Reference Document on Best Available Techniques in the

13,5
MB Smitheries and Foundries Industry (adopted July 2004)

397
stron

6068
ID JRC-IPTS Instituto de Prospectiva Tecnológica (IPTS)

2005
rok

EXECUTIVE SUMMARYI

PREFACE.XIII

SCOPE .XXXI

1 GENERAL INFORMATION ON FOUNDRIES 1

1.1 Sector overview. 1

1.1.1 Foundry industry. 1

1.1.2 Foundry markets . 8

1.1.3 Foundry types . 10

1.2 Environmental issues . 11

1.2.1 Air 11

1.2.2 Residues. 11

1.2.3 Energy 11

1.2.4 Water . 11

2 APPLIED PROCESSES AND TECHNIQUES IN FOUNDRIES. 13

2.1 Overview. 13

2.1.1 The foundry process 13

2.1.2 Iron casting . 15

2.1.3 Steel casting 17

2.1.4 Aluminium casting 19

2.1.5 Magnesium casting . 19

2.1.6 Copper casting 20

2.1.7 Zinc casting. 21

2.1.8 Lead casting 21

2.1.9 Casting of superalloys. 21

2.2 Pattern making . 22

2.2.1 General pattern making. 22

2.2.2 Rapid prototyping (RP). 23

2.3 Raw materials and raw material handling 25

2.4 Melting and metal treatment 28

2.4.1 Cupola furnaces 29

2.4.1.1 Cold blast cupola furnace 29

2.4.1.1.1 Description 29

2.4.1.1.2 Maintenance 30

2.4.1.1.3 Advantages: 30

2.4.1.1.4 Disadvantages: 30

2.4.1.2 Hot blast cupola furnace 30

2.4.1.2.1 Description 30

2.4.1.2.2 Advantages: 32

2.4.1.2.3 Disadvantages: 32

2.4.1.3 Long campaign cupola 32

2.4.1.4 Nature of atmospheric emissions 33

2.4.2 Electric arc furnace (EAF) 34

2.4.2.1 Description 34

2.4.2.2 Melting and refining with the acidic lined EAF 35

2.4.2.3 Melting and refining with the basic lined EAF . 35

2.4.2.4 Nature of atmospheric emissions 35

2.4.3 Induction furnace (IF) . 36

2.4.3.1 Coreless induction furnace 36

2.4.3.1.1 Description 36

2.4.3.1.2 Melting practice 38

2.4.3.1.3 Advantages: 39

2.4.3.1.4 Disadvantages: 39

2.4.3.2 Channel induction furnace 40

2.4.3.2.1 Description 40

2.4.3.2.2 Advantages: 41

xviii Smitheries and Foundries Industry

2.4.3.2.3 Disadvantages: 41

2.4.3.3 Nature of emissions .41

2.4.4 Radiant-roof furnace (resistance heated).42

2.4.5 Rotary furnace .43

2.4.5.1 Description.43

2.4.5.2 Melting practice .43

2.4.5.3 Metallurgy .43

2.4.5.4 Application 44

2.4.5.5 Advantages: .44

2.4.5.6 Disadvantages:.44

2.4.6 Hearth type furnace .44

2.4.7 Shaft furnace .45

2.4.7.1 Description.45

2.4.7.2 Advantages: .46

2.4.7.3 Disadvantages:.46

2.4.8 Crucible furnace 46

2.4.8.1 Description.46

2.4.8.2 Melting practice .47

2.4.8.3 Advantages: .47

2.4.8.4 Disadvantages:.47

2.4.9 Argon Oxygen Decarburisation (AOD) converter for steel refining .48

2.4.10 Vacuum Oxygen Decarburisation converter (VODC) for steel refining .48

2.4.11 Metal treatment of steel.49

2.4.12 Cast iron treatment 50

2.4.12.1 Alloying .50

2.4.12.2 Homogenisation.50

2.4.12.3 Desulphurisation and recarburisation of cupola melted iron .50

2.4.12.4 Nodularisation treatment of the melt .51

2.4.12.5 Inoculation of the melt.52

2.4.13 Non-ferrous metal treatment52

2.5 Mould and core production.53

2.5.1 Raw materials54

2.5.1.1 Refractory materials.54

2.5.1.1.1 Silica sand .55

2.5.1.1.2 Chromite sand .56

2.5.1.1.3 Zircon sand56

2.5.1.1.4 Olivine sand 56

2.5.1.2 Binders and other chemicals 57

2.5.1.2.1 Bentonite .57

2.5.1.2.2 Resins 57

2.5.1.2.3 Coal dust58

2.5.1.2.4 Cereal binders59

2.5.1.2.5 Iron oxide 59

2.5.1.3 Running, gating, feeding and filtration 59

2.5.2 Sand preparation (transport, sieving, cooling, mixing) .60

2.5.2.1 Sand conditioning for green sand moulding 60

2.5.3 Moulding with natural sand.62

2.5.4 Moulding with clay-bonded sand (green sand moulding) .62

2.5.5 Moulding with unbonded sand (V-process) 63

2.5.6 Moulding and core-making with chemically-bonded sand65

2.5.6.1 Cold-setting processes .65

2.5.6.1.1 Phenolic, acid catalysed 65

2.5.6.1.2 Furan, acid catalysed .66

2.5.6.1.3 Polyurethane (phenolic isocyanate).66

2.5.6.1.4 Resol – ester (alkaline phenolic ester hardened) .67

2.5.6.1.5 Alkyd oil, unbaked 67

2.5.6.1.6 Ester silicate 67

2.5.6.1.7 Cement 67

2.5.6.2 Gas-hardened processes.67

2.5.6.2.1 Cold-box (amine hardened phenolic urethane)68

2.5.6.2.2 Resol – ester (alkaline phenolics methyl formate hardened).68

2.5.6.2.3 SO2 hardened furan resins .69

2.5.6.2.4 SO2 hardened epoxy/acrylic (free radical curing) .69

2.5.6.2.5 CO2 hardened sodium silicate (water glass) 69

2.5.6.2.6 CO2 hardened alkaline phenolic 70

2.5.6.3 Hot curing processes . 70

2.5.6.3.1 Hot-box, phenolic and/or furan based. 70

2.5.6.3.2 Warm-box. 71

2.5.6.3.3 Shell (Croning) . 71

2.5.6.3.4 Linseed oil 72

2.5.6.3.5 Alkyd oil, baked 72

2.5.6.4 Coating of chemically-bonded sand moulds and cores . 73

2.5.6.4.1 Composition of coatings . 73

2.5.6.4.2 Coating process. 73

2.5.7 Expendable pattern casting . 74

2.5.7.1 Unbonded sand – Lost Foam process 74

2.5.7.2 Chemically-bonded sand – Full mould process. 76

2.5.8 Permanent (metal) moulds preparation . 77

2.5.9 Investment casting and ceramic shell 77

2.6 Casting 79

2.6.1 Casting in lost moulds. 79

2.6.1.1 Pouring 79

2.6.1.2 Solidification (1st cooling). 81

2.6.1.3 Shake-out 82

2.6.1.4 Casting cooling (2nd cooling) 82

2.6.2 Casting in permanent moulds 82

2.6.2.1 Gravity and low-pressure die-casting 82

2.6.2.2 High-pressure die-casting 84

2.6.2.3 Centrifugal casting 86

2.6.2.4 Continuous casting 86