technical data

As a reference for our customers, we have produced the reference book
"Wires and rolled wires for electrical heating," which includes approximately 130 pages of these findings.
If you would like to obtain a copy of this reference book, please contact us and we will send you a copy at actual cost.

Silver Kohki Co., Ltd.

Wires and rolled wires for electrical heating(A grounding on their characteristics and application engineering)

Taisuke Kiyota
Graduated from Kumamoto University, Faculty of Engineering, Department of Metallurgy
Work experience
Nippon Metal Industry Co., Ltd., Silver Kohki Co., Ltd.


1.Symbols and chemical compositions
1-1 Characteristics required to elements
1-2 Chemical elements
1-3 Symbols and chemical compositions
2.Physical, Chemical and mechanical properties
3.Electric resistance
3-1 Calculating equations
3-2 Expressing ways of resistivity
3-3 Resistivity with temperature
3-4 Effect of processing on resistivity
4.Life,durability,circumstance and oxide film
4-1 Accelerated life test
4-2 Effect of temperature on the life value
4-3 Oxide film and chromium's function
4-4 Characteristics required to oxide film
4-5 Improvements of oxide film
4-6 Chemical structure of oxide film
4-7 Element life with foreign substances
4-8 Effect of temperature on tensile strength
4-9 Maximum operating temperture with diameter
5.Design and fabrication
5-1 At the beginning in heating element design
5-2 Recommendable symbols for specified conditions
5-3 Ohm's law
5-4 Calculation example for appliance's element
5-5 Calculation example for furnace's element (1)
5-6 Calculation example for furnace's element (2)
5-7 Meaning of surface watts density
5-8 Calculation example using a surface watts density
5-9 Spiralling
(1)D/d ratio
(3)Unevenness of the pitch
(4)Close wound spiral
5-10 Termination (Terminals, leads and jointings)
(1)Requirements for teminal alloys
(2)Recommendable alloys for terminals
(3)Unrecommendable alloys for terminals
(4)Cross-sectional area of terminal rod
(5)Lead wire
5-11 Faults depending on the temperature
(1)Fault against bending stress in hot
(2)Low temperature brittleness
(3)475°C brittleness
(4)Elevated temperature brittleness
5-12 Welding
5-13 Green rot
5-14 Sulphur attack
5-15 Current required to a given temperature
5-16 Typical ways of heating elements
5-17 Oxide film for electrical insulation
6-1 Resistivity
6-2 Tensile strength, Elongation and Newton
6-3 Stress, strain and Young's modulus
6-4 Density, specific heat, emissivity and
6-5 Equations of resistance, length and
6-6 Characteristics depending on the lattice
6-7 Terms relating to recrystallization
6-8 Lattice defect of metals
6-9 Reasons on the increasing tendency of
6-10 Specifications on the the standard
6-11 Equations relating to the ratio of
6-12 Equations relating to the output
6-13 On the life of heating element
6-14 Recommendable symbols depending on
6-15 On the naming of chemical elements used
7.Some applications with photos
Wire gauge size equivalents

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