Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a method o~ and apparatus
~or making metal products in which small pieces o~ scrap are
fed simultaneously with molten metal into a recei~er ~uch as
a ladle or mold. The rapid growth in the use of oxygen
converters for making steel, replacing open hearth furnaces,
has created an excess o~ steel scrap becau~e the oxygen
converter had definite limlts on the percentage o~ scrap
which can be used, in contrast to the open hearth ~urnace
which has no such limits. The scrap ~enerated in steel-
making plants and in steel users fabricating operations isan excellent source o~ metallics of known analysis~ and
steel companies have ~or many years sought ways of best
utiliæing larger proport1ons o~ this scrap than are normal
to the oxygen converter process. A11 o~ the methods now in
15 common u3e, require complete remelting o~ scrap in separate '
J facilities with the attendant high cost o~ ~acilities and
operations and enviro~mental controls. It is common practice
in making steel to produce the steel in ~urnaces such as open
hearths, oxygen converters and electrlc furnacesc ~he molten
steel is then poured ~rom the ~urnace into a ladle and then
from the ladle into a mold, which ma~ be an ingot n~ld, a
continuous casting mold or a mold shaped to provide a casting
as a finished product except ~or machining. For~various
reasons the temperature o~ the molten steel a~ter being
poured into the ladle may be higher than the proper
; temperature for pouring into the mold. In some instances
non-metallic material~ are added either in the ~urnace or in
the ladle to lower this tsmperature, but such additions do
not substantially raise the ~eight of the charge and are
mere1y an added expense. In other instances the molten
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steel is held ~or a time in the ladle to allov~ it to cool, or
i9 re-ladled (poured ~rom ladle to ladle) to cool it. Such
practices can delay production and add expense
According to my invention steel scrap Or known analysis,
properly sized~ cleaned and heated su~ficiently to remove
substantially all the moisture there~rom, is thrown through a
closed chute in small pieces at a controlled rate and velocity
into the ~adle simultaneously with the pouring of the molten
metal. The amount o~ added scrap is su~ficient to lower the
temperature o~ the mixture to that desired for pouring into
the mold while limited to an amount which will melt so a~ to
obtain ~ homogeneous mixture, Since the scrap is added to
the ladle simultaneously with the hot metal~ and proportion-
ately thereto, the temperature o~ the steel is reduced
15 uniformly. There are none of the temperature variations and
"cold spots" rrhich will occur i~ 9 crap is added in conven-
tional forms or by other methods0 The same method may be used
~n the manu~acture o~ other metals.
I have ~ound that when steel scrap o~ known analysis
is properly sized, cleaned and heatsd suf~iciently to remove
the moi~t~re there~rom3 ~ed to an ingot mold through a closed
chute at a controlled rate and velocity along with molten
stael o~ a similar analysis in an amount such that the
majority thereof will not melt in the mold~ and the resulting
ingot processed in the usual manner to obtain sheets~ the
resulting steel is of such quality that it can be used ~or
many products in the same manner as standard sheets.
In an e~ort to avoid the necessity o~ melting scrap~
it has been suggested and tried to assemble pieces of scrap
ln various ways, then heat them ~o rolling temperaturo, and
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then roll on conventional rolling equipment~ but ~hese
processes proved to be uneconomical and unsatisfactory.
While it i3 known to add solids to castings, this has
been done for other reaQonS than to utilize scrap. The
closest art of ~hich I have knowledge are U.S. Patent No.
2,855,646 (Fromson) dated October l~, 1958 and U.S. Patent
No. 3,429,361 (Brooks) dated February 25) 1969, In From~on,
~hot is made from a portion o~ a batch o~ molten metal and
then fed as a solid along with the remainin~ molten metal to
a mold. The temperature and volume are controlled so that
there is "a total amount of heat in the mixture whioh will
cause at least an inclpient ~usion o~ the solid particle~ in
the mixture". The process was developed to control tempera-
ture inside a cacting while pouring the casting and is more
1~ expens~ve than standard casting procedure. The ~asiG method
and purpose o~ the Brooks Patent is similar to that Or
Fromson~s in that it represents an approach to controlling
temperature inqide a continuous casting mold while pouring.
The amount of heat in a normal mold of molten steel is n~t
sufficient to melt the majority of the scrap which I add, but
I have found that this is not necessary. My process does not
require special temperature control or special roll~ng prac-
; tices,
It is therefore an ob~ect of my invention to provide
a method of making a metal product which utilizes a ~ubstantialamount o~ scrap without requiring the e~pensive ~acilities
needed to melt the ~crap.
Another object i3 to provide such a method ln which
the scrap and molten metal are ~ed into a ladle with the
amount of scrap being limited to that which can ~ ~elted.
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A ~urther ob~ect is to pro~ide such a method in which
the 3crap and molten metal are fed into a mold with the ~mount
Or scrap being such that the ma~ority thereof will not melt.
A 9till furtherob~ect o~ the invention consists in
providing an apparatus ~or ~eeding scrap into a container,
such as a mold or ladle~ at the same time as molten metal i~
poured into the container.
These and other objects will become more apparent after
referring to the following specifications and dra~ings, in
whiCh
Figure 1 is an ele~ation, partly ln ~ection, showing
apparatus suitable for carrying out my invention,
Figure 2 is a plain view of Figure 1 with upper parts
removed;
Figure 3 is a plain ~iew showing a modified end o~
the scrap chute,
F~gure 4 i9 a side ele~ation o~ ~igure 3,
Figure 5 is a view taken on the line V-V o~ Figure 3
~ igure 6 is a ~lew taken on the line VI-VI o~ Figure
5, and
Figure 7 is a v~ew~ similar to Figure 1, showing a
3econd embodiment of my invention.
Referring more particularly to the drawings, reference
numeral 28 represents a supporting struoture made up o~ verti-
cal columns 30 connected by horizontal beams 32. The columnsand beams as ~hown are 4 in, x 6 in. tubing. The bottom o~
structure 28 is shown as being a carriage 34 mounted on
~heels 36. When adding scrap to a plural~ty of ingo~ molds
38, as shown in Figures 1 and 2, the carriage 34 is mounted
on rails 40 provided on pouring floor 42-. A standard throw~ng
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mechanism 44 i~ mounted on carriage 34. As shown, thi~ may
be a Blaw-Knox Dolomite Machine, as shown on Page 1 of their
Bulletin 2421 copyrighted in 1953 by the Blaw-I~nox Co. Th~s
mechanism includes a belt 46 passing around idler pulleys 48
and a grooved throwing wheel 50. Scrap is ~d to the ~heel 50
through a hopper 52. As shown, the wheel 50 i9 driven from a
motor 54 by means of belt 56, In one installation motor 54
is a 20~horsepower, 250 volt D,C. ~otor~ A control 58 varies
the speed of the motor between 850 an~ 2200 R.P~I.I. so that the
velocity of the scrap leaving the throwing meohanism and
delivered to a closed chute 60 will be between 1100 and 3300
ft~ per minute. Details of the chute will be described later.
A standard vibratory feeder 621 such as a ~YNTR0~ Mo.
F4~o, is mounted above the thrower 44. This includes a motor
: 15 64 and a vi~ratlng pan 66 mounted on a support 68. A control
70 for motor 64 determlnes the rate of feed and also enables
the ~eed to be shut of~ quickly. The feeder 62 is supportsd
on column9 30 by means of a spring biased s~pporting hanger 71
at each corner thereof. Up to 6000 lbs. of scrap per minute
may be fed by the vibrator 62 from its pan 68 to hopper 52.
A hopper 72 is mounted at the top o~ supporting
structure 28 with its bottom open to the pan 680 A gate 74
p~voted at 76 to hopper 72 i3 closed during loading of hopper
72 and is raised by means of chain 78 and held in rai3ed
position by means o~ hook 80 50 as to permit dlscharge of the
scrap into hopper 52~ An electrlc heating system 82 is
provided on the outside of all four ~ides of the hopper 72.
Insulat.ion 84 covers all four sides of hopper 72 on the
outside o~ the heating system. A thermostatic control 86 is
preferably provided for the heating system, The h~pper 72
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may be loaded with scrap ln any well-known manner. As showh,
it i9 fed from a tip-over self-righting type bucket ~ mounted
on rail 90. It i9 preferred that the hopper 72 be readily
removable from supporting structure and that a plurality o~
such hoppers be provided for a purpose which will appear
later.
The chute 60 is mounted for movement on a vertical pivot
91. ~Vhile the discharge end of chute 60 may be a plain open
end as shown in Figure 1, it is preferred thak means be
provided to qplit the stream of scrap in half and also to
direct th~ scrap downward at adjustable angle3 to the vertical
so that it will impinge on the falling stream of molten metal
at various vertical locations~ One structure ~or accomplish-
ing thi~ is shown in ~igures 3 to 6. The discharge end of
chute 60 i~ divided into passageways 92 and 94 and a hou~ing
96 is welded or otherwise fastened to and surrounds the
bifurcated ends thereof. If desired~ a baffle plate may be
pivotally mounted at the forward junction of passagsways 92
and 94 and extended toward the entry end of chute 60 in order
to insure equal di~tribution of the scrap lnto the two
streams. By moving the ba~fle plate, equal distribution can
be obtained regardless of the velocity and amount of scrap
being fed~ A scrap guide 98 i~ positioned at the end of eaoh
passageway 92 and 94, Each guide 98 is generally triangular
in vertical section with its hypotenuse having an arcuate
inside ~urfaca and each leg being open~ The one leg is
substantially vertical to receive scrap from itsassociated
passagsway and the other leg substantially horizontal to
discharge scrap downwardly into the moldO Each guide 98 is
supported by a link 100 ha~ing one end pivotally connected
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at 102 to housing 96 and its other end p~votally conne¢ted at
104 to guide 98. A U-shaped bracket 106 i9 s~cured to the top
of housing 96 between links 100 and has a slot 108 therein for
receiving a pin 110. h link 112 has one end pivotally
connected to pin 110 and its other end pivotally connected at
114 to one o~ the links 100. A hand lever 116 has one end
pivotally connected to pin 110 and is pivotally connected
intermediate its ends to the other link 100. A pair o~
brackets 120 are secured to each end o~ the bottom o~ housing
96 in alignment with the centers of guides 98. A rod 122 i~ -
slidably received in each pair of brackets 1~0. A rod 124
passes through each guide 98 adjacent the lower end thereo~-~
The rod 122 is welded to rod 121~ midway of its ends. A rod
128 i9 mounted for rotation in bearings 130 ~ecured to the
bottom o~ housing 96. The rod 128 is rotated b~ means af
hand lever 132 3ecured thereto. One end o~ a link 134 i9
secured to each end of rod 12~ for movement therewith with
its other end pivotally connected to one end of an associated
link 136. A bar 138 extends between and is fastened to the
free ends of links 136 and is provided with openings for
receiving rods 122. Collar3 140 on roas 122 on each side of
bar 138 cause the rods 122 to be moved by bar 138.
Due to various factors, such as the size of the mold,
the height o~ the molten metal in the mold, etc., it ma~ be
desired to change the angle of disoharge o~ the scrap. This
is accomplished by the above structure either before feeding
of the molten metal and s¢rap or during such ~eeding in the
following manner. Movement of hand lever 116 ¢ounter-
clockwise as shown in Figure 3 will cause the ends of le~ers
100 carrying the guides 98 to move apart~ Since the bottom
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of guides 98 are confined by rods 122 this causes the guides
98 to tilt in such a directi~n that the two streams o~ scrap
will tend to converge. Movement i~ the opposite dire~tion
will cause the streams to diverge. Movement of hand lever
132 cloc~ise in Figure 6 will cause the rod 124 and the
bottom of guîde 98 to move to the right. This will cause
the stream~ of scrap to discharge more toward the right side
of the mold 38 as shown in Figure 3. Movemen~ o~ hand lever
132 in the opposite direction will cause discharge more
toward the left side o~ the mold 38. It will be noted that
the various connections to the guides 98 are sloppy to permit
the movements set ~orth above~
In operationJ when charging a plurality of individual
ingot molds 38 as shown in Figures 1 and 2 the supporting
structure 28 is moved along tracks 40 and the chute 60
pivoted into position over the rirst mold to be ~illed. The
levers 116 and 132 are manipulated to direct the scrap ~eed
as desired, The cleaned scrap is heated to the required
temperature in hopper 72 to remove the moisture therefrom.
The gate 74 ~ s ralded and the control 58 set to cause the
thrower 44 to operate at the selected speed most suitable for
the particular conditions, ~hen teeming o~ the hot metal
starts the control 70 is operated to cause the ~eeder 62 to
feed the scrap at the desired rate ~pounds psr min.) to the
thrower 44 so that it is ~ed along with the molten metal into
the selected mold 38. In case the ~eed of the molten metal is
stopped for any reason~ feed of scrap is ~mmediately stopped
by operation o~ control 70. Throwing the scrap into the mold
at a relatively high speed insures that it will penetrate the
molten metal already ~n the mold rather than ~loating on top.
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The levers llfi and 132 may be operated during pouring to
change the angle of discharge of the scrap into the mold.
After the mold is filled flow Or hot metal and scrap is
stopped and the ladle Or hot metal and supporting structure
28 are moved into position to fill another mold 38 and the
process is repeated~ The hopper 72 may be made suf~iciently
large to contaln enough scrap for the entire charge in the
ladle or a plurality of replaceable hoppers 72 may be provided
with the scrap being heated in the ho~rs in another locatio~
It is then only necessary to replace an exhausted hopper with
a filled hopper. By filling the hopper with just enough scrap
to be fed to one mold the replacement can be made while movlng
the ladle and scrap feeder to another mold. Another manner of
operation is to heat the scrap at another location and pour
the heated scrap into hopper 72 on structure 28. When the
ingot mold is a continuous mold it w~ll usually be neces9ary
to have replaceable hoppers or means to heat the scrap at
another location for charging into the hopper. U1hile it is
desirable to feed the scrap uninterrupted, there is no loss
in quality e~rhen pouring of the hot metal proceeds without
~eeding of scrap. This~ however, reduces the percentage of
; scrap wh;ch can be added,
~ hile the scrap charger is shown mounted on wheels
supported on a platform, it will be understood that it could
be suspended from a crane or even be mounted stationary as
when feeding into a continuous mold.
Figure 7 shows a second type o~ apparatus suitable for
carrying out my invention which is less expensive than the
first type, but which is suitable for many p~poses,
especially in smaller shops. It is also suitable for
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carrying out experimental work to determine de~ign
characteristics for machines for a large shop~
In this embodiment a throwing mechanism 14l~j similar
to, but smaller thanJ throwing mechanism ~L~ mounted on a
supporting structure 146. A hydraulic power unit lLi8 is
mounted adjacent mechanism 1l~4 and the mechanism 1l~4 is
operated by a hydraulic motor 150 which drives pulley 152~ A
control 15~ starts and stops motor 150 and controls its speed
and hence the ~elocity o~ scrap f'ed to chute 156. A hopper
158 is mounted on structure 1~6 above hopper 160 of throwing
mechanism 144 . Heating elements 162 are provided around the
outside of hopper 158 as in the second embodiment~
The bottom o~ hopper 158 is provided with a closure
16ll which is pivotally mounted at 166 and is movable between
open and closed positions by means of lever arm 16~ which is
pivotally mounted at 170. A link 172 has its ends pivotally
connected to closure 164 and le~er arm 168. The lever arm
168 may be ~rictionally held in adjusted position or other
mean~ such as a pin and holes may be provided ~or this pur-
pose. The top o~ hopper 158 is provided with a plurality ofcompartments 174. A pivotally mounted gate 176 is provided
at the bottom o~ each compartment 174 and is movable by a
lever arm 178 connected to link 1~0 whlch in turn is connected
to gate 176 by wire rope 182~ Lever arm is locked in position
by bracket 184,
In operation, the assembly is positioned in the desired
location in any suitable manner. Scrap is loaded lnto one or
more o~ the Gompartments 174 and/or in the main portion of the
bin 158. The amount of scrap in each compartment and main
portion of the bin is weighed. prior to loading~ In carrying
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out experimental work to determine how much scrap 3hould be
added to a particular casting the amount can be ~aried ~rom
a small amount in the main portion of the bin to an amount
which completely ~ills the bin including the compartments 174i
Assuming that the maximum amount is to be added the chute 1~6
is positioned to discharge scrap into the mold and the control
154 i~ actuated to cause the throw~ng mechanism 141~ to throw
scrap at the desired velocity, The closure 164 is then opened
to discharge the scrap ~rom the main portion o~ hopper 158
into hopper 160 a~ter whlch it may be closed and the gate 176
of the compartments opened to discharge its scrap into the
main portion of the hopper. lPlhen the initial scrap ha~ been
thrown from the throwing mechanism 144 the operator open~
closure 164. This is repeated until all the scrap has been
fed to the mold~ In some instances the closure 164 may remain
open and the 9 crap from each compartment ~ed directly into
hopper 160. It will be seen that the operator controls the
rate of feed by opening the gates 176 at desired intervals. .
It will be understood that the operation o~ each
a~sembly will be substantially the same regardless o~ whether
the molten metal container is a ladle or a furnace and the
receiver is a mold or a ladle.
In carrying out one species of my invention? a heat
of molten metal o~ the desired composition i9 selected and
scrap ha~ing an analysis approaching that o~ the molten metal
i8 provided~. Since the invention is particularly suitable
and desirable for making rolled steel products~ the molten
metal i~ preferably pro~ided from a low carbon aluminum-
killed teel heat which has a finishing bath temperature
between 2860 and 2880F, and a ladle te~perature between
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2845 and 2865~ V~ile it is preferable that the scrap
analysis be tho same as that of the hot metal, the in~ention
~ay be practiced b~T using scrap o~ a~ analysis that differs
somewhat from that of the ~ot metal as long as the scrap has
similar physical properties as the steel of the heat. The
scrap has similar physical properties as the steel of the
heat. The scrap is cut into relatively small pieces~ For
example, pieces 2 ~nches x 2 inches x .o24 inch thick are
suitable The scrap must be cleaned before use to remove all
o~ the oil, grease, dlrt and rust therefrom. To insure that
all the moisture is removed in a relatively ~hort time, the
scrap is preferably heated to a temperature between 400 and
500F, The scrap and molten metal are ~ed to the mold
simultaneousl~J through the closed chute at a controlled rats
and ~peed such that the velocity of the pieces is suf~icient
to enable penetration of the molten metal in the mold! This
enables better distribution of the pîeces of scrap so that a
larger amount of ~crap may be added and a more uniform product
obtained.
The percentage o~ scrap may vary~ but to enable a
large amount of æcrap to be used it is not intended that the
scrap melt~ l~hile ob~iously there will be some meltlng of
the scrap, the ma~ority thereof will not melt, but will be
completely encased in the molten steel as it solidifies in
2~ the mold.
~hen using 24 inch x 37 inch x 85 inch molds~ 1,330
pounds o~ scrap may be added to 14 ,670 pounds of molten steel
so that the scrap is 8.3~ o~ the total weight of the ingot or
2,600 pounds of scrap may be added so that the scrap is 16.~
of the total weight of the ingot, In the ~irst instance, the
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scrap is added at a steady rate for a total period o~ 30
seconds and in the second insta~lce, ~or a total period o~
25 seconds. ~he ~mount of scrap added should be a minimum
of ~0 o~ the total weight o~ the ingot, but may be as high
as 50%.
The steel is then permitted to solidify 9u~ficiently
to handle~ removed from the mold~ and placed in a 90aking pit
to heat it throughout to its rolling temperature and then
rolled into slabs in the usual manner. During this rolling
operation in ~ich the cross section is reduced a minimum o~
75a~0 the pieces o~ scrap are pressure welded and bonded to
each other and to the steel o~ the heat. The slabs are then
heated and rolled into other products~ such as hot rolled
sheet steel, in the usual manner. The resulting steel product
has sur~ace characteristics and physical properties making it
suitable ror a wide range o~ end uses.
I have found that sheet steel scrap material having a
maximum thickne~s o~ .25 inches, a minimum dimension of one
inch, and a maximum dimension of ~our inches is particularly
suitable, This sheet material includes hot and cold rolled
sheet and strip and black plate. It is also pre~erred that
the piece~ be of substantially uniform size. If other types
o~ scrap are used, the maximum dimension should preferably
not exceed ~our inches. It appears that scrap additions
under lOa~ may not be economically justi~ied. ~ercentage
additions over 2 ~ may require heating of the scrap to
temperatures substantially abo~e 500F and create problems
in handling and adding the scrap to the molten steel.
I have ~ound that the rolled steel product~ especially
in sheet ~orm, consists o~ a mass of steel having a plurality
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0~ 9~11 steel scrap piece~ intersper~ed ln and bonded
thereto. ~ecause of the scrap addition~, there ls random
grain or~entation The physical properties o~ the product
are comparable to those of similar conventional steel products.
Since the above procsss requires that the casting be
rolled to insure that the pieces of scrap be weldsd into the
~ass of metal it cannot be used to make a casting ~n ~lnlshea
~orm except for ma¢hining. ~owever, by modi~ying the above
process by limiting the amount o~ scrap to that which can be
melted by the molten metal a homegeneous mixture is obtained.
In thi~ case the ~crap need not be o~ an anal~Jsis approaching
that of the molten metal, but must be known so that the
product will have a known analysis. In fact, the 9 crap may
be selected to ~ary the analyses of the metal product. Whils
this modification cannot utilize as much scrap as the first
described method9 it does have the ad~antage that the product
cannot be di~tin~uished ~rom a conventionally produced product
and can be used to procluce an~ conventional end product.
In a third embodiment o~ my invention, the 9 crap is
~ed to a ladle 3imultaneously with molten metal ~rom a ~urnace
in the same manner as described above. As in the second
embodiment the scrap need not be of the substantially same
analysis a~ the molten metal and must melt in the receivsr.
In fact in some instances it may be selected to modify the
analysis of the resulting mixture. For exampleJ ln making
steel the ¢arbon content o~ the qcrap may be higher or lower
than that o~ the molten metal to raise or lower the carbon
content of the mixture. If the molten metal is iron, rather
than steel, which is to be used in making an iron cast~ng,
steel 3crap may be added~ This method has the sams
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ad~antages as that Or the second embodiment, In add~tion
it can be used to lover the temperature of the molten metal
to that most suitable ~or pourin~ when such is necessary,
thus replacing presentl-J used methods of accomplishing this.
As a resul~, increased production is obtained with min~mum
added cost. In some in~tances the temperature of the molten
metal may be raised intentionally at relativel~ little cost
to enable a larger percentage o~ scrap to be added. ~hile
the amount o~ added scrap may vary considerably depending
upon the type o~ metal, the temperature o~ the b~th, etc~
it i3 doubt~ul that more than 1 ~ by ~elght o~ scrap can be
added and in most instances would be limited to approximately
2 to 5%.
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