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| 1. Heating elements |
| ...A. Chemical
composition of heating wire and ribbon (flat
wire) |
| Type |
NI |
Cr |
AI |
C |
Si |
Mn |
Fe |
| NCH-1 |
77 or up |
19-21 |
|
0.15 or up |
0.75-1.5 |
2.5 or up |
1 or up |
| NCH-2 |
57 or up |
15-18 |
|
0.15 or up |
0.75-1.5 |
1.5 or up |
Balance |
| NO.30 |
|
23-26 |
4-6 |
0.10 or up |
1.5 or up |
1.0 or up |
Balance |
| FCH-1 |
|
23-26 |
4-6 |
0.10 or up |
1.5 or up |
1.0 or up |
Balance |
| FCH-2 |
|
17-21 |
2-4 |
0.10 or up |
1.5 or up |
1.0 or up |
Balance |
|
| ....* Classification
of heating wires |
....- Classified
into NCH1 (nickel-chromium class 1), NCH2(nickel-chromium
class 2), FCH1(iron-
..... chromium
class 1) and FCH2(iron-chromium class 2).
NCH1 and NCH2 are attracted by a magnet,
..... but not
FCH1 and FCH2. |
| |
| ...B. Mechanical
and electrical properties of heating wires |
| Type |
Max tolerable temp ℃ |
Elongation
% |
Volume resistance
20℃ |
Density |
Oxide weight
㎎/㎠ |
Life cycle cost, test
method, times |
| NCH-1 |
900-1000 |
20 or up |
108 |
8.41 |
0.5 or up |
1, 1200℃, 300 or up |
| NCH-2 |
900-1000 |
20 or up |
112 |
8.25 |
1.0 or up |
1, 1200℃, 200 or up |
| NO.30 |
700-800 |
13 or up |
142 |
7.20 |
0.1 or up |
U, 1300℃, 200 or up |
| FCH-1 |
700-800 |
10 or up |
142 |
7.20 |
0.3 or up |
U, 1300℃, 100 or up |
| FCH-2 |
700-800 |
10 or up |
123 |
7.35 |
0.5 or up |
U, 1300℃,
50 or up |
|
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| ...C. Characteristics
of wires |
| Type |
Symbol |
Reference |
| Characteristics
and usages |
전
열
용
니
켈
크
롬 |
Wire |
Class
1 |
NCHW
1 |
Nickel-chromium
heating wire and ribbon class 1
It has excellent acid resistance
and high temperature strength, but should
not be used in sulfuric gas and in a
high temperature, or a high-humidity
reducing atmosphere. It does not become
brittle even after heating at a high
temperature, and exhibits good cold
workability. The maximum tolerable temperature
is about 1,100°C (at the heating surface)
and the material can be widely suitable
for a high-temperature heating element.
Nickel-chromium heating
wire and ribbon class 2
Acid resistance and high temperature
strength are slightly lower than class
1. The maximum tolerable temperature
is about 1, 000°C (at the heating surface),
suitable for a high temperature heating
element. |
Class
2 |
NCHW
2 |
| Rib-bon |
Class
1 |
NCHRW
1 |
Class
2 |
NCHRW
2 |
전
열
용
니
켈
크
롬 |
Wire |
Class
1 |
FCHW
1 |
Iron-chromium
heating wire and ribbon class 1
This is specifically for high temperature.
It has excellent acid resistance but
low high temperature strength, and thus
requires caution. In case cold working
is difficult, warm working (100~300°C)
may be necessary. However, working after
use at a high temperature should be
avoided. The maximum tolerable temperature
is about 1250°C (at the heating surface),
suitable for a high temperature heating
element.
Iron-chromium heating wire and ribbon
class 2
Cold workability is slightly better
than iron-chromium heating wire and
ribbon class 1, however, caution should
be exercised to the fact that high temperature
strength is lower than nickel-chromium
heating wire and ribbon and that working
after use at a high temperature should
be avoided, just like in case of iron-chromium
heating wire and ribbon class 1. The
maximum tolerable temperature is about
1100°C (at the heating surface), suitable
for a high temperature heating element. |
Class
2 |
FCHW
2 |
| Rib-bon |
Class
1 |
FCHRW
1 |
Class
2 |
FCHRW
2 |
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| It is a widely known fact that the
surface temperature should be about
350oC, and from the above graph, the
rate of temperature increase of the
heating wire at 350oC is 1.013%.That
is, according to Ohm’s law, the resistance
calculated for 220V-148W is 327 327Ω,
but with reference to the above graph,
we get 323.7Ω by subtracting 3.3 Ω as
the actual resistance for 220V-148W. |
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| △ top... |
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| 2. PIPE |
| ...A. Properties
stainless steel tubes |
| AISI |
W. |
APPLICATION FIELD |
| 304 |
1.4301 |
In
water or humid environment max. 450°CIn
air max. 700°CScale temperature 850°C |
| 304 L |
1.4301 |
As AISI 304-W 1. 4301
for more corrosive humid environmentsTube
used for washing machine heating elements |
| 321 |
1.4306 |
Tube
for washing and cooking heating elementsIn
water or humid environment max. 550°CIn
air max. 750°CScale temperature 850°C |
| 316 |
1.4541 |
It corresponds to AISI
304L-W 1.4306, with addition of Molybdenum,to
improve the resistance to corrosion
caused by pitting and by under tension.In
water or humid corrosive environment
max. 450°C |
| 316
L |
1.4401 |
t
corresponds to AISI 304L-W 1.4306, with
addition of Molybdenum As well as improving
the resistance to corrosion caused by
pitting and byunder tension, it allows
a better behaviour to general corrosionIn
water or humid corrosive environment
max. 450°C |
| 316 Ti |
1.4404 |
It corresponds
to AISI 321-W 1.4541, with addition
of Titanium as well asMolybdenum. The
addition of Titanium is an alternative
to the use of AISI 316L,For temperatures
of 500°C, in non continuous operation. |
| 309
S |
1.4571 |
In
air, for max. temperatures up to 950°CTypical
use for heating elements in fan forced
oven-grills |
| 310 S |
1.4828 |
In water or
humid mixed air/water environments,
with max. temperature up to 550°CCharacteristic
colour after annealing : dark green |
| INCOLOY804 |
1.4842 |
In
air for max. temperatures up to 950°CIn
all the applications for which the characteristics
of AISI 309 S-W 1.4828 are not satisfactory |
| INCONEL601 |
2.4851
|
In air for
max. temperatures of 1100°CIn water
or corrosive environments with high
concentration of Chloride ions |
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| ...B. Max recommended
Tube temp (UL 1030) |
| Tube Material |
| Designation |
Composition |
Max. operating temp °C |
| |
Copper |
180 |
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Aluminium |
260 |
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Brass |
400 |
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Steel |
400 |
| AISI
303/304 |
18Cr
8Ni |
760 |
| 316 |
18Cr
8Ni, Mo |
760 |
| 321 |
18Cr
8Ni Ti |
760 |
| 310
|
25
Cr 20Ni |
870 |
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Nickel
Alloys |
|
| Monel
400 |
65
Ni 35 Cu |
480 |
| Incoloy
800 |
35
Ni 20 Cr |
930 |
| Inconel
600 |
75 Ni 15 Cr |
980 |
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top. |
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