US1049573A - Method of manufacturing steel ingots. - Google Patents

Description

E. GATHMAANN.

METHOD QF MANUFACTURING ASTEEL INGQTS.

APPLIGATION FILED MAB. s, 1909.

` 1,049,573, Y Patented Jan?, 1913.

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various commercial structural ENILGATHMANN, or BETHLEHEM, PENNSYLVANIA,v AssmfNoN. To GATHMANN ENGI- PATENT OFFICE.

NEEBING COMPANY., AOFN1ENT YORK, N. Y., A COBPOBATIONOF MAINE.

` immun or' MANUNACTUNING s'rEEnINeors.

To all 'whom-.fit may con-verm.. i i

- Be itknown that I EMmGA'rHira-NN, a citizen ofthe United States, residing in Bethlehem, in` the county ofv lIIorthamptonand) State of Pennsylvania, have'invented certain newand usefulL Improvements in Methods of Manufacturing Steel Ingots, of which'the following is a specification.

My invention relates rimarily to the casting of steel ingots or a oy ingots which con-l tract in their freezingor solidiiication. from .the-hot -liquid casting'and -which are subsequently pressed, rolled or hammered into shapes and forgings.-

. The primary-object 4offmy invention is to manufacture vsteel ingots in such manner that the so-called e.

or cavity which forms in the upper mi portion of the ingot manufactured'y-by the usual methods. is

, greatly reduced or practically eliminated.

Another-object ofimy invention is to so moldsuc'h ingots that 7ingotismor the formation of large crystals inthe structure ofi.

the ingot is greatly reduced and a further object` of :'mynvention is to provinde a.

cleaner andmore homogeneous steel'casting'.

By my improvements I efect a savingand cro ped or scra ped on account of piping an other imper ections incident to the present manufacturing practices. p In myl application for Patent No. 464,546 filed November 27, 1908, I have descri and claimed certain ynovel molds 'for :practising `the method -herein described and claimed. I herein claim the method of castin in ts by the molds shown in my a lcatiii labove referred tol and the molJd erein'shown.' 'In'. the accompanyin shown a mold adapte to operate inthe manner above stated, but molds of other constructions within the limits hereinafter'speci" fied may be employed. 1

'- Figure 1 hows a vertical Ycentral section 'throuhan ingot mojld whichv may be -emin-carrying out my inventiont Fig.`Y

2 shows a side elevation of themold shownin Fig. l, the stool ,or base-bein'ginselction Fi'g.z.3 shows a' 'horizontal section o n-the `line Specification-of Letters Patent.

- riginal application ledil'ovembera'?, 190B,Seria1 No. 484,548. Divided and this application led lMarch i Serial No. 481,888.A

drawings I "lierre` Patented J an, 7,1913.

I' .'showing a modified way of closing vthe top of' theI mold.

\ v An essential `characteristic ofthe mold is` thatits construction is such that all that 7 part of the moltenmass'below Va relatively` small part thereof at the upper end .of the mold is cooled more rapidly than the remainder of the metal 'in order that the upper portion ofthe molten. mass may feed.

molten metal tov-the pi e,A or cavityP-formed in the lower-portion o the mass while the,

latter is freezing or contracting and until vthe solidification of the ingot isv completed. This may be accomplished inl various ways as set forth in my application foi` patent 'above mentioned. In the mold shown, the lower part below `thellett'ers X-X is relatively thick, while. the upper part of the mold Aabove the letters X-t-X is relativelythin. This insures a quicker absorption of heat from the lower part of the molten mass, 'and the lower-part of the mold below the letters X-X is provided with roughened or serrated surfaces, as indicated at a. As

shown, these surfaces :he provided byl employing horizontally arranged ribs and intervening grooves, as I find this construction tobe well adapted to favor heat radiation. The mold shownhas side WallsA which sol restona stool-B, of -well llmownconstruc'- t-in, and these side walls preferably taper upwardly, as indicated, where they goin the four side-wallsof the upper part C of the 'mold, which are also preferably 'taperedlil The upper part sC is provided withia pourl v ing 'openingw-surrounded by a flange C which is mainly for the-purpose of stren th- 'Y ening the upper art 'of the fmold. he walls` of 'the part, are ma'dethinnerl than the walls A of the lower-part of the-*mold in order that the. lower part of the mold- `may absorbheatmore rapidly .fromv the fluid Q ingotithanf the upper. part of thedmold.l n

Other-.means than t be employed -for giving a aterheat ab# sorption, conduction or radiation qualityl to the -lower of the mo d are arranged to giveA an in-- creased'- 'radiating surface persuperficial -foot areal of the' side 'walls of the lower partof -the mold. The upper-portion of the mold lmay be vformedwith l' lugsD provided with devices D for-conven ose shown,- as set `forth in my above mentioned. application,- may -100 a'rt of the mold. The parts --a ience inhandling or stripping the mold.

. A mold thusl constructed will reduce or practically eliminate piping in the ingot. The freezing or solidifying of the molten mass is progressive from the lower portion of the ingot toward the upper end thereof as is common in all top-cast ingots as the hottest metal lies in progressive layers from the bottom tothe top of the ingot. With my method I obtain a far greater differential of this progressive solidifying of the ingot than has heretofore been obtained.

In order to entirely avoid any possibility of piping and to prevent depressed area at the top of the ingot, I cover the mold with a suitable non-conductor of heat, or a very oor conductor, which should be neutra z. e., it should not have any action on the steel composition.

I may, as shown in Fig. 1, provide a cover E having a handle e or a device by means of which the cover may be lifted and lowered and this cover, as shown, carries a mass c of non-conducting material, such as calcined lime, but other substances which are at once non-conductors, or poor conductors of heat, and `whichphave 4no effect on the material from which the ingot is cast, may be employed. In this Way the heat is conserved at the top or upper portion of the fluid ingot.

Instead of employing a cover, such as Shown in Fig. 1, I may merel fill the top of the mold with suitable pow ered or plastic material, as indicated at G in Fig. 4.

In the usefof my invention the mold is preferably pre-heated to the desired degree in order to avoid sudden strains. The liquid steel is then teemed or poured into the'- moldl from a ladle or the like in any suitable way until the mold is filled, preferably, up to, or near its upper end. The heat from vthe li uid steel is then rapidly conveyed throug the sidewalls A of the lower part of the mold by conduction to the buter surfaces of said side walls upward to the upper I part of the mold and downward through the nstool or platform D. The heat from the ,liquid steel having thus passed by conductionl or absorption to the outer surface 0f the mold is further transmitted by radiation and convection into the surroundin phere. As the speed of heat radiation from any similar body is directly proportional to the exposed surface and as it is also governed by the character of the surface, the heat will radiate far more rapidly from the rou h surface a than from the smoother sur ace C. It thus follows that'the upper portion of the ingot will-retain its heat for a much longer eriod of time than the lower portion thereo or rather, the lower or body portion of the ingot will be cooled far more rapidly 'than 'the portion thereof. Theupperportion o t e moltenf'metal thus atmosbeing the last to cool, will' feed liquid steel to the lower portion of the molten metal as the latter freezes and contracts. This contraction takes place, as is well understood, from a neutral longitudinal axis and usually forms the so-called pipe, but by my improvements this pipe or cavity is automatically illed by the liquid metal fed to it from above and so the pipe or cavity in the casty ingot' is, by my improvement, reduced.

The entiretime of freezing for a given size of ingot is considerably reduced by my improvements as the radiation of heat is greatly enhanced from the major portion of the outer surface of the mold.

The exact location of the line at which the radiation favoring and non-favorin surfaces of the mold meet cannot be de itelyi determined except by experiment for specific sizes and depths of molds, but for the best results I have found that the line of rapid cooling of the ingot should extend to at least 85% of the vertical mass of the ingot when in the molten or liquid state. This does not'necessarily mean 85% of the actual height of the mold but relates to the volume of the same. If the mold were made very wide or of large cross section at the bottom,

the line referred to would be lower than Where the mold is made relatively narrow at the bottom or is of the same width at the bottom as at the top.

Itis Well known that liquid steel when practically deoxidized weighs approximately .256 lbs. per cubic inch while the Alike cold solid steel weighs approximately .284

lbs. per cubic inch. This is a contraction of approximately 10% in volume.

The contraction from said liquid to solid (at white heat) at 1870o F. is approximately 6% and it will thus be understood how the liquid steel floats on the top of the ingot and lioW as the ingot solidifies a gradually decreasing quantity of liquid steel will still remain on the top until the solidication is completed, and how this liquid steel at the tog of the mold can be` fled t0 and made to fil the cavity or pipe tnding to form in the lower part thereof as the steel contracts and increases in specidc gravity.

The coverin of the tp of the mold in' the manner be ore described, not only serves to prevent heat radiation, but it insures the uniform shrinking of the molten mass and thus prevents the formation of a depressed area at the top of the ingot.l

In the use of the mold shown and in practising myr process the metal in the lower represents in to at least 85% `metal during solidiication Ipressed portion e is so far until thesolidificati-on is completed.

I have .hereinbefore stated thatthe Ylinie of rapid cooling of the ingot'should, extend of the vertical mass of the ingot when in the molten or liquid state. By so doing the upper part ofthe mold extent ap roximately twice the extent of the verticai) shrinkage of the and by Vconservingthe heat to the extent just specified, I have found that central plping is practically eliminated from the ingot and the dereduced as to be lnconsiderable as compared with the present practice.

clalm asm invention: 1 The herein escribed' method'of casting steel ingots, whereby piping is reduced which consists in retarding the radiation of the heat of the ingotv from the upper portion thereof and 'in progressively accelerating the radiation of heat from the lower portion of the ingot toward the top to an extent approximately 85% ofthe mass of the molten metal to cause the upper portion 'of the mass t feed molten metal cavity tending to form in the upper central portion thereof while the metal is freezlng or contractin and to thus cause the pi e to rise toward t e top of the ingot and dlsappear in the upper ortion of the ingot where the radiation of t e heat is retarded;

' In testimony subscribed my name.

EMIL GATHMANN.

YVitnesses: l

IsABEL GATHMANN,

WILMUTH) GARL to the pipe or whereof, I have hereunto

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