Kanthal handbook : resistance heating alloys for industrial furnaces / Kanthal

CONTENIDO
Introduction 11
Tables of Figures 9
1. HEATING ALLOYS
Resistance Heating Alloys 13
Ferritic Alloys (FeCrAl) 13
Austenitic Alloys (NiCr and NiCrAl) 13
2. PROPERTIES
Physical and Mechanical Properties 15
List of Properties 15
3. CONVERSION
Conversion from Nickel-Chromium to KANTHAL Alloys 17
General 17
Summary of KANTHAL and NIKROTHAL Advantages 17
KANTHAL Advantages 17
NIKROTHAL Advantages 18
Weight Savings 18
Applications 18
4. DESIGN FACTORS
Design Factors 21
Operating Life 21
Maximum Permissible Temperature 22
Wire Size 22
Furnace Atmospheres 23
Corrosion Resistance 24
Gaseous Impurities 24
Salts and Oxides, Metals 24
Ceramic Support Materials 25
Embedding Compounds 25
5. ELEMENTS
Elements in Furnaces 27
General Considerations 27
Initial Factors 27
Furnace Temperatures 27
Furnace Power 27
Mode of Operation 28
Furnace Voltage 28
Furnace Wall Loading 28
6. DESIGN CALCULATIONS
Design Calculations 31
Element Surface Load 31
Design of Wire Elements 33
Calculation for Wire Diameter 33
Calculation of a Spiral Element 34
Design of Strip Elements 35
Determination of a Suitable Strip Size 35
Calculation of Strip Width, Thickness and Length 35
Determination of Element Dimensions 36
Design of Freely Radiating Wire and Strip Elements 38
Deep Corrugated Kanthal AF Strip Elements 39
Deep Corrugated Kanthal AF Wire Element 42
7. FORMS AND SUPPORT
Element Forms and Support Systems 47
General 47
Applications 47
Use of Ceramic Support Materials 54
Radiant Tubes 54
Electrical Regulating Resistors 57
Furnace Insulation Materials 57
Support Systems 58
8. APPLICATIONS
Applications 65
9. DELIVERY FORMS
Delivery Forms, Surtace Finish and Tolerances tor Wire and Strip 69
Delivery Forms 69
Wire 69
Strip 70
Surface Finish 70
Delivery Tolerances 71
Delivery Forms, USA Market 71
10. TABLES
Data tor KANTHAL, ALKROTHAL and NIKROTHAL Alloys 73
Metric 73
Imperial 95
Terminals 126