US1108862A - Method of treating ingots. - Google Patents

Description

G. CRAWFORD. METHOD OF TREATING INGOTS. APPLICATION TILED MAILBI. 1913.

1 9 1 Q8, 86 2 I Patented Aug. 25, 1914;

B SHEETS-SHEET 1;

G. G. CRAWFORD. METHOD OF TEEATING INGOTS.

APPLIGATIOH FILED 14413.31. 1913.

Patented Aug. 25, 1914.

3 BKEIJTS SHBET 2 G. G. CRAWFORD. METHOD OF TREATING INGOTS. APPLIOATIQE FILED MAILSI, 191s.

Patented Aug. 25, 1914.

3 SHEETSSHEET 3.

- operation.

GEORGE G. CRAWFGBD, O3? BIRMINGHAM, ALABAMA.

METHOD 0F TREATING INGOTS.

Specification of Letters lPatent.

lratentcd ring. this.

Application filed March 31, 1913. Serial No. 757,968.

To-aZZ whom, it may concern Be it known that I, Gnonon Gr. CRAWFORD, a citizen of the United States, and resident of Birmingham, in the county of Jefferson and State of Alabama, have invented certain new andus ejul Improvements inMethods of Treating Ingots, of which the following is a specification. My invention relates to the art of metal rolling and has partirrlarreferenceto a novel methodof ingot treatment whereby the finished rolled product shall be free from some defects c'ausedby the rolling process.

Much attention has been directed to the failure of railroad rails, these failures very frequentlyoccurring in rails rolled from the top part of an ingot. However, of late there have been many failures in rails produced from tlia bottom portion of the ingot where the steel is supposed to be sound. The majority of these failures are due to the fact that the rolls in the booming mills or other rolls which make the first pass on all ingots are oi? relatively small diameter con'ipared with the thickness of the ingot, and the molecules of the ingot when they have as yet had no'fiow motion imparted to them are less cohesive. The efiect of the bite of the roll on the ingot in this tender condition is to drag the piece of steel through the rolls in much the same manner as a piece of steel. is pulled through a die, and the draft and speed at which this work is done is so great that the sides of the ingots are torn, and defects are produced which are not corrected in the later rolling ln order to overcome the dithcultics mentioned and to so manipulate the ingot that the surfaces thereof may he made more dense and less liable to be torn in the first pass ot-th'e mill, 1 provide at a point between the soaking pit and the blooming fnill a powerful forging press or presses, whereby, by a forging action. the surface of he'mgot is made tough and dense. In the forging action the complete reduction is made in two overlapping strokes; that is,

one portion of the die will complete the reduction begun by another portion in, the preceding stroke. Preferably the ingot w ll be worked on two sides simultancmisly, then given a quarterturn and passed tl'irough the same or another set of dies whereby the unworked surfaces are treated. The latter; form is theoretically preferable forthe rea-' son that the cracks or fissures usually appear at the corners of the ingot. I 111 practice the illustrated form will be found desirable. This 'forging action will not materially elongate the ingot, but its sides will be made parallel, that is, the cross sectional area will be substantially uniform throughout. v

The invention may be stated broadly as consisting in the method'of treating ingots in which an ingot is first suitably heated, then subjected to'a forging process whereby a flow of the molecules is iniparted and the surface made more tough and, dense, previous to rolling the ingot in the usual manner.

Mechanism by which my improved method may he carried out is shown in the accompanying drawings, wherein,

Figure 1 is a side elevation of a forging press for use in forging ingots as described: Fig. 2 is a transverse vertical section V g L 0 through the iorging dles as shown in Fig. 1;, Fig. 3 is a s ction on the line 3--3 of Fig. 2: Fig. isa section on the line 47-1 of Fig "3; Fig. 5 is a diagrammatic plan of a plant adapted for carrying out my improved method, and, Fig. (3 is a view of an ingot showing in dotted lines the degrees of reduc- 'tion throughout its length.

Referring more particularly to the drawsource of power. The shaft 15 is over-hung at one end and provided \vitha counterweight 19, which may act to augment the force of the forging stroke. At a point between the bearings in the housings 11, 12, the shaft 15 is eccentric as at 20, in Fig. 2.

This eccentric portion is located between two integral annular rings or collars 21, which bear against portions of the housings 11, 12. Carried by this eccentric'portion is a pitman 22, pivotally connected to a cross-head 23. by means of pins 2 1, which are adapted for limited sidewise movement as required, the recess within which the pins are retained permitting such movement. The cross-head However, 7

The shaft 18 is connected to a suitable is adapted for vertical movement between Ways 25, onthe sides of the housings 11, 12.

This provides for the :necessary strength and at the same time permits theoscillation of the pitman. The lower face of the crosswith parallel sides and, all the head 23 is provided witha dovetailed recess Within which is fitt'ed the forging die 27, the faceofjwhich maybe given-the de} sired contour, thatshown in Fi '2,"being preferable. By such contour of the 'die the reduction of the ingot will be substantially "shown on the upperface of'the-ingot in Fig. 6; that is, the complete reduction is not secured in any one stroke, the strokes overlapplng.

The bottom die 28 i s' fitted within the base 10, and its working face maybe sha ed as desired. That shown in Fig. '2 is be ieved to be preferable. The reducing strokes will overlap but the reduction will not be'as great as that on the upper surface of the ingot.- ,However, the ingot Will be finished have been worked.

As shown in Fig. 6, the origihal'iehgth the ingot may. be as shown by thefdifmension line A, the final length being represented by the dimension line B. The original diameter of the ingot at the top is represented by C,

- at the bottom by D, and the finished diameter by E, which diameter is uniform throughout the length of the ingot. It will thus be seen that the elongation is not material,

neither is there material reduction in the cross-sectional area at the top of the ingot.

The method will preferably be carried out with an arrangement such as shown in 5. It is assumed that the-ingots have been .suitably cast and; stripped and thereafter placed in "soaking pits 29. From the soaking pits they are removed and placed on. the ingot chariot and thereafter delivered in front of a hydraulic pusher 30, by means of which they are transferred to a roller table 31. From ti-c roller table they are passed through the first forging press 32, wherein two sides of the ingot are reduced as shown in dotted lines in Fig. 6. From the press 32, the ingots are delivered to a second press 33, where-the other two sides are treated. From the press 33 the ingot is delivered in front of a second hydraulicpusher 34, and returned to an ingot'chariot or delivered directly onto the blooming mill roller table. The ingots are then passed through the sui'faces will blooming mill 35, the steps from there on being as usual in rolling operations.

.Byfollowing the method herein described it will be found that ingots are produced which possess a dense and tough surface .not easily torn by the passage of the ingot 'throughthe first pass of the blooming mill with the usual consequent great reduction in area. I

The heating of the ingot referred to in the claims may consist inutilizing the heat contained "in; the ingot after it has been poured and becomes solidified or the ingot" l. The method of treating ingots which consists'in first suitably heating the same,

then forging the ingots between dies in. order to toughen and improve their struc til'refthen rolling the ingots, substantially asdescribed.

2. The method of treating ingots which consists in first suitably heating the same,

then forging two opposing surfaces of the ingots in order to change the molecular structure thereof, then rolling the ingots,

substantially as described.

3. The method of treating ingots, which consists in suitably heating the same, then forging two opposing surfaces,'then forging two additional opposing surfaces whereby the cross section of the ingots is made substantially uniform and their outer surfaces aredensified and toughened, then rolling the ingots, substantially as described.

4.. The method of treating ingots, where by the tearing of the surfaces thereof in the first rolling pass is avoided, which consists in first suitably heating the ingots, then forging their surfaces and making theingots of substantially uniform cross section, then rolling the ingots, substantially as described.

5. The method of forging ingots which consists in placing an ingot between opposing dies, partially reducing 'a transverse dimension of said ingot in one stroke of the die and in another and later stroke of the die completing the reduction and partially reducing an advanced portion of the ingot, substantially as described.

GEORGE G. CRAWFORD.

Witnesses CHAS. F. MURRAY,

' H. C. Rrnmo.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. t3.v

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