CA1041769A - Porous ferrous metal impregnated with magnesium metal - Google Patents

Abstract

POROUS FERROUS METAL IMPREGNATED
WITH MAGNESIUM METAL

ABSTRACT OF THE DISCLOSURE
A composition of matter comprising a mass of ferrous scrap pieces compressed together in random orientation forming a net-work of interlocking pieces has been prepared. The ferrous metal network has a density of 1.2 to 4.0 g/cc, a porosity of 50% to 85% and a short transverse tensile strength (S.T.T.S.) of at least 2 psi, preferably at least 2.5 psi.
This ferrous metal network may be impregnated with magne-sium in amount from 18% to 55% by weight of the impregnated body.
The magnesium impregnated body is useful for treating high melt-ing metals such as ferrous metal to reduce the sulphur content or to produce nodular iron.

Description

BACI~CROUND OF TI~IE ~N
n the iron and steel industry, it -s ~ ~ow~A~ e ~ z !~

as the 30 ~ lmpregnated . nder these cond t ..

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1 the violence is hcld to minimum.2 Among thc known porous bodies which have been used with 3 limited success for this purpose are porous coke, carbon, graphite 4' and ceramic bodies such as quicklime, lump limestone or dolomite 5j, and the like.
. .
6i In addition, magnesium has been infiltrated into porous 7li iron bodies. Among these prior art iron bodies is sponge iron 8 " in which the iron particles are very small and are sintered to-g `, gether to form a porous structure. Sponge iron itself is expen-lO ,I sive to produce and to use. The cost o-E forming large porous 11 1' structures from sponge iron is also an expensive procedure.
1~ I Since the pores of the sponge iron are excessively small ;~
13 ! they tend to release the magnesium too slowly when immersed into 14 l~ the molten iron and the release may be too quiescent for optimum 15 il operation. Sponge iron also may contain oxides which may form a 16 ,~ violent reaction with the magnesium which may also impair the ~ -;
17 1! efficiency~
18 ,' Another method used by the prior art to produce iron bri-19 ¦I quettes containing magnesium is to dry press together iron parti-20 ii cles and magnesium particles bo~h of which preferably are from 21 j' 4-60 mesh.
22 1I When these compressed iron and magnesium particles are used 23 lj to desulfurize molten iron, the remaining iron structure becomes 24 ll decidedly weak as the magnesium melts and there~ore the magne-25 '' sium may be released too quickly and there~ore may cause a vio-26 i lent reaction.
27 ll In contrast to these prior art products, the instant inven- i~
28 ` tion prepares a network of ferrous metal pieces, particularly 29 ' steel turnings, compressed togethcr which forms a body having a -~
3O , low density, high porosity and high strength which may be

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~4~L76;~9 infiltratccl with largc quantitics o~ magn~sium mctal.
The voi~ls in the metal network are sufficiently large to release tllc magnesium at a desirable rate, i. e., fast enough to provide ra~i(l trcatment but not too fast so that the treat-ment is unduly violent.
It has bcen found that the porous ferrous metal network of the instant invention possesses advantages which are not present in the prior art porous bodies.
SUMMARY OF TIIE INVENTION ;;. . .
According to one aspect of the invention there is provided :
a mass of ferrous metal scrap pieces of random sizes compressed to~et~ler in a hapllazard ordcr forming a metal networ~ of inter- -locking pieces, the voids between said pieces forming a labyrinth of interstices tl-rougl-out s~id networ~, said mass having a ~ensit~
of from l.~ to ~.0 glcc. the intClSticCS in said net~ork formin~ -a porosity of flom 500 to ~50, sai~ metal network ha~ing a short transverse tensile strength of at least 2 psi.
According to another aspect of the invention there is pro~
vided a composition of matter comprising a mass of ferrous metal ~ . .
pieces and magnesium, said~scrap pieces being of random sizes compressed together in a haphazard order forming a metal ne~work :
of interlocking pieces and voids between said pieces forming a labyrinth of interstices throughout said network, said :,letal network having a density of from 1.2 to 4.0 g/cc, the interstices in said network forming a porosity of from 50~ to 85~o ~ said metal network having a short transverse tensile strength of at least i psi, said magnesium filling said interstices, the amount of magnes-ium in said interstices being from 18~ to s5O by weight of the total wei~ht of said metal network containing the magnesium.
According to anOther aspect of the invention there is pro-vided a process for producing a porous ferrous metal network impreg-,~

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~L~J41q~9 nate~ with mllgncsium which compriscs sclecting ferrous metal scrap pieces which have a densi~y of 0.1 to 1.0 g/cc, compacting said pi~ces into a mctal network having a ~nsity from 1.2 to 4.0 g/cc, ~ porosity of 50~ to 85~ and a short transvcrse tensile strength of at least 2 psi, immersing sai~ metal network into a molten bath of magnesium to impregnate said network with said magnesium, the impregnated metal network containing from 18% to 55% by w~ight of the impregnate~ network and removing said impregnated networX from said molten magnesium. '-Accordiny to yet another aspect of the invention there is provided a process for producing a porous ferrous metal network impregnated with magnesium which comprises selecting ferrous metal scrap pieces which have a density of from 0.1 to 1.0 g/cc, said scrap metal pieces having an oil coating on their surfaces, compacting said pieces into a metal network having a density of from 1.2 to 4.0 g/cc, preheating said metal network at a tem- -perature from 5000F to 12000F to burn off the oil, and immersing said network into a molten bath of magnesium to impregnate the metal network with from 18% to 55~ of magnesium by weight, based on the total weight of the impregnated network and removing said impregnated network from said molten magnesium.
Preferably the strength of the compressed composition of matter of the invention is at least 2.5 psi.
The porous ferrous metal network impregnated with magnesium is useful for treating ferrous melts, for example, for desulfur- ' izing the melts and also for producing nodular iron. Normally -about 3/4 to 1-1/2 pounds of magnesium metal are used to de- , - sulfurize 1 ton of molten iron. About 2 to 4 more pounds of magnesium are used to form one ton of nodular iron.
DESCRIPTION OF THE P~EFERRED EMBODIMENTS
This composition of matter is produced by selecting scrap - 3a -~ o~L7~9 ~:

l metal pieces particullrly ste~el turnings which Eall within the ~ -2 following size ranges:
' length 1/8 to 9 inches width 1/64 to 1 inch

4,I thickness 1 to lOO mils

5 ii Scrap mctal pieces within this size range usually have a ~' bulk density of from 0.1 to 1.0 g/cc.
7 ii These metal pieces are then compressed at pressures from 8Il 0.5 to 8 ~si and they form a ferrous metal network having a den-9~I sity of from 1.2 to 4.0 g/cc. As stated previously the porosity 10I, of the network is 50% to 85~ and it has a short transverse tensile ll ~ strength of at least 2 psi.
12 l¦ This fcrrous metal network is then immersed in-to molten mag-13Ij nesium metal and held in the molten metal for a few minutes to I `
14~I impregnate the in~erstices of the métal network. The impregnated I `
15~¦body is removed from the molten magnesium and it is cooled to 16 1¦ solidify the molten magnesium.
17 1l The impregnated metal is cooled, pre-ferably in the absence 18 il of an oxidizing atmosphere. One preferred method of cooling the l9I¦ impregnated compressed metal body~ is to immerse the impregnated 20!¦body into an oil bath. -21il The final product comprises a porous composition of matter 22 !I comprising a compacted metal network impregnated with magnesium 23¦jmetal. The composition contains at least 18% magnesium metal by 24 iI weight of the total impregnated metal body.
25., The porous ferrous metal network composition o-f the instant ` ;-26 'invention when impregnated with magnesium is superior to the porou$ ~
,; . , . - . . .
27 Ibodies of the prior art. The instant porous body not only may tak~
28 !~ Up and retain magnesium in amounts greater than about 18~ of its 29!itotal weight, but in addition, when used to desulfurize iron, the i 3ljporous body releases the magnesium metal over a short period o-f I ;
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Il . . -. -7~9 l -time without crcating a violent reaction. It also has a struc-2 l tural strength l~hich ls retained as thc magnesium is being re- ;
3 lcased. This is advantageous since the maintenance of the struc `
4 ll tural strength is necessary to prevent a violent reaction from 5 1! taking place since the magnesium is released in a controlled man-~¦1 ner. In addition it is also advantageous to employ this parti-71I cular type of magncsium infiltrated porous body over other types 8 1 of magnesium impregnated bodies since the residual ferrous metal g!! in the porous body may be dissolved in the molten metal without ¦
lo!~ having to remove the residual carrier. It has also been found ¦ that this particular type of ferrous metal body possesses suffi-12j`l cient strength to withstand handling prior to in-filtration, while 13 li at the same time possesses a porosity which will hold an amount I ,~
14~ of magnesium metal of at least 18%. -15~ In addition to produci?lg a product which h~s all o-E these 161 advantages, the porous body of the instant material may be made 17 ll with raw materials,which are readily available. I
18I¦ The density of the compacted ferrous metal network before 191¦ impregnation is from 1.2 to 4.0 g/cc, while the density of the 20 ~ scrap metal pieces before compaction was 0.1 to l.0 g/cc. Metal 21¦ porous bodies containing amounts o-f magnesium metal from 18% to 22 li 55% may be produced by this process. Reproducible products are 23 ¦¦ also readily obtained.
241l If the density o-E the compressed -ferrous metal network is 25 1I below 1.2 g/cc, the amount of magnesium which will in-Eiltrate the ¦
2~l' compressed metal body will be above 55% by weight. At -this upper l 27 1l weight limit the volume of magnesium will occupy 85% of the total ., 28 ! volume of the infiltTated compressed metal body. W~h more mag-29 ¦ nesium in the infiltrated body, when used to desul-furize iron, 3o ~ the metal body will be structurally very weak as the magnesium _5_ 1 ~:

~4 ~7 l is dissolved in the moltcn iron and ~he reaction will become 2 ~ too violent. -3 ~ If the density of the compressed ferrous metal ~ody is 4 i! above 4.0 g/cc, the amoun-t of magnesium which will infiltrate the !
51~ compressed body will be below 18% by weight. When the magnesium 61 content is below l8~, the amount of magnesium per unit weight 7j of scrap metal is too low and there~ore results in an uneconomical ~l operation. In addition if an excessive amount of scrap metal is gi added with the magnesium to the molten iron, the excess scrap lOI metal may also chill the molten metal excessively. This cooling I ;
ll¦ effect is to be avoided.
12! If the scrap pieces are too coarse and/or too dense, the 13 briquettes will not hold toge~her at the low fabrication pres- ~
14 Isures used. If high fabricated pressures are used, the briquette I -will not have sufficient porosity to be infiltrated with a su~-16 ficient amount of magnesium.
171 The scrap metal pieces useful in the instant invention in- J
181 clude ductile iron and the like but more preferably steel. The l9¦ scrap metal pieces as previously stated must -fall within the size - ~201 ranges specified above. If the scrap pieces used are too short~ 1`!,.' '., '211 too thick, too wide or too flat, excessively high pressures would 22 ¦ have to be used to obtain the structural strength necessary and 23 ¦¦therefore the compressed body would be excessively dense which ~
24 l~would result in low percentages of magnesium infiltration. x 25 11 The most desirable type of scrap metal are those which are 26 ¦1 irregular in shape cmd have a variety of sizes which fall within 27, the sizes specified. Fine metal turnings, short shovelings and ~ ~-28 ¦¦ the like are the most desirable.
29 ¦¦ The compacted metal porous bodies prepared in the instant 3 ~invention also may be impregnated with alloys. Alloys particularl 7 ! ` 6 .
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l ,clesirable to use are magncsium alloys containing alkaline earth 2 inletals, aluminllm, silicon and rare earth metals such as cerium, 3 l lanthanum, or rare earth alloys, such as "Misch Metall" and mix-¦ tures of these metals. The term "magnesium" hereinafter referred 5 ¦¦ to is meant to include magnesium metal and alloys of magnesium 61 metal.
7 The magnesium infiltrated compacted porous steel network 8 structure produced in the instant invention possesses the -follow- ll 9 ing combined advantages over the prlor art: ¦
1) have high poroslty and therefore are capable of ¦ ~
11 retaining large quantlties of magnesium metal; ¦ ~ -12 2~ the impregnated bodies produced are structurally 13 strong and capable of withstanding high temperatures 1 "~
14 until the magnesium has been released during subsequent treatment o-f molten iron.
16 3) the impregnated bodies produced are active when intro-17 duced into molten iron, thus capable o-f desulurizing 18 Tapidly the molten iron without producing violent 19 reactions. Reaction times to release the magnesium metal from the impregnated bodies may range -from 1/2 21 to 10 mlnutes.
22 4) the magnesium infiltrated bodies made by the instant 23 invention are uniform in compositlon and when they 24 are used to treat molten iron, reproducible result~
are obtained.
2~ 5) the addition o-f the particular type o~ magnesium 27 impregnated body employs iron or steel as the carrier 28 and there-fore does not introduce foreign carrlers to 29 the molten lron which subsequently would have to be 3o removed from the molt n iron.
. 1.

1' 6) the scrap metal may melt after the magnesium has been 2l released thus contributing iron to the mel~ and ' 3l eliminating the necessity of removing the carrier - ' 4 !l, a-fter the treatment. I "
5 I Scrap metal generally contains a coating o-f oil. This I '~

6 I coating may be removed before infi:Ltration, i-f desired. One

7 I method of degreasin~is by heating the scrap to burn off the

8~l oil. This heating may be done'be-fore or after compressing. It 9Ij is economically advantageous, however, to compress the scrap lO¦I metal then heat the compressed metal to remove the oil and to pre-¦
Il . I .;........................................................... .
~ heat the metal at the same time beEore it is introduced into the 12 ¦j molten magnesium for infiltration.
13 ll If the compressed metal is preheated before introduction 'l -14 into molten magnesium, care should be taken to prevent the scrap ¦ ' 15 ' metal from oxidizing exces'sively. The oxide present can react ¦ ;' ' i . ....
16 I with magnesium metal and may contribute to the violence during - -17 ¦ the subsequent treatment of the ferrous melts and may consume a ;
18 I significant amount of magnesium, thus lowering the efficiency. I -19 ! It has been -four,d that the weight gain of the scrap metal I ` '''~
20 ¦ compressed network due to oxidation should not exceed about 3% ' 21 ¦l~ and preferably not exceed about 1% during the preheating step.
22 The amount of oxida~ion may be held within the limits 23 speci:Eied if the preheating temperature in air is held between 24 about 500F and 1000F. Temperatures up to about 1200F may ¦ *};
25 l also be employed if the time of preheating is held to no more 26 ¦ than about 1 hour.
27 l Obviously the preheating temperature upper limits are not ~
28 ~ crltical i-f the preheating is carried out in a non-oxid~zing '' ' 29 ll ~ atmosphere.
3 ~¦ Care should a'lso be taken in the storage of the magnesium ;
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- 1 infiltra~cd I~o~Iies to avoicl reac-tion of the magnesium l~ith mois-2 ture. Tllis may be reaclily accomplisIlecl by sealing the infil-3 trated bodics in a s~ able container or placing the infiltrated 4I; bodics with a drying agen-t in a metal can having a tight fitting 5I; lid.
The following ex~aples are ill~lstrative o~ certain -.
prefered embodimen~s and are not intended to limit the invention -as claimed.
8 !, E X A M P L E
. . . _ : .
gj Fine steel turnings about 2 mils thick, 1/8 inch wide and l inch long were degreased with a chlorinated solvent. The degreased turnings had a density of 0.17 g/cc.
12 I, 57 grams of the degreased turnings were dried and inserted 13, in a compaction chamber (1-3/4 inch diameter x 3 inches high~.
14 ~ The turnings were compacted at 1 tsi to produce a briquette 15 IIl 7/8 inch diameter x 0.7 inch high. The density of the briquette 16 Iwas 1/8 g/cc. The compacted briquette was preheated to 8soF for 17 '1 hour to remove the residual solvent. The amount of oxidation 18 during the preheating step was less then 1~.
19 I, The briquette was then immersed in molten magnesium at 20 '1350F for 5 minutes. ~fter the infiltrated briquette was removed 21 i'from the molten magnesium and cooled, the briquette was reweighed. ~;
22 I,It was found to weigh 102 grams and contained 44~ magnesium 23 Imetal by weight. The briquet~es short transverse tensile strength 24 Ii~S.T.T.S.) before magnesium infiltration was 3.3 psi.
25 !l The operational details and the results obtained are recorded 26 in Table 1.
27 il E X A M P L E 2 . _ ........ ... _ :
28 ! The infiltrated briquette prepared in Example 1 and another 29 briquette prepared in the same manner were used to desulfurize 3o ~olten iron.

~04~7~9 l 'I'hcse two briqucttes w~rc plac~d in a plunging bcll which 2 was insertcd into a 400 pou]ld m~lt Or iron at 26sooF. The 3,-magnesium infiltrated into thi~ briquettes was released at a ..
4l,moderate rate without violcnce or melt spillage in spite of the I ~
5 1l high concentration of magnesium (78 volume %). .:
61; Tl~e amount of sulfur in the molten iron was reduced -from .i 7'Ø041~ to 0.013%. `~
8 ¦i The details of opera~ion of the desulfurizing process ~
g¦lare recorded in Table 2. 1 -lO~, E X A M P L E 3 In this example steel turnings 5 to 10 mils thick, 1/8 to 12 ¦l 1/2 inch wide and about 1 inch long were employed. The bulk , .
13 ¦density of this scrap was 0.57 gm/cc. The procedure described . : ;~
14 lin Example l was used except that a 3 inch diameter ~riqwette was ' `
15 ,produced in Example 3 with a compaction pressure of 4.2 tsi in~
16¦1stead of 1Ø The compressed briquette was heated at 850~.for 17l¦1 hour to burn off the oil.
18l1 The operational details and results obtained are recorded l9 in Table 1. ¦ :
20 ! E X A M P L E 4 , ~ .
21,1 In this example the briquette prepared in Example 3 was ... :
22 ,used to desulfurize iron. The method used -for desulfurizing the ' `.-23 li iron was the same as that described in Example 2. 1 -24 j! The operational details are described in Table 2. 1 , .
25~1 E X A M P L B 5 ;, .
26', This example is presented to show the preparation of bri-27 ¦~uettes in a manner similar to Example 3 except that the scrap 28 steel was not totally degreascd before infiltration with the ~9 magnesium.
3o . 406 gms. of scrap 5 to 20 mils tllick, 1/16 to 3/8 inches , -10-' 1''~
.
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wide, and al~ou-t ] inch long werc place~l in a die 3" in cliallleter 2 an(l 6" decp. l\ pressure of 2.~ ~si was applicd to the scrap by 3 mc.lns of a ram. A bri~luette was formed mcasuring 3-1/8" in 4, diamcter and 1 . 06 inch thick and had a density of 3. 04 g/cc .
5 ' The briquette was submerged into the molten magnesium for 6 1l about 10 minutes and removed. 110 gms. of magnesium had infil-7 'i trated the briquette and it contained 21.7% magnesium.
~ li The operational details are recorded in Table 1.

9 ,, E X A M P L E 6

10 l¦ Thls example is presented to show the making of a briquette ll similar to the procedure described in Example 3 except that the 12 ~1 briquettes were not preheated before being immersed into the 13 j l mo l ten magne s ium . , 14 1' Steel turnings 5 to 20 mils thick, 1/16 to 3/8 inch wide 15 l! and about 1 inch long were degreased by trichloroethylene in a 16 ,, vapor degreaser. 395 gms. of degreased scrap were placed in a 17 ~, die 3" in diameter and 6" high. A pressure o-f 2 . 0 tsi was applied 18 I to the scrap producing a briquette 3" in diameter and 1" thick. I
l9 ll The briquette had a density of 3 . 4 g/cc.
20 1, The briquette at room temperature was immersed into molten 21 j1magnesium for about 10 minutes which was maintained at 1400F-22 i After removing the briquette from the molten magnesium, it weighed 23 I, 505 gms. and contained 21. 7% magnesium.
24 1 ~ The operational details are recorded in Table 1.
, 25, E X A M P L E 7 26, In this example a briquette was produced as in Example 1 27 except that a compaction pressure of 2. 5 f~si was used.
28 ,! 47 . 3 gms . of degreased fine s~eel turnings were placed in 29 1 a die 1-3/4 inches in diameter and 3 inches high. After compac-30 I tion the briquette had a diameter of 1-3/4 inches and was .60 inch, 31 ¦Ithick and had a density of 2 . 4 gms . /cc .
1, -1~ - ' ' ' Il . , .

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~ q 69 1 Aftcr prellea-tillg thc briquette to 850r: Eor 1 hour, it 2 was immcrscd into molten magnesiulll and removed. The infil~rated 3l briquette wc;ghed 65.7 gms. and contained 31% magnesium, 4 ' The operational cletails are recorded in 1'able 1.

6,' In this example a briquette was prepared in a manner as 7 ,described in Example 1 except that a compaction pressure of ' 8 !10-7 tsi was used.
9 ll 8.14 gms. of degreased steel turnings were placed in a lO ~Idie 1-3/4" in diamcter and 3" high. A pressure of 0.7 ~si was

11 ' exerted on the scrap which formed a briquette 1-3/4" in diameter ~2 iil and .211~ high with a density of 1.5 gm./cc.
13 li The compacted briquette was then heated to 850~ for one 14 ,',hour to degrease it. After degreasing the compacted briquette 15 ~ was infiltrated with magnesium by immersing it in molten mag-16 I'nesium. The lnfiltrated briquette weighed 17.5 gms. and was 17 jj53.5% by weight magnesium, 18 ¦l The operational details are recorded in Table 1. ; , 19 1! E X A M P L E 9 `~
20 1! A briquette in this example was prepared in a manner similar 21 ito the procedure described in Example 3 except that a briquette 22 '5-7/8" in diameter was made.
23 2270 gms. of steel turnings 5 to 10 mils thick, 1/8 to 1/2 24 inch wide and about 1 inch long were placed in a die cavity cylind- ¦~
er 5-7/8" in diameter. The briquette was 1-5/8 inch thick. A pres-26 lsure o~ 3.5 tsi was used. The briquette was then heated to de-27 ~grease it. The degreased briquette~ which weighed 2180 gms., was ~`
28 linfiltrated by immersing it into molten magnesium. The infiltrated 29 ,briquette was 25% magnesium and weighed 2920 gms. '!, ~, The operational details are recorded in Table 1.

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~ 7 ~ 9 l ~s ~1cseri1)e~1 ahovc the magncsiull1 inifiltr~lted briquctte of 2 scrap iron have been used to desulfurize molten iron. In addi-3 tion these briquettes are also useEul or making nodular iron.
4 The method is described in the following example: i 5` E X A M P L E 10 6, In this example briquettes as prepared in Bxample 3 were 7 used to nodularize iron. 400 lbs. of iron were heated to temper-8j atures of 264ooF. Initially the iron contained .028% by weight 9 ; of sulphur and no magnesium. By means of a plunging bell, 1797 lO, gms. of the briquettes describecl above were added to the molten ., .. ~ .
ll iron. The briquettes contained 395.34 gms. of magnesium per ton

12 o-f iron or .2177% by weight.

13 I By observing the amount of time that flaring occurred on

14 ;the surface of the molten iron, it was determined that the magne-

15 I sium had reacted completely in 3 minutes from the time of plung-

16 ing. A sample of the nodularized iron was taken and the bell was

17 1 ~emoved. The magnesium content of the nodularized iron was .052%

18 l by weight and the sulphur content had been reduced to .007% by l9 weight.
20 ~ It was also determined that a sand casting of the nodular 21 iron had the following mechanical properties:
22 Tensile strength 65,400 psi 23 ,, Yield strength 39,500 psi i ;
24 Elongation 14%
As previously stated the scrap metal pieces must be of size 26 'which falls within the limits specified above in order to obtain 27 ;~a network of interlocking pieces which has a porosity o-E 50% to 28 1 85% and a short transverse tensile strength of at least 2 psi.
29 11 Example ll is presented to show the use of scrap metal 30 ' pieces which are of size which falls within the specified limits. ;
31 '! ~xample 12 shows the use of scrap metal pieces which are o:E size 32 which fall outside the specified limits.
, -~3-l l. X A M P 1. E 11 2 In this exampLe 393 gms. of scrap steel pieces 5 to 10 mils -~
3 thick, l/8 to 1/2 inch wide and about 1 inch long were placed in 4 a die 3 inches in diameter and 6 inches high.
5 ¦1 A -force of 3.5 tsi was exerted on the scrap producing a 6 !1' briquette ~ inches in diameter and .97 inches thick. The 7l compacted briquette had a density of 3.I7 gm./cc and a porosity ;
~,;of 59.7%.
I; ~., g A short transverse tensile strength was determined to be lO ¦ greater than 5.2 psi.
ll i E X A M P L E 12 12 l' In this example 86.7 gms. of cast iron borings (-10~200 mesh) - ;
13 ''were placed in a die 1 3/4 inches în diameter. A pressure of 6.25 ~, 14 l'tsi was exerted on the borings. A briquette 1-3/4 inches and 0.6 ! ~.
15 'inches thick was formed. This briquette crumbled with only slight l6 i,handling and was too weak to test for tensile strength.
17 li From these two examples, it is apparent that the tensile 18 '~strength of the metal network is unsatisfactory when metal pieces l9 llof size below the lower limits are used. In addition it should 20 ~be noted khat the specified sizes and shapes of the scrap pieces 21 llenables the fabrication of briquettes of high strength at lower 22 ''compaction pressures. - I -23 il E X A M P L E 13 24 , In this example scrap steel turnings similar to those de- r 25 ',scribed in the previous examples were used.
26 The scrap steel turnings weighing 22.4 pounds were placed 27 I'in a ring shaped die measuring lS inches outside diameter x 5 inch-28 'es inside diameter x 6 inches thick. These turnings were then com-29 'jpressed at a load of 1000 tons maximum ~6.4 tons/s~.in.) to pro-3O l,duce a metal network measuring 15 inches outside diameter x 5 inches 1, il ' - 1~- .. .
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l' inside diame-ter x 1~2 inches thick. This compressed network was 2" ~legreased in an ovell at 1000 F ancl l~as impregnated with magnesium 3l, metal by inser~ing the metal network in molten magnesium metal.
4, The impregnated metal network contained 30%magnesium by weight.
5l' The density of the metal network before impregnation was 6~,3.29gms./cc and had a porosity of 58%.
7ll A plurality of these impregnated and compressed metal net-8l works was used successfully to desulfurize a batch of molten iron.

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Such a product is superior to prior art products when used to desulfurize molten iron or to produce nodular iron.

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While this invention has been described and .

illustrated by the examples shown, it is not intended to be strictly limited thereto, and other variations and modifications may be employed within the scope of the following claims.
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Claims (22)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A mass of ferrous metal scrap pieces of random sizes compressed together in a haphazard order forming a metal network of interlocking pieces, the voids between said pieces forming a labyrinth of interstices throughout said network, said mass having a density of from 1.2 to 4.0 g/cc, the interstices in said network forming a porosity of from 50%
to 85%, said metal network having a short transverse tensile strength of at least 2 psi.

2. Product according to claim 1 in which the ferrous metal scrap pieces in the network have individual sizes in which the length of the pieces is from 1/8 to 9 inches, the width is from 1/64 to 1 inch and the thickness is from 1 to 100 mils.

3. Product according to claim 1 in which the ferrous metal scrap pieces are steel scrap.

4. Product according to claim 1 in which the ferrous metal pieces are steel turnings.

5. A composition of matter comprising a mass of ferrous metal pieces and magnesium, said scrap pieces being of random sizes compressed together in a haphazard order forming a metal network of interlocking pieces and voids between said pieces forming a labyrinth of interstices throughout said network, said metal network having a density of from 1.2 to 4.0 g/cc, the interstices in said network forming a porosity of from 50% to 85%, said metal network having a short transverse tensile strength of at least 2 psi, said magnesium filling said interstices, the amount of magnesium in said interstices being from 18% to 55% by weight of the total weight of said metal network containing the magnesium.

6. Composition according to claim 5 in which said metal network is impregnated with magnesium metal.

7. Composition according to claim 5 in which said metal network is impregnated with a magnesium alloy.

8. Composition according to claim 5 in which the scrap pieces employed are scrap steel turnings.

9. Composition according to claim 5 in which the scrap pieces employed have individual sizes in which the length of the pieces is from 1/8 to 9 inches, the width is from 1/64 to 1 inch and the thickness is from 1 to 100 mils.

10. A process for producing a porous ferrous metal network impregnated with magnesium which comprises selecting ferrous metal scrap pieces which have a density of 0.1 to 1.0 g/cc, compacting said pieces into a metal network having a density from 1.2 to 4.0 g/cc, a porosity of 50% to 85% and a short transverse tensile strength of at least 2 psi, immersing said metal network into a molten bath of magnesium to impregnate said network with said magnesium, the impregnated metal network containing from 18% to 55% by weight of the impregnated network and removing said impregnated network from said molten magnesium.

11. Process according to claim 10 in which the ferrous metal pieces selected have lengths from 1/8 to 9 inches, widths from 1/64 to 1 inch and thicknesses from 1 to 100 mils.

12. Process according to claim 10 in which the ferrous metal scrap pieces contain an oil coating and that the oil coating is removed by heating the scrap pieces to burn off the oil.

13. A process for producing a porous ferrous metal network impregnated with magnesium which comprises selecting ferrous metal scrap pieces which have a density of from 0.1 to 1.0 g/cc, said scrap metal pieces having an oil coating on their surfaces, compacting said pieces into a metal network having a density of from 1.2 to 4.0 g/cc, preheating said metal network at a temperature from 500°F to 1200°F to burn off the oil, and immersing said network into a molten bath of magnesium to impregnate the metal network with from 18% to 55% of magnesium by weight, based on the total weight of the impregnated network and removing said impregnated network from said molten magnesium.

14) Process according to Claim 13 in which the weight gain due to oxidation of the metal network during the preheating step is held to no more than 3%.

15) Process according to Claim 13 in which the impregnated metal network is removed from the molten magnesium and immersed into an oil bath to cool said impregnated network, said cooled impreg-nated network when removed from said oil contains an oil coating to prevent oxidation of the impregnated magnesium.

16) Process according to Claim 13 in which a pressure of from 0.5 to 8.0 tsi is employed to form the metal network.

17) A composition of matter comprising a mass of scrap ferrous metal pieces and magnesium, said scrap pieces having individual sizes in which the length of the pieces is from one-eighth to 9 inches, the width is from one sixty-fourth to 1 inch and the thickness is from 1 to 100 mils, a mass of said scrap pieces having a bulk density before compression of from 0.1 to 1.0 g/cc, said scrap pieces compressed together in a haphazard order forming a metal network of interlocking pieces and voids between said pieces which forms a labyrinth of interstices throughout said network, said metal network having a density of from 1.2 to 4.0 g/cc, the interstices in said network before infiltration forming a porosity of from 50 to 85%, said metal network having a short transverse tensile strength of at least 2 psi, said magnesium filling said interstices, said magnesium being selected from the group consisting of magnesium metal and magnesium alloy, the amount of magnesium in said interstices being from 18 to 55% by weight of the total weight of said metal network containing the magnesium.

18) Composition according to claim 17 in which said metal net-work is impregnated with magnesium metal.

19) Composition according to claim 17 in which said metal network is impregnated with a magnesium alloy.

20) Composition according to claim 17 in which the scrap pieces employed are scrap steel turnings.

21) Composition according to claim 17 in which the ferrous metal scrap pieces are steel scrap.

22) Composition according to claim 17 in which the ferrous metal pieces are steel turnings.