VIEW THE MOBILE VERSION of Informational Site Network Informational
   Home - Steel Making - Categories - Manufacturing and the Economy of Machinery

Steel Making

An Automatic Temperature Control Pyrometer
Automatic temperature control instruments are similar to the ...

Introduction Of Carbon
The matter to which these notes are primarily directed is the...

Making Steel Balls
Steel balls are made from rods or coils according to size, st...

Robert Mushet
Robert (Forester) Mushet (1811-1891), born in the Forest of D...

Liberty Motor Connecting Rods
The requirements for materials for the Liberty motor connecti...

High Speed Steel
For centuries the secret art of making tool steel was handed ...

Rate Of Absorption
According to Guillet, the absorption of carbon is favored by ...

Hardness Testing
The word hardness is used to express various properties of me...

Lathe And Planer Tools
FORGING.--Gently warm the steel to remove any chill, is parti...

Steel For Chisels And Punches
The highest grades of carbon or tempering steels are to be re...

Using Illuminating Gas
The choice of a carburizing furnace depends greatly on the fa...

Application To The Automotive Industry
The information given on the various parts of the Liberty eng...

Heat Treatment Of Lathe Planer And Similar Tools
FIRE.--For these tools a good fire is one made of hard foundr...

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

Chrome-nickel Steel
Forging heat of chrome-nickel steel depends very largely on ...

The Effect Of Tempering On Water-quenched Gages
The following information has been supplied by Automatic and ...

Tungsten, as an alloy in steel, has been known and used for a...

S A E Heat Treatments
The Society of Automotive Engineers have adopted certain heat...

Heat Treatment Of Axles
Parts of this general type should be heat-treated to show the...

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

Heavy Forging Practice

Category: FURNACES

In heavy forging practice where the metal
is being worked at a welding heat, the amount of flame that will
issue from an open-front furnace is so great that a plain, sheet-steel
front will neither afford sufficient protection nor stand up in
service. For such a place a water-cooled front is often used. The
general type of this front is illustrated in Fig. 103, and appears to
have found considerable favor, for numbers of its kind are scattered
throughout the country.

In this case the shield is placed at a slight angle from the vertical,
and along the top edge is a water pipe with a row of small holes
through which sprays of water are thrown against it. This water runs
down in a thin sheet over the shield, cooling it, and is collected
in a trough connected with a run-off pipe at the bottom. The lower
blast-pipe arrangement is similar to the one first described.

There are several serious objections to this form of shield that
should lead to its replacement by a better type; the first is that
with a very hot fire, portions in the center may become so rapidly
heated that the steam generated will part the sheet of water and
cause it to flow from that point in an inverted V, and that section
will then quickly become red hot. Another feature is that after
the water and fire are shut down for the night the heat of the
furnace can be great enough to cause serious warping of the surface
of the shield so that the water will no longer cover it in a thin,
uniform sheet.

After rigging up a big furnace with a shield of this type several
years ago, its most serious object was found in the increase of
the water bill of the plant. This was already of large proportions,
but it had suddenly jumped to the extent of several hundred dollars.
Investigation soon disclosed the fact that this water shield was one
of the main causes of the added cost of water. A little estimating
of the amount of water that can flow through a 1/2-in. pipe under
30-lb. pressure, in the course of a day, will show that this amount
at 10 cts. per 1,000 gal., can count up rather rapidly.

Figure 103 is a section through a portion of the furnace front and
shield showing all of the principal parts. This shield consists
essentially of a very thin tank, about 2-1/2 in. between walls,
and filled with water. Like other shields it is fitted with an
adjustment, that it may be raised and lowered as the work demands.
The tank having an open top, the water as it absorbs heat from
the flame will simply boil away in steam; and only a small amount
will have to be added to make up for that which has evaporated. The
water-feed pipe shown at F ends a short distance above the top
of the tank so that just how much water is running in may readily
be seen.

An overflow pipe is provided at O which aids in maintaining the
water at the proper height, as a sufficient quantity can always be
permitted to run in, to avoid any possibility of the shield ever
boiling dry; at the same time the small excess can run off without
danger of an overflow. The shield illustrated in Fig. 104 has been
in constant use for over two years, giving greater satisfaction
than any other of which the writer has known. It might also be
noted that this shield was made with riveted joints, the shop not
having a gas-welding outfit. To flange over the edges and then
weld them with an acetylene torch would be a far more economical
procedure, and would also insure a tight and permanent joint.

The water-cooled front shown in Fig. 105 is an absurd effort to
accomplish the design of a furnace that will provide cool working
conditions. This front was on a bolt-heating furnace using hard
coal for fuel; and it may be seen that it takes the place of all
of the brickwork that should be on that side. Had this been nothing
more than a very narrow water-cooled frame, with brickwork below
and supporting bricks above, put in like the tuyeres in a foundry
cupola, the case would have been somewhat different, for then it
would have absorbed a smaller proportion of the heat.

A blacksmith who knows how a piece of cold iron laid in a small
welding furnace momentarily lowers the temperature, will appreciate
the enormous amount of extra heat that must be maintained in the
central portion of this furnace to make up for the constant chilling
effect of the cold wall. Moreover, since there would have been
serious trouble had steam generated in this front, a steady stream
of water had to be run through it constantly to insure against
an approach to the boiling point. This is illustrated because of
its absurdity, and as a warning of something to avoid.

Water-cooled, tuyere openings, as mentioned above, which support
brick side-walls of the furnace, have proved successful for coal
furnaces used for forging machine and drop-hammer heating, since
they permit a great amount of work to be handled through their
openings without wearing away as would a brick arch. Great care
should be exercised properly to design them so that a minimum amount
of the cold tuyere will be in contact with the interior of the
furnace, and all interior portions possible should be covered by
the bricks. However, a discussion of these points will hardly come
in the flame-shield class, although they can be made to do a great
deal toward relieving the excessive heat to be borne by the furnace

Next: Flange Shields For Furnaces

Previous: Protective Screens For Furnaces

Add to Add to Reddit Add to Digg Add to Add to Google Add to Twitter Add to Stumble Upon
Add to Informational Site Network

Viewed 3153