Tài liệu Foseco Non-Ferrous Foundryman’s Handbook Episode 11 doc

Foseco Non-Ferrous Foundryman’s Handbook

Foseco Non-Ferrous

Foundryman’s Handbook

Eleventh edition

Revised and edited by

John R. Brown

OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI

Preface

The last edition of the Handbook was published in 1994 and like all the earlier

editions, it aimed to provide a practical reference book for all those involved

in making castings in any of the commonly used alloys by any of the usual

moulding methods. In order to keep the Handbook to a reasonable size, it was

not possible to deal with all the common casting alloys in detail. Since 1994

the technology of casting has continued to develop and has become more

specialised so that it has been decided to publish the 11th edition of the

Handbook in three separate volumes:

Non-ferrous dealing with aluminium, copper and magnesium casting

alloys

Iron dealing with grey, ductile and special purpose cast

irons

Steel dealing with carbon, low alloy and high alloy steels

Certain chapters (with slight modifications) are common to all three

volumes: these chapters include tables and general data, sands and sand

bonding systems, resin bonded sand, sodium silicate bonded sand and

feeding systems. The remaining chapters have been written specifically for

each volume.

The Handbook refers to many Foseco products. Not all of the products are

available in every country and in a few cases, product names may vary.

Users should always contact their local Foseco company to check whether a

particular product or its equivalent is available.

The Foseco logo and all product names appearing in capital letters are

trademarks of the Foseco group of companies, used under licence.

John R. Brown

........................................................................Preface

................................................... Acknowledgements

1 Tables and general data......................................... 1

SI units and their relation to other units................................... 1

SI, metric, non-SI and non-metric conversions........................ 2

Conversion table of stress values............................................ 5

Areas and volumes of circles, spheres, cylinders etc.............. 6

The physical properties of metals............................................ 7

The physical properties of metals (Continued)........................ 8

Densities of casting alloys ....................................................... 9

Approximate bulk densities of common materials ................... 10

Patternmakers contraction allowances................................... 11

Volume shrinkage of principal casting alloys........................... 13

Comparison of sieve sizes....................................................... 14

Calculation of average grain size ............................................ 15

Calculation of AFS grain fineness number.............................. 16

Recommended standard colours for patterns ......................... 17

Dust control in foundries.......................................................... 18

Buoyancy forces on cores ....................................................... 18

Core print support.................................................................... 19

Opening forces on moulds....................................................... 19

Dimensional tolerances and consistency achieved in

castings ................................................................................... 21

...................................... 2 Aluminium casting alloys

.............................................................................. Introduction

Casting alloys.......................................................................... 25

Casting processes................................................................... 39

The effect of alloying elements................................................ 39

Heat treatment of aluminium alloys ......................................... 42

....................................... 3 Melting aluminium alloys

.............................................................................. Introduction

Raw materials.......................................................................... 47

Melting furnaces...................................................................... 47

Corundum growth.................................................................... 54

Choice of melting unit.............................................................. 55

......................................................................4 Fluxes

Application of COVERAL powder fluxes ..................................

Granular COVERAL fluxes...................................................... 61

5 INSURAL refractory for ladles and metal

.....................................................................transport

Ladle liners.............................................................................. 65

6 Treatment of aluminium alloy melts .....................

Hydrogen gas pick-up in aluminium melts ...............................

Degassing aluminium alloys.................................................... 72

Grain refinement of aluminium alloys...................................... 77

Modification of aluminium alloys.............................................. 79

Sodium modification................................................................ 81

Strontium modification............................................................. 82

Permanent modification........................................................... 83

Sand, gravity die and low pressure diecasting........................ 83

Medium silicon alloys, 4 7% Si................................................ 84

Eutectic silicon alloys, 12% Si ................................................. 84

Treatment of hypereutectic Al Si alloys (over 16% Si) ........... 85

Melting and treatment of aluminium magnesium alloys (

4 10% Mg).............................................................................. 86

Special requirements for gravity diecasting............................. 87

Treatment of alloys for pressure diecasting............................. 87

7 Running, gating and feeding aluminium

castings...................................................................... 75

Gating without filters................................................................ 90

Gating with filters..................................................................... 93

Feeding mechanisms in Al alloy and other non- ferrous

castings ................................................................................... 94

Simulation modelling ............................................................... 98

8 Filtration of aluminium alloy castings ..................

SIVEX FC filters....................................................................... 100

Use of filters in conventional running systems ........................ 101

Direct pouring of aluminium alloy castings.............................. 104

KALPUR combined sleeve and SIVEX FC filter for

aluminium castings.................................................................. 105

Direct pouring into metal dies.................................................. 107

9 Pressure diecasting of aluminium alloys .............

................................................................................Die design

Process control........................................................................ 111

Modification of the diecasting process..................................... 113

Applications of diecastings...................................................... 114

The diecasting foundry............................................................ 114

Die coating............................................................................... 116

10 Low pressure and gravity diecasting .................

.......................................................... Low pressure diecasting

Gravity diecasting.................................................................... 124

Die coatings for gravity and low pressure diecasting .............. 127

....................................... 11 Sand casting processes

Green sand.............................................................................. 136

Moulding machines.................................................................. 137

Core assembly sand processes .............................................. 140

The Lost Foam process........................................................... 144

12 Sands and sand bonding systems ......................

Properties of silica sand for foundry use .................................

Typical silica foundry sand properties ..................................... 151

Safe handling of silica sand..................................................... 152

Segregation of sand ................................................................ 153

Measurement of sand properties............................................. 153

Thermal characteristics of silica sand...................................... 153

Zircon, ZrSiO4 ......................................................................... 154

Chromite, FeCr2O4 ................................................................. 156

Olivine, Mg2SiO4..................................................................... 156

Green sand additives............................................................... 157

The green sand system........................................................... 160

Green sand properties............................................................. 163

Control of green sand systems................................................ 164

Sand testing............................................................................. 165

Control graphs......................................................................... 165

Parting agents ......................................................................... 166

Special moulding materials, LUTRON..................................... 166

............................................... 13 Resin bonded sand

......................................................... Chemically bonded sand

Self-hardening process (also known as self-set, no- bake

.......................................................... or cold- setting process)

Testing chemically bonded, self-hardening sands................... 169

Mixers...................................................................................... 171

Sand quality............................................................................. 172

Pattern equipment ................................................................... 172

Curing temperature.................................................................. 173

Design of moulds using self-hardening sand........................... 173

Foundry layout......................................................................... 173

Sand reclamation..................................................................... 175

Typical usage of sand reclamation.......................................... 178

Furanes ................................................................................... 180

Phenolic-isocyanates (phenolic-urethanes)............................. 182

Alkaline phenolic resin, ester hardened................................... 183

Heat triggered processes ........................................................ 185

Gas triggered systems............................................................. 186

The shell or Croning process................................................... 187

Hot-box process ...................................................................... 189

Warm-box process .................................................................. 190

Oil sand ................................................................................... 191

Phenolic-urethane-amine gassed (cold-box) process ............. 193

ECOLOTEC process (alkaline phenolic resin gassed with

CO2)........................................................................................ 195

The SO2 process..................................................................... 196

SO2- cured epoxy resin........................................................... 198

Ester-cured alkaline phenolic system...................................... 198

Review of resin core-making processes.................................. 199

14 Sodium silicate bonded sand ..............................

........................................................................ Sodium silicate

CO2 silicate process ( basic process)..................................... 205

Gassing CO2 cores and moulds.............................................. 207

Improvements to the CO2 silicate process.............................. 208

The CARSIL range of silicate binders ..................................... 209

SOLOSIL ................................................................................. 209

Self-setting sodium silicate processes..................................... 210

Ester silicate process............................................................... 210

Adhesives and sealants........................................................... 215

CORSEAL sealants................................................................. 215

TAK sealant............................................................................. 215

.............................................. 15 Magnesium casting

.......................................................................... Casting alloys

The melting, treatment and casting of magnesium alloys ....... 218

16 Copper and copper alloy castings ......................

The main copper alloys and their applications ........................

Specifications for copper-based alloys.................................... 226

Colour code for ingots ............................................................. 227

Melting copper and copper-based alloys................................. 232

Melting and treatment of high conductivity copper.................. 238

Copper-silver........................................................................... 242

Copper cadmium.................................................................... 243

Copper chromium................................................................... 243

Commercial copper ................................................................. 243

Melting and treatment of brasses, copper zinc alloys............. 244

Melting bronzes and gunmetals............................................... 248

Melting aluminium bronze........................................................ 250

Melting manganese bronze ..................................................... 250

Melting high lead bronze ......................................................... 250

Melting copper nickel alloys.................................................... 251

Filtration of copper-based alloys.............................................. 251

................................................... 17 Feeding systems

........................................................................ Natural feeders

Aided feeders .......................................................................... 253

Feeding systems ..................................................................... 254

The calculation of feeder dimensions...................................... 257

Steel, malleable iron, white irons, light alloys and copper￾based alloy castings................................................................ 262

Grey and ductile irons.............................................................. 266

Introduction.............................................................................. 268

Range of feeder products........................................................ 269

Breaker cores.......................................................................... 279

The application of feeder sleeves............................................ 280

Williams Cores......................................................................... 283

FERRUX anti-piping compounds for iron and steel

castings ................................................................................... 284

Metal-producing top surface covers ........................................ 285

FEEDOL anti-piping compounds for all non-ferrous alloys...... 286

Aids ot the calculation of FEEDER requirements.................... 286

Nomograms............................................................................. 287

FEEDERCALC ........................................................................ 287

Calculating feeder sizes for aluminium alloy castings ............. 288

........................................................................... Index

Acknowledgements

The following Organisations have generously permitted the use of their

material in the Handbook:

The American Foundrymen’s Society, Inc., 505 State Street, Des Plaines,

Illinois 60016-8399, USA.

The Association of Light Alloy Founders (ALARS), Broadway House,

Calthorpe Road, Five Ways, Birmingham, B15 1TN.

BSI, Extracts from British Standards are reproduced with the permission of

British Standards Institution. Complete copies can be obtained by post

from Customer Services, BSI, 389 Chiswick High Road, London W4

4AL.

Buhler UK Ltd, 19 Station Road, New Barnet, Herts, EN5 1NN.

Butterworth-Heinemann, Linacre House, Jordan Hill, Oxford OX2 8DP.

The Castings Development Centre (incorporating BCIRA), Bordesley Hall,

The Holloway, Alvechurch, Birmingham, B48 7QB.

The Castings Development Centre (incorporating Steel Castings Research &

Trade Association), 7 East Bank Road, Sheffield, S2 3PT.

Chem-Trend (UK) Ltd, Bromley Street, Lye, Stourbridge, West Midlands

DY9 8HY.

Copper Development Association, Verulam Industrial Estate, 224, London

Road, St. Albans, Herts, AL1 1AQ.

Foundry International, DMG Business Media Ltd, Queensway House, 2

Queensway, Redhill, Surrey, RH1 1QS.

Foundry Management & Technology, 1100 Superior Avenue, Cleveland, OH

44114, USA.

Foundry & Technical Liaison Ltd, 6-11 Riley Street, Willenhall, West

Midlands, WV13 1RH.

The Institute of British Foundrymen, Bordesley Hall, The Holloway,

Alvechurch, Birmingham,

B48 7QA.

International Magnesium Association, 1303 Vincent Place, Suite One,

McLean, Virginia 22101, USA.

OEA (Organisation of European Aluminium Refiners and Remelters,

Broadway House, Calthorpe Road, Five Ways, Birmingham, B15 1TN.

Ramsell Furnaces Ltd, Wassage Way, Hampton Lovett Industrial Estate,

Droitwich, Worcestershire, WR9 0NX.

Striko UK Ltd, Newcastle Street, Stone, Staffordshire, ST15 8JT.

The author gratefully acknowledges the help received from many individ￾uals, in particular from colleagues at Foseco.

Acknowledgements xiii

All statements, information and data contained herein are published as

a guide and although believed to be accurate and reliable (having

regard to the manufacturer’s practical experience) neither the manu￾facturer, licensor, seller nor publisher represents or warrants, expressly

or implied:

1 Their accuracy/reliability

2 The use of the product(s) will not infringe third party rights

3 No further safety measures are required to meet local

legislation.

The seller is not authorised to make representations nor contract on

behalf of the manufacturer/licensor. All sales by the manufacturer/

seller are based on their respective conditions of sale available on

request.

Chapter 1

Tables and general data

SI units and their relation to other units

The International System of Units (SI System) is based on six primary

units:

Quantity Unit Symbol

length metre m

mass kilogram kg

time second s

electric current ampere A

temperature degree Kelvin K

luminous intensity candela cd

Multiples

SI prefixes are used to indicate multiples and submultiples such as 106 or

10–3

Prefix Symbol Prefix Symbol

10 deca da 10–1 deci d

102 hecto h 10–2 centi c

103 kilo k 10–3 milli m

106 mega M 10–6 micro

109 giga G 10–9 nano n

1012 tera T 10–12 pico p

Example: One millionth of a metre is expressed as one micrometre, 1m.

2 Foseco Non-Ferrous Foundryman’s Handbook

Derived units

The most important derived units for the foundryman are:

Quantity Unit Symbol

Force newton N (kg m/s2)

Pressure, stress newton per square metre or pascal N/m2 (Pa)

Work, energy joule J (Nm)

Power, heat flow rate watt, joule per second W (J/s)

Temperature degree Celsius °C

Heat flow rate watt per square metre W/m2

Thermal conductivity watt per metre degree W/m K

Specific heat capacity joule per kilogram degree J/kg K

Specific latent heat joule per kilogram J/kg

SI, metric, non-SI and non-metric conversions

Length:

1 in = 25.4 mm

1 ft = 0.3048 m

1 m = 1.09361 yd

1 km = 1093.61 yd = 0.621371 miles

1 mile = 1.60934 km = 1760 yd

1 yd = 0.9144 m

Area:

1 in2 = 654.16 mm2

1 ft2 = 0.092903 m2

1 m2 = 1.19599 yd2 = 10.76391 ft2

1 mm2 = 0.00155 in2

1 yd2 = 0.836127 m2

1 acre = 4840 yd2 = 4046.86 m2 = 0.404686 m2 hectare

1 hectare = 2.47105 acre = 10 000 m2

Volume:

1 cm3 = 0.061024 in3

1 dm3 = 1 l (litre) = 0.035315 ft3

1 ft3 = 0.028317 m3 = 6.22883 gal (imp)

1 gal (imp) = 4.54609 l (litre)

1 in3 = 16.3871 cm3

1 l (litre) = 1 dm3 = 0.001 m3 = 0.21997 gal (imp)

1 m3 = 1.30795 yd3 = 35.31467 ft3