US1680493A

US1680493A - Method of removing piping and unsound metal from ingots

Info

Publication number: US1680493A
Application number: US556241A
Authority: US
Inventors: Samuel S Ball
Original assignee: Individual
Current assignee: Individual
Priority date: 1922-04-24
Filing date: 1922-04-24
Publication date: 1928-08-14
Anticipated expiration: 1945-08-14

Description

I Aug. 14, 1928. f 1,680,493

S. 5. BALL IETHOD OF REMOVING PIPING AND UNSOUND METAL FROI INGOTS Filed April 24. 1922 gnu-mm Patented Aug. 14, 1928.

sum 8. BALL, OF'BETHLEHEM, PENNSYLVANIA.

METHOD MOVING PIPING AND UNSOUND METAL FROM INGOTS.

Application and April 24, r9122. Serial No. 556,241.

The present invention relates to methods of removingunsound metal from ingots and particularlyto methods of removing piping and segregations of impurities 'from ingot to s.

it has been found, in the manufacture of steel, a practical impossibility to prevent the formation of piping, blow-holes, and segre- Igations of impurities in ingots. The ipmg occurs centra ly of the ingot and at its top for the most part, and is caused byuneven cooling of the metal, as is well known. Segregations of impurities are caused by the forcing of such impurities toward the center of the ingot as the ingot gradually solidifies in cooling from its outer surface toward its center. Generally, the piping and segregation of impurities occur to any considerable extent only at the top of the ingot, the imurities gathering ad acent'the bottomof the 1 e. To free the ingot of these impurities 1t as heretofore been generally found -neces sary to cut off the entiretop portion, the

volume of which is relatively large as compared with the total volume of the ingot,

and to discard this portion.

' It has been suggested that the impurities iping ressure t ereon,

may be removed from ingots and prevented, by exerting a 0 while the metal is in a fluid state to force the gases forming in the center of its top and the. metal containing impurities gathered at this point, u wardly through a central opening in'a escendln piston head 5 or die which closely fits wit in the upper end of the mold in which the liquid metal is contained. In theory the liquid metal which would develop unsoundness if left with the remainder of the metal to solidify D is removed by this process, but in practice 1 it isfound that a portion only of the impurities is removed, due tothe fact that the segregation is not complete when the pressure is applied to-the fluid metal, and that piping 5 and segregation still occur within the main body of the ingot and frequently of suflicient seriousness to renderthe ingot unsuitable for certain pur ses. The present method contemplates the a .treatment of the ingot while in a. plastic state, by means which exerts a pressure on the sound metal surrounding a portion of unsound metal, to force the sound metal toward the body of the ingot to displace the 5 unsound metal. This unsound metal forced outwardly and forms a projection which may be easily removed. The method may be employed to remove unsound metal from any part of an ingot roviding it is adjacent the 'outer surface wiere it may he observed, but is principally employed in the removal of the unsound metal and piping from the top of the ingot.

Pressure is applied only after the piping has been completely formed and the segregation of impurities completed. An ingot in a plastic state, which may have been heated as a preparatory step, or which may be cooling after having been cast, is dis posed vertically in a confining die which is slightly larger III-hOIlZOIItfll cross section than. the ingot. Pressure isv then exerted by an upsetting die upon the upper surface of the ingot to flatten out this upper surface and to shorten and thicken the ingot so that it bears against the wall of the confining die at all oints. A displacement die is then applied to the top of the ingot, which has a central recess in its bottom of considerable size leaving a narrow marginal surface around this recess which is adapted to bear on the sound metal at the sides of the ingot. Downward movement of the displacement die causes the sound metal ofthe margins of the ingot to be forced into the body of the ingot to displace the unsound metal, this metal flowing upwardly and entering the recess in the displacement die. When the operation has been completed the unsound metal is nearly all contained in the knob or lug pro'ecting from the upper end of the ingot an when this is removed'the ingot is practically free of localized segregations of impurities.

In addition to eflecting the isolation of the impurities in this manner so that they may be removed with a minimum of loss of metal,.there area number of other advantages flowing from the application of the method. The action of t e upsetting and displacement dies on the metal results inthe v refining of its structure and particularly the refinement of the surface metal. Blow-holes throughout the ingot are closed up. The

base knobs or projections which protrude from the bottom'of the ingot due to erosion of the mold stool, are eliminated. In addition, only a shorttime is required to carry out themethod, several'minutes only being necessary, whereas-"when an ingot'in thefluid stageis-treated an hour or more 'is v necessary. Furthermore, the displacement of the metal in accordance with the Hresent outer wall of the ingot, as shown in Figure method may be carried out to any esired 3, the space 'Wlthlll the walls of the conextent, it being within the power of the operator to stop the movement of the die at any oint.

W ere the ingot is to be subjected to a subsequent rolling operation, as in the case of the fabrication of rails, I beams, or other structural shapes, the method is particularly beneficial. The compression 0 the ingot longitudinally and expansion laterally while in the confining mold is exactly the reverse of the process of rolling, in which the ingot is reduced in section and increased in length. The working of the metal as a preliminary step in a manner exactly the reverse of that in which it is worked in a subsequent rolling operation, improves the physical qualities of the steel and refines the grain so that the resulting rolled articles are of superior quality.

In the accompanying drawin s:

Figure 1 is a central longitudinal section through a typical ingot as it comes from a casting mold;

, Figure 2 shows the ingot in section, the bottom of the ingot resting in a cup die which forms part of the confining die;

Figure 3 shows the ingot completely enclosed by the confining die and with the upsetting die in operative position;

Figure 4 shows the condition of the ingot at the com letion of the movement of the up-setting ie;

Figure 5 shows the displacement die in operative position;

Figure 6 shows the displacement die at the completion of its movement;

Figure 7 illustrates the ingot in vertical section at the completion of the last step and after removal from the confining die; and

Figure 8 is a section on the line 88 of Figure 6.

The ingot illustrated in Figure 1 is typical.

' per surface, and irregular knobs 12 projectng from its lower end due to the wearing away or erosion of the moldin which it was cast. Around the base of the pipe 11 is a portion 13 of metal which is unsound due to the inclusion of impurities or segregations. It issought to remove the pipe 11 and the unsound metal 13, and the first step of the process is to place the ingot, which is in a heated and plastic state, on a plate 14 with thelower end of the ingot resting in a cup-shaped depression 15 formed in the plate. The two halves 16 of a separable die are then brought together to enclose. the ingot, the ortions 16 orming, with the plate 14, a con ning die completely surrounding the ingot except at the top. The inner walls.

of the die are spaced somewhat from the stood that it is fining die being greater in cross section than the ingot. The up-setting die His next applied to exert a downward axial pressure on the ingot which shortens and thickens it and causes it 11) expand laterally to fit against the walls of the die, as s own in Figure 4.

The up-setting die is now removed and replaced by the displacement die 18. This displaceinent'die has a central stepped recess 19 in its lower end, the margins only of the lower face of the die being adapted moved downwardly sufficiently, the recess 19 may be completely filled with metal, as shown in Figure 6.

When the operation has been completed the ingot is removed from the confining die and it will then be seen that the piping has been eliminated and that the unsound metal has been isolated and is all within the lug or projection extending axially from the.

ingot top.- This projection may be severed without difficulty, leaving the remainder of the in ot free from unsoundness. The bottom 0? the ingot has also been rounded and the lugs 12 removed. Not only is the piping removed and impurities of the ingot isolated in a minimum of time, but the grain structure of the metal is refined during the operation and its physical roperties improved. The method is especia 1y useful where the ingot is to be sub uently rolled, the steps of the above descri (1 method when combined with the steps of a rolling operation, resulting in a structural shape of high quality. While the method is described as applied to an ingot of well known type having a square cross section, it will be underegually applicable to round in ots or in ots 0 any shape.

aving t us described my invention what I claim as new and desire to secure by Letters Patent is:

1. The method of freeing the body of an ingot of iping and segregations in the top thereof w ch includes the step of applying forces tothe ingot entirely in a "direction truly axial of the latter and when the latter is in a plasticstate to effect the flattening of the upper end of the ingot, and the step of applying forces entirely in an axial d1- rection to the margins of the ingot top to force the sound mar inal metal into the bod of the ingot an to displace the central y'located unsoundmetal.

2. The method of treating ingots having unsound terminal 'core portions surrounde by sound metal which consists in applying forces to the end of the "ingot having the unsound terminal core portion and axially of the ingot to secure contraction of the unsound core portion and thickening of the sound metal surrounding the latter and then in applying forces axially of the compressed ingot and in annular zones to the sound metal surrounding the contracted core portion to secure further compression of the ingot and the extrusion of the unsound metal of the core portion.

3. The method of forming rolled articles consisting in uring an ingot, cooling the ingot below t e temperature at which blow holes and segregates are completely formed,

heating the ingot to a temperature at which it becomes plastic, applying ressure to the sound metal surrounding thev metal containing the blow holes and. segregates to extrude the latter beyond the main portion of the ingot, and then rolling the ingotfi 4. The method of forming rolled articles consisting in pouring an ingot, cooling the ingot below the temperature atwhich the blow holes and segregates are completely formed, heating theingot to a temperature at which it becomes plastic, com ressing the ingot through its entire lengt applying pressure to the sound metal surrounding the metal containing the blow holes and segregates to extrude the latter beyond the main portion of the ingot, and then rolling the ot. In testimony whereof I hereunto afiix my signature.

SAMUEL s BALL;