements the work being carried out on alternative power modes Significant reductions have been achieved in current structures, but further reductions will be necessary to offset the heavier batteries or cell stacks of future designs Steady progress is reported in the use of hydrogen, used either as a replacement fuel in conventional engines or within fuel cells, together with the different types of ‘electromobility’ referred to above Events in the last decade have underlined the critical status of oil supplies The strategic importance of oil has been highlighted by recent events in the Middle East, while in the Gulf of Mexico hurricane damage to significant oil installations and has further heightened our awareness of oil dependence Some reports suggest that existing reserves of oil could run out in 10 years, although 40 years is generally thought to be more realistic Other events have emphasized the danger to the environment by mismanagement of these oil resources The interest in alternative fuels is, therefore, intense Hybrid electric vehicles (HEV) now have plug-in derivatives (PHEV); battery electric vehicles (BEV) have been developed as city cars, while small internal combustion engines (ICE) supplement electrical systems in extended range vehicles (EREV) Fuel cell systems (FCEV) are now undergoing extended fleet trials Serious programs are working on the provision of a universal infrastructure for the supply of hydrogen and plug-in fast-recharging stations for next generation electric vehicles The effects of these systems and the differences in material requirements and architecture compared with ICE-propelled vehicles are considered The current range of steels will continue to be used in the medium term, as safety issues are addressed with increasingly sophisticated front, side and rear end designs, together with aluminum and magnesium to maximize weight reduction The development of plastics and composites in body design is further prompted by their good performance in pedestrian impact situations, and this is driving the search for effective recycling solutions for these materials The basic format and content of the book still stands as before, as does the sequence of the chapters, which offers the most logical form of presentation It is Index Terms Links Ingot cast steel See Steel condition Injection molding 135 Insulating materials (against bi-metallic corrosion) 272 Internal combustion engines (ICE) 68 International Body Engineering Conference (IBEC) 75 International Dismantling Information System (IDIS) International Iron and Steel Institute (IISI) 329 331 317 Interstitial free (IF) forming and high-strength steel See Steel types Intrusion rails 347 Isotropic steels See Steel types IStream concept 168 J Jaguar CX75 169 Jaguar XJ 220 151 Jaguar XJ X351 62f 228 163 Japanese Automobile Manufacturers Association (JAMA) Joining methods 336 140 K Kurtosis 112 L “L” factor 38 This page has been reformatted by Knovel to provide easier navigation Index Terms Land Rover models Links 23 Defender 23 Freelander 23 Laser welding aluminum 256 and brazing systems 380 CO2 and YAG processes 256 joints 20 steel 256 Lasertex 113 Lay-up technology 138 Life-cycle analysis (LCA) 310 LifeDrive concept 69 advantages of 73 317 Lightweight design for electric vehicles Lotus Elise punt design Lotus Engineering 69 53 168 Lotus Versatile Vehicle Architecture (VVA) concept 390 Low cost tooling 226 Low cycle fatigue 44 Lubricant retention 112 Lubrication systems electrostatic 194 pre-applied 150 spray applied 196 Lubricity 194 201 Luders bands See also Stretcher-strain marks aluminum This page has been reformatted by Knovel to provide easier navigation Index Terms Links Luders bands (Cont.) type A 218 type B 218 steel 110 Ludke, Bruno 33 M Magnesium alloys 132 components 228 Fiat cast bulkhead crossmember 228 Main draw die 74 194 Martensitic steels See Steel, grades Mass specific energy absorption 350 McClaren MP4/1 Formula car 64 McLaren F1 137 McLaren MP4-12C construction 67f McLaren Technology Centre Mechanical fastening 64 263 Mechanical properties percentage elongation 198 ultimate tensile stress 198 yield stress 111 Megacity Vehicle (MCV) 71 Metal inert gas (MIG) welding 49 MG EX-E 151 Mill finish 129 Mitsubishi Paquera 23 Morris Oxford 20 218 218 163 Multiphase steels See Steel types This page has been reformatted by Knovel to provide easier navigation Index Terms Links N N value (work-hardening index) 200 New Car Assessment Programs (NCAP) 361 ANCAP (Australia) 339 Euro NCAP (Europe) 339 NCAP (US) 339 Niche cars 54 Noise vibration and harshness (NVH) 33 Nomex 172 Nondestructive testing (NDT) 250 Noryl GTX 232 371 O Oil-canning 42 “One-step” forming solutions 202 “Orange-peel” effect 108 Organization of the Petroleum Exporting Countries (OPEC) oil prices 311 Original equipment manufacturers (OEMs) Overcrowning 336 49 Overstoving 277 Ozone 311 P Paint disbonding 275f See also Saponification Paint priming processes Rotadip 290 Slipperdip 290 This page has been reformatted by Knovel to provide easier navigation Index Terms Links Painting process, application anti-chip protection 292 base coat 292 clear coat 292 electroprimer 290 pretreatment 289 surfacer 291 Panel draw beads 221 Panel locking beads 221 Panel types external “skin” panels 20 structural 20 Partnership for a New Generation of Vehicles (PNGV) 155 Peak count 203 Phosphophyllite 289 Physical vapor deposition (PVD) coatings 287 Pickling 100 Pierce Arrow 20 Piercing operation 221 Pimpling 194 Pitting corrosion 273 Plastics 48 205 74 See also Polymers anisotropy See Drawability index deformation recycling 42 335 Plug-in hybrid electric vehicles (PHEVs) Polymeric materials 371 Polymers See also Thermoplastics, amorphous; Thermosets This page has been reformatted by Knovel to provide easier navigation Index Terms Links Polymers (Cont.) identification techniques 376 parts, production of 231 Polyurethanes RRIM 232f 53 149 Pontiac Fiero 151 152f Pourbaix diagrams 298 299f Pre-applied lubricants 194 Preferential dissolution 278 Preimpregnated reinforcement 138 Pre-painted steel 390 Press lubricant, 10005#t0010 Press tooling development stages buy-off 197 try-out 201 Pressed steel base unit 49 Pressed Steel Company 20 Pressure die casting 228 Pressworking operations main form operations 195f piercing 194 restriking 206 trimming 194 “Prestal” superplastic Zn–Al alloy Process chain 227f 228 Projection welding 243 Proof stress (% PS) 111 Punt-type structure 53 98 Purchasing procedure “specification buying,” 197 This page has been reformatted by Knovel to provide easier navigation Index Terms Links R r value See Drawability index Rally cars 186 Rapid prototyping 226 Reinforced reaction injection molding (RRIM) 53 See also Thermosets, technology polyurethane Renault 53 149 168 Clio 232 Espace 278 Megane, Front Fender 232 Renewable material sources 358 REPAIR 139 Re-phosphorized steel See Steel types Re-polymerized nylon Resin transfer molding (RTM) 335 66 235 See also Thermosets, technology Resistance welding 242 aluminum 251 electrode life, factors influencing 247 high-strength steels 250 spot-welding of aluminum 243 Ford P2000 structure 252f surface resistance 252 stainless steel 251 weldability 245 weld testing 249 Restrike operation 194 Retained austenite 118t Rimming steel See Steel types This page has been reformatted by Knovel to provide easier navigation Index Terms Links Rocky Mountain Institute (RMI) “Hypercar” design concept Rolls-Royce Silver Spirit 187 188f 278 Rover Metros 53 Rover P4, P6, and SD1 49 RWTH aachen university FRP reinforcement program 162 S Safety engineering 339 Sandwich material aluminum 74 83 steels 74 80 Saponification 274 Saturated calomel electrode (SCE), measurement on IZ coating 285 Scanning Kelvinprobe vibrating probe Technique (SKTP) 303 Scanning reference electrode test (SRET) 301 Scanning vibrating electrode test (SVET) 301 Seam welding 247 See also Resistance welding Self piercing rivets 264 264f Sendzimir galvanizing line 283 284f Sheet molding compound (SMC) 231 Shredder residues 330 Side impact beams See Intrusion rails Simultaneous engineering approach 216 Skew 112 Skin panel material selection 149t 150t This page has been reformatted by Knovel to provide easier navigation Index Terms Links Skin passing 110 See also Temper rolling Slumping 219 Smart Micro Compact Car 166 Solvent resistance 85 ® SP resin infusion technology (SPRINT ) material 138 Spaceframe 25 aluminum e ASF 56 aluminum-pressed 53 pressed steel 49 stainless steel 89 Spot clinching 265 Spot welding 243 Springback 202 265f Stainless steel austenitic 127 ferritic 127 stillages 196 Steel grades 74 Steel condition annealed last 108 ingot cast rimming steel 104 stabilized/aluminum killed steel 104 stickers 114 temper rolled/skin passed 108 110 110 Steel surface texture deterministic 114 electro-discharge textured (EDT) 113 electron beam textured (EBT) 114 This page has been reformatted by Knovel to provide easier navigation Index Terms Links Steel surface texture (Cont.) laser textured (Lasertex) 113 Mirror Finish 113 shot blasted 113 Sibertex 114 stochastic 114 115f Steel types bake hardening 119t complex phase or multiphase 119t dual-phase 125 forming grades 96t high-strength grades 117 high-strength low-alloy (HSLA) 118t hot band 104 “IF” high-strength steel 119t interstitial free “IF,” 103 isotropic 118t martensitic 119t rephosphorized 118t 119t TRIP steel 118t 119t ultra high strength steel 118 Stern–Geary equation Stiffness 108 300 42 Strain ageing 110 Strain analysis 201 Strain rate effects 110 Stress corrosion cracking 274 Stress–strain curves aluminum 216f steel 199f Stretch formability 216f 200 This page has been reformatted by Knovel to provide easier navigation Index Terms Stretcher-strain marks Links 49 104 108 See also Luders bands Stretching operations 194 Structural adhesives 42 Structural dynamics 33 SuperLIGHT-CAR 161 Superplastic forming (SPF) 225 Supplementary protective systems 293 261 Surface roughness (Ra) centre-line-average (CLA) peak density 112f 112 Surfacer paint coat See Painting process T T45 186 Tafel slopes 300 Tailor welded blanks (TWB) 80 Tata Novo 365 Temper rolling 111 Tesla Roadster 66 Test methods biaxial bulging 198 ultimate tensile test 198 Thermomechanically affected zone (TMAZ) 258 Thermoplastics amorphous acrylonitrile butadiene styrene (ABS) 133 polyphenylene (PPO) 133 polycarbonate (PC) 133 crystalline polyamides, nylon (PA) 134 This page has been reformatted by Knovel to provide easier navigation 129 Index Terms Links Thermoplastics (Cont.) polyethylene (PE) 134 polypropylene (PP) 134 technology glass mat thermoplastic (GMT) compression molding Thermosets 135 134 technology reaction injection molding (RIM) 136 230f resin transfer molding (RTM) 136 231f Thickness tolerance 197 Threshold limit values (TLVs) 337 235 Throwing power electrogalvanizing 278 electropriming 290 Thyssen Krupp Stahl (TKS) TMS 1200 348 TiAl6V4 F89 (titanium alloy) 96t Tooling materials air-hardening 207t cast iron flame hardening 206 main form 206 chrome plating of 206 cutting 206 oil-hardening 207t trimming 222 water hardening 206 207t Topography See also Surface roughness Torsional stiffness Total ownership costs Touching surfaces 34 148f 277 This page has been reformatted by Knovel to provide easier navigation Index Terms Toyota Prius Links 315 Transformation induced plasticity (TRIP) steel Triaxis press 124 194 Tribology surface topography effects 111 tribosystems 205 Tricationic phosphate 289 Trim attachment precautions 276 Trimming operation 222 Tube hydroforming See Hydroforming Tulip concept car 232f Twill weave carbon fiber 138 Twinning induced plasticity (TWIP) steel 124 348 153 345 385 U Ultra high strength steel (UHSS) See Steel types UltraLight Steel Auto Body (ULSAB) program See also Development Programs UltraLight Steel Auto Body e Advanced Vehicle Concepts (ULSAB-AVC) program 376 UltraLight Steel Auto Closure (ULSAC) project 153 Ultraviolet (UV) resistance Underbody seam sealing 85 293 Undersealing bitumastic formulations 293 cellular PVC 293 Uni-axial straining 198 Uni-axial tensile test 198 Unitary aluminum body 48 This page has been reformatted by Knovel to provide easier navigation Index Terms Links Unitary body design 22f US New Car Assessment Program (NCAP) 339 USINOR, Usibor 1500 349 28 V Vacuum degassing rig Versatile vehicle architecture (VVA) 103 105f 53 170 Volatile organic compounds (VOC) emissions 314 Volvo Safety Concept Car 163 W Walking beam transfer system 194 Waviness 114 Wax injectants 277 duplex zinc coated steel (e.g Durasteel/Bonazinc) 287 electrogalvanized 287 galvanneal (or IZ) 285 Weld time 245 Weldability lobe See Resistance welding Weldbonding 263 Welding 242 friction stir welding 258 fusion welding 253 laser welding 255 resistance welding 242 aluminum 251 electrode life, factors influencing 247 high-strength steels 250 stainless steel 251 This page has been reformatted by Knovel to provide easier navigation Index Terms Links Welding (Cont.) weld testing 249 weldability 245 single-sided spot welding Williams GP Racing Work-hardening, index n Wrinkling 253 175f 200 49 Y Yield stress 111 Yttrium aluminum garnet (YAG) 380 Z Zinc coated steel electrogalvanized 287 galvanneal 285 Zirconium fluoride 290 Zirconium–titanium formulations 290 This page has been reformatted by Knovel to provide easier navigation