Steelmaking.ca Home Steel Making Categories Manufacturing and the Economy of Machinery

Steel Making

Temperature Recording And Regulation
Each furnace is equipped with pyrometers, but the reading an...

Annealing Of High-speed Steel
For annealing high-speed steel, some makers recommend using g...

Vanadium
Vanadium has a very marked effect upon alloy steels rich in c...

High-chromium Or Rust-proof Steel
High-chromium, or what is called stainless steel containing f...

The Quenching Tank
The quenching tank is an important feature of apparatus in c...

Open Hearth Process
The open hearth furnace consists of a big brick room with a l...

Cutting-off Steel From Bar
To cut a piece from an annealed bar, cut off with a hack saw,...

Conclusions
Martien was probably never a serious contender for the honor ...

Blending The Compound
Essentially, this consists of the sturdy, power-driven separa...

Tempering Colors On Carbon Steels
Opinions differ as to the temperature which is indicated by t...

Annealing Method
Forgings which are too hard to machine are put in pots with ...

Heating
Although it is possible to work steels cold, to an extent de...

Pyrometry And Pyrometers
A knowledge of the fundamental principles of pyrometry, or th...

Application Of Liberty Engine Materials To The Automotive Industry
The success of the Liberty engine program was an engineer...

Steel Worked In Austenitic State
As a general rule steel should be worked when it is in the a...

Tool Or Crucible Steel
Crucible steel can be annealed either in muffled furnace or b...

Hardening Operation
Hardening a gear is accomplished as follows: The gear is tak...

Tempering Round Dies
A number of circular dies of carbon tool steel for use in too...

Refining The Grain
This is remedied by reheating the piece to a temperature slig...

Gears
The material used for all gears on the Liberty engine was sel...



Furnace Data






Category: PYROMETRY AND PYROMETERS

In order to give definite information concerning furnaces, fuels
etc., the following data is quoted from a paper by Seth A. Moulton
and W. H. Lyman before the Steel Heat Treaters Society in September,
1920.

This considers a factory producing 30,000 lb. of automobile gears
per 24 hr. The transmission gears will be of high-carbon steel and
the differential of low-carbon steel, carburized. The heat-treating
equipment required is:

1. Annealing furnaces 1,400 to 1,600 deg.F.
2. Carburizing furnaces 1,700 to 1,800 deg.F.
3. Hardening furnaces 1,450 to 1,550 deg.F.
4. Drawing furnaces 350 to 950 deg.F.

All of the forging blanks are annealed before machining, about
three-quarters of the machined gears and parts are carburized,
all the carburized gears are given a double treatment for core and
case, all gears and parts are hardened and all parts are drawn.

The possible sources of heat supply and their values are as follows:--

1. Oil 140,000 B.t.u. per gallon
2. Natural gas 1,100 B.t.u. per cubic foot
3. City gas 650 B.t.u. per cubic foot
4. Water gas 300 B.t.u. per cubic foot
5. Producer gas 170 B.t.u. per cubic foot
6. Coal 12,000 B.t.u. per pound
7. Electric current 3,412 B.t.u. per kilowatt-hour

For the heat treatment specified only comparatively low temperatures
are required. No difficulty will be experienced in attaining the
desired maximum temperature of 1,800 deg.F. with any of the heating
medium above enumerated; but it should be noted that the producer
gas with a B.t.u. content of 170 per cubic foot and the electric
current would require specially designed furnaces to obtain higher
temperatures than 1800 deg.F.

TABLE 28.--COMPARATTVE OPERATING COSTS

Assuming
Cost of oil- and gas-fired furnaces
installed as $100.00 per square foot of hearth
Cost of coal-fired furnace installed as 150.00 per square foot of hearth
Cost of electric furnace 100 kw.
capacity installed as 90.00 per kilowatt
Cost of electric furnace 150 kw.
capacity installed as 70.00 per kilowatt

Output 3,000 lb. charge, 8 hr. heat carburizing, 2 hr. heating
only. Annual service 7,200 hr. Fixed charges including interest,
depreciation, taxes, insurance and maintenance 15 per cent. Extra
operating labor for coal-fired furnace 60 cts. per hour, one man
four furnaces.

COST OF VARIOUS TYPES OF FURNACES
-------------------------------------------------------------------------------
Class fuel Fuel per Unit fuelInstallationEfficiency Fixed Cost per
charge cost cost per cent charges charge
------------------------------------------------------------------------
1 2 3 4 5 6 7
------------------------------------------------------------------------
Carburizing
------------------------------------------------------------------------
1Oil 52.0 gal. $0.15 gal. $2,400.00 12.6 $.40 $8.20
2Natural gas 4.4 M 0.50 M 2,400.00 18.8 0.40 2.60
3City gas 8.3 M 0.80 M 2,400.00 17.0 0.40 7.04
4Water gas 18.7 M 0.40 2,400.00 16.4 0.40 7.88
5Producer gas 37.3 M 0.10 M 2,400.00 14.5 0.40 4.13
6Coal 814.0 lb. 6.00 ton 3,600.00 9.4 0.60 3.98
7Electricity 500.0 kw-hr. 0.015 kw. 9,000.00 53.0 1.50 9.00
------------------------------------------------------------------------
Heating
------------------------------------------------------------------------
1Oil 30.8 gal. 0.15 gal. 2,400.00 21.4 0.10 4.72
2Natural gas 2.61 M 0.50 M 2,400.00 32.0 0.10 1.40
3City gas 4.9 M 0.80 M 2,400.00 28.8 0.10 4.02
4Water gas 11.1 M 0.40 M 2,400.00 27.6 0.10 4.54
5Producer gas 22.1 M 0.10 M 2,400.00 24.6 0.10 2.31
6Coal 348.0 lb. 6.00 ton 3,600.00 22.0 0.15 1.38
7Electricity 329.0 kw-hr. 0.015 kw. 10,500.00 81.75 0.44 5.38
-------------------------------------------------------------------------------

This shows but two of the operations and for a single furnace.
The total costs for all operations on the 30,000 lb. of gears per
24 hr. is shown in Table 29.

TABLE 29.--COMPARATIVE ANNUAL PRODUCTION COSTS FOR 30,000 POUNDS
OUTPUT IN 24 HOURS

----------------------------------------------------------
No. Equipment Installation
cost
--------------------------------------------------------
1 2 3

I Oil $179,000.00
II Oil and electric 213,000.00
III Natural gas 117,000.00
IV (A) Natural gas containing furnaces 120,000.00
V Natural gas and electric 181,000.00
VI City gas 122,000.00
VII City gas and electric 182,000.00
VIII Water gas 214,000.00
IX Water gas and electric 238,000.00
X Producer gas 246,000.00
XI Producer gas and electric 255,000.00
XII Coal and electric 194,000.00
XIII Electric 257,000.00
----------------------------------------------------------

---------------------------------------------------------------------
Annual operating expenses Cost
No. ---------------------------------------- Total per lb.
Fixed Heat Labor metal,
charges cents
----------------------------------------------------------------
1 4 5 6 7 8

I $26,850.00 $156,000.00 $105,000.00 $287,850.00 $3.19
II 31,950.00 142,770.00 97,000.00 271,720.00 3.02
III 17,550.00 44,250.00 97,000.00 158,800.00 1.78
IV 18,000.00 41,000.00 94,000.00 153,000.00 1.70
V 27,150.00 73,820.00 90,000.00 190,970.00 2.13
VI 18,300.00 123,200.00 94,000.00 235,500.00 2.62
VII 27,300.00 128,820.00 90,000.00 246,020.00 2.74
VIII 18,600.00 104,000.00 94,000.00 216,600.00 2.41
IX 27,450.00 117,420.00 90,000.00 234,870.00 2.62
X 18,900.00 69,300.00 90,000.00 178,200.00 1.98
XI 27,750.00 92,520.00 90,000.00 210,270.00 2.34
XII 29,100.00 87,220.00 90,000.00 206,320.00 2.30
XIII 38,550.00 135,000.00 84,000.00 257,550.00 2.86
---------------------------------------------------------------------

NOTE.--Producer plant fixed charges are included in the cost of
gas and are charged as heat in column 5, so they are omitted
from column 4.





Next: Pyrometry And Pyrometers

Previous: Heating Of Manganese Steel



Add to Informational Site Network
Report
Privacy
ADD TO EBOOK


Viewed 4744