US2241270A - Process for working iron carbon alloys - Google Patents

Description

May 6, 1941-. H. NIPPER 2,241,270

I PROCESS vFOR WORKING IRON CARBON ALLOY S Original Filed NW. 8, 1935 2 Sheets-Sheet 1 INVENTOR ATTORNEYS M y 1 H. NIPPER 2,241,270

PROCESS FOR WORKING IRON CARBON ALLOYS Original Filed Nov. 8, 1933 2 Sheets-Sheet 2 INVENTOR ATTORNEYS able iron have to a fartoo lowtemperatur'e which under certainga es is madepossible.

' out agreat number of are welded 1 further possible in Patented Mayo, 1941- UNITED-STATE s- PATENT OFFICE raocsss' roa womrmo mos cannon more Heinrich flipper,

The 'limken Roller Ohio, a corporation orchid;

Corporation, Rockford,

lilino and Stelium, Inc., corporation of Ohio Aachen, Germany, assignor to Bearing Comm Canton,

Gunitc Foundries 111., a corporation of Cleveland, Ohio, a

Original application November 8. 1933, Serial No.

897,188. 6, 1938, vember 8, 1932 Pig iron grey and white cast iron, and mallehitherto been regarded as being unworkable, either case of steel, it has been customary to reduce therolling temperature with increase of the failure to roll carbon'content one reason for the castv iron will presumably have to be attributed being employed, Comprehensive experiments of the inventor have shown that pig iron, grey and white cast iron andjmalleaible iron are readily workable, for example by-rolling, pressing, forging, hamcold or hot. Since, in the mering or drawing, etc, if, depending on the 'the material, temperatures, to the heat treatment of cast iron, are unusually high, for example from 950 up to about 1150 C. and above, are maintained.

In working up the material, castv ingots, billets composition of' which, in respect or plates of varying thickness, are heated uniformly to rolling temperature in heating furnaces and then rolled in rolling mills. The reduetion in cross-section, which on the average may amount to about 20% per pass, as well as the' frequency of reheating, thickness of-the rolled plates and profiles. The.

taining about Divided and this application August Serial No.'223,465. In Germany Nohere firmly together and cannot be separated from one another.

- Figures'l and 2 show the .compound material ,which has been so produced, at a. magnification of 100 and 250 respectively. Figure} shows a normal cast iron, containing about a silicon and 3% carbon, rolled out and cooled in air,

at a magnification of 250. Figure 4' shows a cast iron with a high content of carbon, con- 3.8% Cand'about 2.4% Si, after rolling and heating, at a magnification of 250.

Figure 5 shows a white cast iron,.low in silicon,

containing about $2% C and 0.5% 81, after rolling and cooling in air, at a magnification of 250.

Figure 6 shows a low carbon and 11181151110011- containing iron after rolling and subsequent annealing at a low temperature .to produce a ferritic matrix.- Figure 7 shows a material, which was rolled in the white initial state and anvaries with the small degree of brittlenessof the side edges,

circumstances may occur much cooling,' may be entirely the material in the last passes By doing so excessive starting material. may consist of cast iron plates, which are covered with steel plates and fore they are charged intosthe heating furnace. By this or any other 'suitable'manner, the conand rolling to smaller nealed after rolling to produce a. ferritic matrix. Figure 8 shows a material, which was rolled in the white initial state and after rolling was freed from carbon by heating in agents, which produce oxidizing gases, and was thus obtained in the ferritic state.

L All the figures show that graphite, temper carbon and also Ledeburite can be stretched to fibres in the direction of rolling. The materials produced have considerable strength and can also be joined with one another satisfactorily by soldering and welding, such as butt-welding." In

' the rolled cast irons the tensile strength was 6'7 k'gms/mii'i. after annealing. The rolled malle- ./mm. before annealing and 5a able iron showed a tensile strength of from up to kgmsJmm. with -5% elongation in the unannealed state. After annealing the same material showed a tensile strength of 50-60 kgmsJmm. with anelongation ofv 15-20%.

This is a division of my copending application,

Serial No. 697,138, filed November 8,1933.

The essential advantage of cast iron is that it can be easily melted and cast. In the case of to the steel plates at the edges betacting surfaces of 'the material are protected against the'influence of the furnace gases. It is by welding and diffusion of the carbon from the cast iron into the soft steel vmaterial, aplate ieonsisting halnand half of cast iron and steel,

or, alternatively, Least iron or, also,

two steel plates with a core of 'ings' of cast iron. The cast iron and steel adthe rolling to thus ,produce,

. temper carbon, increases.

sub-eutectic iron, the capability of being cast increases with the increasein carbon content. The capability of being rolled, however, gradually decreases as the content of hlghly carbon components, such' as ledeburite, graphite and It follows from this that for the production of rolled cast iron plates, an alloy is most desirable which does not have too high a content. of high carbon components to acore of steel with two cover,- I

permit 7 v rolling out has a. sumcient contentof suc components to permit satisfactory melting and casting. Accordingly, in the case of normal 2 unalloyed cast iron, which has been cast without special precautions as to solidification (chili mold, quenching, etc.) in normal sand (refractory) molds, the carbon content should be below about 3%. Cast iron alloys having a low content of carbon can be rolled 'more easily, but are more difilcult to cast. This, as well as the slight tendency .to become graphitized in'the cast or rolled state may be compensated by a high content of silicon or other elements.

The cast materiab may have various structures. With martensitic, troostic, sorbitic, pearl-,

one pass to the next, which, in turn, is dependent upon the composition of the material. when cooled down during rolling to a temperature of "about 900 0., it is advisable to reheat the ma-- shows high elasticity. It shows a very dense itic or ferritic matrix,-it may contain high carbon components such as cementite, ledeburite, graphite or temper carbon, in a more or less finely distributed, non-uniform or uniform arrangement. These high carbon components, dispersed in the matrix, can be given definite preferably fibrous form by the rolling operation. It is, howi ever, also possible, by subjecting 'an originally white cast iron or non-annealed malleable iron to heattreatment after the rolling only, to produce a normal stableorunstable temper carbon formation in any desired matrix. Steels containing free carbon in the form of graphite or temper carbon were never produced consistently,

so that a systematic production of graphitic line structure even of as little as a few tenths of one per cent of free carbon is in itself an important. feature of the present invention. White structure, since it possesses a sorbitic-troostitic, fine grained matrix, and graphite flakes finely distributed at right angles to the rolling plane or parallel thereto. Ifthe material is to be employed for special purposes, any desired hardness can be imparted to it by subsequent heat treat-' sheets made by rolling can be accomplished in different ways:

1. An' iron plate produced by rolling, of the v width of the circumference ofthe piston ring is cast iron can be readily rolled at a suitable temperature, and by subsequent treatment, plain malleabilizlng, or annealing "in decarburizing agents, it is= possible to produce black heart or European (white heart) malleable iron.

The material produced in this manner finds 7 application for many purposes. Piston rings may I be produced from sheets containing well-precipitated 'graphite by the method of stamping orby cutting off sections'of a. sheet which has previously been bent to tubular shape.

High quality piston rings are today manufactured by casting ;them individually in very accurate sand molds with a small allowance for machining. Since the small piston rings have only a small cross-section, it is necessary to allow but slight deviation with regard to chemical composition of the material as well. as with regard to the manner of melting and casting. I Only in this manner is it possible to manufacture bent up to a tube. and the individual piston rings are cut off from this tube.

2. .Strips of the final dimensions of the piston ring are cut out from the iron plate produced by rolling and then bent individually into the proper 3. Rings havingzthe iinal dimensions and final form are produced by stamping from an iron plate produced by rolling.

In this manner. piston rings of any desired dimensions and of high elasticity can be produced. Moreover, it is possible to impart, to the material of these rings any desired matrix, any content of carbon and any desired distribution thereof.

The piston rings may also be manufactured from the compound material consisting of cast iron and steel, which, has already been described. It is advantageous, in making the compound material for such ,rings, to unite the cast iron and steel in such a way that the cast iron in the finished ring will face the cylinder wall. The

steel, in such case. may be a normal or special steel, possessing highly elastic properties, causing wall.

piston rings which show a very. uniform sorbitic matrix and a uniform distribution of graphite.

The composition of the material and the structure of the piston rings have hitherto been governed by the dimensions of the piston rings. In'

with the present invention, a, high quality cast iron of a composition particularly suitable ,for

the purpose is melted in any suitable furnace.

and cast in a sand or a permanent mold into moderately thin plates of suitable length. After cooling or while-still hot from the casting operation,.this plate is charged into a reheating furnace and then rolled out tothe desired reduced thickness. The rolling process is advantageously started at temperatures between about 1000 and 1150" C. W

The number of passes depends on the degree The invention also contemplates the manufac l ture of bushingsand sleeves for contact with'moving parts such as the sleeves in the cylinder block of motors and engines, these parts being closely analogous to piston rings and. manufactured in the manner heretofore set forth with respect to piston rings. The method permits of themanufacture of these objects of improved characteristics due to the presence of graphite in the metal .and the'direction of the graphite grain produced in the rolling of the metal.

The materials produced according'to the invention are further suitable for brake drums and brake drum inserts subjected to great stresses.

Particularly brake drums and brake drum inserts can advantageously be made from the rolled graphite-containing material with a suitable matrix. For the same purpose, compound-rolled resembling the same. If, however, brake drums to which the material may be elongated from 78 made from steel are provided with a lining of cast iron, the brake drums become too heavy. This is brake the reason whya process for the manufacture of drums was introduced, consisting of cast iron being c cipies against moderately thin steel brake drums which are ofspeciai shape. These brake drums are of a very high quality. the thickness of the cast iron lining depending upon the necessary heat diffusion during the casting process. On the other hand, thismethod of making brake drums is exceedingly expensive.

The manufacture of the drums is in this case accomplished-in the iollowing manner. Steel and cast iron of particularly suitable composition are cast simultaneously in the same mold. A composite material oi the desired shape can also be made'by casting steel about a cast iron core, or by casting cast iron into a steel sheath and thereafter rolling the material. be made by rolling plates of cast iron and steel together into strips of the desired shape, welding during the rolling. In all cases the material can be shaped according to the cross-section of one or more brake drums. The strips are cut to the desired length, i. e. to a length corresponding to the circumference of the drum, and are then bent up in the colder hot state to rings and welded.

The brake drums, which are made according to the foregoing process, show the following advantages:

1. Since cast iron and steel are rolled simultaneously with one another, the materials are completely welded with one another and show an intimate joint. For this reason the brake drums produced are of high safety and low weight.

2. The process enables the best steel and the best cast iron composition to be employed for these special brake drums or shoes, the process being entirely different from those in which these brake drums are made by casting. In this process the composition of the material is not limited to the extent necessary in the manufacture of brake drums by casting.

' 3. Any desired shape and any desired crosssection of the material can easily be obtained with the aid of the rolling process.

Due to the satisfactory frictional properties of cast materials, in particular cast iron, slide ways and other members, which in use are subjected to frictional stresses, are advantageously made in accordance with the invention from east materials. For this purpose, certain analyses, for example,jiron-carbon alloys, with or without additions. of nickel, chromium, molybdenum, vanadium, etc'.,' and certain types of structures, for example. pearlitic, etc., are particularly desirable.

These slide ways and other members are first cast in suitable form, but are not employed in such form, but rolledattencasting or subjected to a drawing process or otherwise hot or cold worked, and in this way, brought into the form in which they are employed, aiter suitable surface or other treatment. T

fInorder to produce the desired structure in the finished product, for examp1e, -a predomihating pearlitic, sorbitic, martensitic or other suitable structurait may be advantageous arbitrarily to control the cooling of the piece, which maybe stillwarmfromthe rollingorbe again s ecially heated. for example, artificially. to retard'or to accelerate the cooling. Thismaybe accomplished by bringinsthe .into suitab y heatedrooms (e. g. iurnaces).byembedding the same in suitable substances which are good or in accordance with scientific prinr The material can'further bad conductors of heat. (c. g. powder), or bringing the same into homes, by quenching with the aid of sprayins or in any other-suitable manner.

The shaping of the slide ways is thus not obtained by casting in accordance with the desired pattern, but by rolling or subsequent working of a cast piece in a heated condition, appropriate duality of structure being imparted to the piece by a suitable treatment.

The processes herein described may also be advantageously employed for the production of transformer plates. bearings, checkered or corrugated plates, girders and. other structural shapes, grate bars, frame or casing parts for various machines and apparatus. sprinss, enamelling plates, material to be machined, cutting chisels, etc.

The term welding used in this specification in connection .with the production of compound: material is meant to cover all processes, which render it possible to unite the materials to be fused together in such a way that a permanent cohesion and a safe adhesion is obtained-which is able to resist the mechanical stresses, tending to separate .the plurality oi materials. merely. the separation itself will take place at the boundary line of the two diilerent materials. Normally one of the materials will rather be destroyed it separation is attempted. This is in particular the case in the combination 01 cast iron and steel. It welding has been effected satisfactorily a considerable difiusion of carbon from the cast iron into the steel takes place, whereby the adhesion oi'the two materials is so strong that if separation is attempted by force the cast iron breaks in itself, the separating surface being not exposed at all.

While I have thus explained the principles and have described and illustrated the preferred manner of utilizing my invention, I am aware that the invention may be otherwise practiced.

and I do not wish to be limited except as required bythe prior art and .the scope of the appended claims.

I claim:

1. Improvements in the process for working gray cast iron containing more than 1.5% carbon, comprising heating the alloy to 950 to 1150 C. and above, and hot rolling the said alloy in this state.

2. The method comprising casting a plate of grey cast iron containingin the region of 3% carbon, heating said: plate to a temperature in the region of 1l50 0., thereafter hotrolling the metal and reheating the metal whenever-the temperature drops below about 900- C. during the rolling to produce rolled shapes of metal containing graphite carbon.

3. The method of making composite productsof steelv and gray cast iron which comprises casting one of said metals in the molten state aga nst the other in "a solid state heating the composite stock to a temperature between about 950' and 1150 C., and hot rolling the stock to the desired shape. N

4. The method of making composite products of steel and cast iron which comprises castind' gray cast iron in moltenstate against steel in a solid state to form an ingot comprising layers. of said metals heatingthe composite stock to a temperature between about 950 and 1150' C.

and hot rolling the stock to the desired shape.

HEINRICH NIPPER.

v t v CERTiFICATE 01 5 CORRECTION. Patent No. 2,241,270. I Ha y 6519141,. V

HE] INRICH NIPPER.

It is hereby certified that erfqr appears in .theprihted-sflclficgtiop of the above numbered 'ptent equiring coire'g tion'gq follovis"; Pag s ec- 0nd column, line 58, claim 2, for the word 'graphit"!read --g:|:-ap'h:Lt1 --j and that the said Letters Patent' ghofild be read-W1 th-thi,s cq'rg eqtiqn 't1 1 er e that the same may conform; to the r ecord of the casein the Patent Offiq. Signedand s ea led this 8th day-0f Jfily, A. 1;; 19L;1;-"

Henry Van Arsdfle, (Seal) Acting Commissioner o f' P at"en ts'.

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