Cellulose is the main constituent of the structure of plants (natural polymer) that, when extracted, is employed for making paper, plastics, and in many combinations. Cellulose is made up of long-chain molecules in which the complex unit C6H10O5 is repeated as many as 2000 times. It consists of glucose molecules with three hydroxyl groups for each glucose unit.
Cast Stainless Steels
|
Corrosion-Resistant Grades (ACI Designation) |
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 |
 |
 |
 |
 |
 |
CG-6 |
CF-10 |
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 |
 |
 |
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|
HC |
HE |
HF |
HH |
HT |
HX |
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|
Equivalent AISI Gradesg |
UNS |
|||||||||
|
410 |
442 |
446 |
312 |
304 |
309 |
330 |
S20910 |
S21800 |
||
 |
||||||||||
|
Grades |
100 |
60 |
65 |
63 |
35-40 |
50 |
— |
— |
50 |
47 |
|
HR grades |
— |
— |
75 |
45 |
45 |
50 |
40 |
25 |
40 |
— |
 |
115 |
95 |
70-110 |
87-92 |
75-92 |
80-88 |
69-70 |
56-75 |
94 |
96 |
 |
35 |
2 |
45 |
10 |
70 |
15 |
4 |
— |
71 |
134 |
 |
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|
HR grades only, |
— |
— |
1.3 |
3.5 |
6 |
7.0 |
8.0 |
6.4 |
— |
— |
|
1400°F |
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|
1800°F |
— |
— |
0.336 |
1.0 |
3.2 |
2.1 |
2.0 |
1.6 |
— |
— |
|
Elongation (%) |
||||||||||
|
R grades |
29 |
— |
29 |
35 |
28 |
28 |
27 |
25 |
28 |
26 |
|
Hardness, Bhn |
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|
CR grades |
225 |
195 |
210 |
190 |
140 |
190 |
— |
— |
210 |
195 |
|
HR grades |
— |
— |
223 |
200 |
165 |
185 |
180 |
176 |
— |
— |
|
Melting temperature |
2700- |
2700- |
2650- |
2600- |
2550- |
2500- |
2400- |
2350 |
— |
— |
|
(°F) |
2790 |
2750 |
2750 |
2700 |
2600 |
2600 |
2450 |
|||
|
Coefficient of thermal expansion |
||||||||||
 |
5.5 |
5.7 |
5.9 |
9.0 |
8.3 |
9.0 |
8.8 |
|||
|
70-1000°F |
6.4 |
6.5 |
6.4 |
9.6 |
10.9 |
9.6 |
9.8 |
9.5 |
10.2 |
10.0 |
 |
14.5 |
12.8 |
12.6 |
10.0 |
9.0 |
8.2 |
7.7 |
11.1 |
9.0 |
|
 |
0.275 |
0.2720.274 |
0.2720.277 |
0.276 |
0.280 |
0.279 |
0.286 |
0.294 |
0.285 |
0.276 |
|
Electrical resistivity, |
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|
CR grades (microhm-cm) |
78.0 |
76.0 |
77.0 |
85.0 |
76.2 |
84.0 |
— |
— |
82.0 |
98.2 |
|
Magnetic |
Yes |
Yes |
Yes |
Partially |
CF, partially, HF, no |
Partially |
Partially |
Slightly |
Slightly |
|
Note: CR = corrosion resistant; HR = heat resistant.
a 1800°F air cooled, 1200°F tempered. b 1450°F air cooled. c 1900°F air cooled. d 2000°F air water quenched. e >1900°F water quenched. f As cast.
g Equivalent wrought grades are given for comparison only; the ACI designations, generally included in ASTM A743 and A297, are used to specify the cast stainless steel grades. h Annealed.
Cellulose is the most abundant of the non-protein natural organic products. It is highly resistant to attack by the common microorganisms. However, the enzyme cellulase digests it easily, and this substance is used for making paper pulp, for clarifying beer and citrus juices, and for the production of citric acid and other chemicals from cellulose. Cellulose is a white powder insoluble in water, sodium hydroxide, or alcohol, but it is dissolved by sulfuric acid.
One of the simplest forms of cellulose used industrially is regenerated cellulose, in which the chemical composition of the finished product is similar to that of the original cellulose. It is made from wood or cotton pulp digested in a caustic solution. Cellophane is a regenerated cellulose in thin sheets for wrapping and other special uses include windings on wire and cable.
