Best Practice Guide for Foundry Sector of India BEST PRACTICE GUIDE FOR FOUNDRY SECTOR OF INDIA For the BEE-GEF-World Bank Project FINANCING ENERGYSmith EFFICENCY AT MSMEs [Type the company name] [Pick the date] A joint activity by: Bureau of Energy Efficiency (BEE) & Institute for Industrial Productivity (IIP) Prepared by: MB Associates, UK March 2012 Best Practice Guide for Foundry Sector of India CONTENTS Page No 1.0 Introduction 14 2 Alternatives for Best Technology Selection 16 2.1 Melting Technology 16 2.2 Metal Treatment and Pouring 17 a) Iron Castings 17 b) Steel Castings 19 2.3 Moulding Technology 29 2.4 Core making 30 2.5 Casting Cooling and Separation 33 Exhibit A – Market sector chart – iron foundries – melting Exhibit B – Comparison of arc furnaces with induction furnaces for steel foundries Exhibit C – Product and manufacturing method classification Exhibit D – Best practice guide – melting matrix Exhibit E – Market sector chart – iron foundries – moulding Exhibit F – Best practice guide – moulding matrix Exhibit G – Size suitability chart – coremaking Exhibit H – Typical process flow – coremaking Exhibit I – Best practice guide – coremaking matrix Exhibit J – Best practice guide – casting separation matrix Exhibit K – Best practice guide – casting cooling matrix MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Page No 3.0 Melting 47 3.1 Raw Materials 47 a) Controlling Raw Materials 47 b) Ferrous Scrap 48 c) Ferro-Alloys 51 d) Subsidiary Raw Materials 52 e) Inoculants 58 f) Weighbridge 61 g) Stockyard 61 3.2 Cupola Furnaces 63 a) Introduction 63 b) Conventional Cold Blast Cupola Operation 64 c) Divided Blast Cupola 66 d) Hot Blast Cupola 67 e) Oxygen Enrichment 68 f) Long Campaign Cupolas 70 g) Ancillary Equipment 71 3.3 Coreless Induction Melting Furnaces 74 a) Introduction 74 b) Furnace Operation 76 c) Coreless Furnace Process Control 81 3.4 Channel Induction Furnaces 84 a) Introduction 84 b) Basic Description 84 c) Vertical Channel Furnace 85 d) Drum and Bath Type Furnaces 85 e) Duplexing 86 f) Melting 87 g) Alloying 87 h) Deslagging 87 I) Refractories 88 2 MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Page No 3.5 Electric Arc Furnaces 88 a) Introduction 88 b) Electrical Operation 89 c) Electrode System 90 d) Refractories 91 e) Process 92 f) Production Control 93 g) Direct Current EAF 94 Exhibit L – Approximate composition of the main grades of cast iron scrap Exhibit M – Typical compositions of pig irons Exhibit N – Carburising materials Exhibit O – Alloys for ladle or electric furnace additions Exhibit P – Guide to maintaining quality control in ferrous industries – raw materials for metal production Exhibit Q – Schematic outline of a cupola furnace Exhibit R – Divided blast cupola Exhibit S – How metal temperature can be increased or how coke consumption may be reduced and melting rate increased by divided blast operation Exhibit T – Coreless induction furnace Exhibit U – Stirring action Exhibit V – Vertical channel furnace Exhibit W – Drum type channel furnace Exhibit X – Examples of the electrical currents carried by electrodes at nominal installed furnace power 3 MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Page No 4.0 Metal Treatment and Pouring 110 4.1 Inoculation 110 a) Grey Cast Iron 110 b) Ductile Iron 110 4.2 Secondary Steelmaking Processes 112 a) Converter Process 112 b) Ladle Metallurgy 113 c) Induction Heated Methods 115 4.3 Pouring 115 a) Grey and Ductile Iron 115 b) Steel Alloys 116 Exhibit Y – Secondary Metallurgical Process Methods 4 MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Page No 5.0 Moulding 119 5.1 Moulding Process Options 119 5.2 Sand Properties 120 a) Introduction 120 b) Sand Properties 120 5.3 Clay Bonded Processes 124 a) Greensand 124 b) Clay Binders 125 c) Other Additives 127 d) Water 129 e) Mixing/Mulling 130 f) Mixing Equipment 130 g) Moulding 133 h) Moulding Machines 135 5.4 Chemically Bonded Sand 144 a) Binder Systems 144 b) Acid Set Furan Binders 145 c) Acid Set Phenolic Resoles 149 d) Alkyd Urethane Resin Process 151 e) Ester Hardened Alkaline Phenolic Resins 152 f) Ester Hardened Silicates 155 g) Phenolic Urethane Cold Set 157 h) Cement Sands 160 I) Fluid Sands 160 j) Cold Setting Moulding Production 161 k) Reclamation 163 5.5 Other Moulding Processes 165 a) Shell or Croning Sand 165 b) Lost Foam Process 171 c) Centrifugal (Permanent Mould) 184 d) V-Process 185 5 MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Exhibit Z – Major moulding processes Exhibit AA – Casting process comparison – dimensional tolerances Exhibit AB – Casting process comparison – relative surface finish Exhibit AC – Casting process comparison – tool costs Exhibit AD – Casting process comparison – complexity of design Exhibit AE – Casting process comparison – ease of engineering changes Exhibit AF – Casting process comparison – near net shape capability Exhibit AG – Classification of grain shapes Exhibit AH – Sintering points for silica sand Exhibit AI – Simplified clay structure Exhibit AJ – Montmorillonite Exhibit AK – Kaolinite Exhibit AL – Vertical wheel batch muller Exhibit AM – High speed muller Exhibit AN – Continuous mixer Exhibit AO – Alteration to bulk density of foundry sand with mixing intensity Exhibit AP – Comparison of mixing times Exhibit AQ – Jolt – squeeze method Exhibit AR – Impulse and squeeze compaction operating sequence Exhibit AS – The Seiatsu process sequence Exhibit AT – The Dynapuls operation Exhibit AU – Variable compacting intensity Exhibit AV – Vacuum squeeze moulding Exhibit AW – Hunter machine sequence 6 MB Associates Best Practice Guide for the Foundry Sector of India Exhibit AX – Vertically parted flaskless moulding Exhibit AY – Machine layout Exhibit AZ – Horizontally parted/vertically produced moulding sequence Exhibit BA – Mould blowing mechanism Exhibit BB – Description of binder systems Exhibit BC – Typical addition rates for binders Exhibit BD – Operating sequence of typical shell moulding machine Exhibit BE – Equipment for processing EPS Exhibit BF – Moulding EPS Exhibit BG – The lost foam casting process Exhibit BH – Tolerances of foam patterns Exhibit BI – V-Process manufacturing stages 7 MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Page 6.0 Core making 223 6.1 Binder Systems 223 a) Hot Curing Processes 223 b) Cold Setting Processes 229 c) Vapour Curing Processes 230 6.2 Core making Equipment 256 a) Introduction 256 b) Mixing Equipment for Core making 261 c) Odour Removal 263 Exhibit BJ – Core processes in use Exhibit BK – Application of hot box cores Exhibit BL – Water reaction with MDI Exhibit BM – Components of a typical core machine Exhibit BN – Core removal Exhibit BO – Air impact core machines – sequence of operations Exhibit BP – Gen-Atsu sand compaction method Exhibit BQ – Laempe mixer Exhibit BR – Packed bed scrubber Exhibit BS – Impingement plate scrubber Exhibit BT – Impingement plate tower 8 MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Page No 7.0 Cooling and Separation 277 7.1 Casting Cooling 277 a) In-Mould Cooling 277 b) Casting Cooling Outside the Mould 277 7.2 Casting/Sand Separation 279 a) Rotary Drum 279 b) Vibrating Drum 279 c) Vibratory Shake-Outs 280 7.3 Sand Cooling 281 a) Introduction 281 b) Rotary Cooling Screen 282 c) Fluidised Bed Cooling 283 d) Vertical Tower Cooler 283 e) Cooling Drums 284 f) Bucket Elevators 284 g) Cooling Sand in a Batch Mill Using Vacuum 285 h) Slow Running Conveyor Belts 286 Exhibit BU – Rotary drum Exhibit BV – Vibratory drum Exhibit BW – Relationship between temperature and moisture absorption in air Exhibit BX – Main elements of a rotary cooling screen Exhibit BY – Cooling screen temperature trace Exhibit BZ – Basic elements of a fluid bed cooler Exhibit CA – Vertical tower cooler Exhibit CB – Schematic diagram of a vacuum cooling system for moulding sand Exhibit CC – Pressure v/s temperature Exhibit CD – Vapour pressure curve for water Exhibit CE – Pressure/temperature diagram for water Exhibit CF – Time diagram – moulding sand cooling in a vacuum mixer 9 MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Page No 8.0 Finishing 299 8.1 De-sprueing, Grinding and Fettling Castings 299 a) Feeder Removal 299 b) Dressing of Castings 300 c) Automation of the Fettling Process 306 d) Weld Repair 398 8.2 Cleaning of Castings 309 a) Introduction 309 b) Reasons for Cleaning Castings 309 c) Methods of Cleaning Castings 310 d) Reasons for Shotblasting 311 e) Types of Shotblasting Equipment 312 f) Abrasives Available for Shotblasting 314 8.3 Heat Treatment 318 Exhibit CG – Table machines Exhibit CH – Tumble machines Exhibit CI – Continuous machines Exhibit CJ – Characteristics of principal types of abrasive Exhibit CK – Typical grades of steel and chilled iron abrasives used for cleaning various castings Exhibit CL – Iron – carbon equilibrium diagram 10 MB Associates Best Practice Guide for the Foundry Sector of India CONTENTS (Cont) Page No 9.0 Patternmaking 328 9.1 Introduction 328 9.2 Pattern Construction 329 a) Pictorial Drawings 330 b) Orthographic Projections 330 c) Finding a Joint Line 330 d) Pattern Taper 331 e) Contraction Allowance 332 f) Machining Allowance 332 g) Set-Out 333 9.3 Patterns and Corebox Finishing 333 a) Reasons for Applying Surface Coating to Pattern 334 Equipment 9.4 Materials Used in Patternmaking 335 a) Reasons