US2125172A - Process of treating the defective surface metal of billets or the like - Google Patents

Description

July 26, 1938.

PROCESS ,0! TR A. B. KINZEL 2,125,172-

EATING THE DEFECTIVE SURFACE METAL 0F BILLETS OR THE LIKE Original Filed July 29, 1932 2 Sheets-Sheet 1 ATTORNEYS July 26, 1938. A.' s. KlNZEL 2,

PROCESS OF TREATING THE DEFECTIVE SURFACE METAL OF BILLETS OR THE LIKE ,origiha l Filed July 29, 1932 2 Sheets-Sheet 2 FIGHI INVENTOR AUGUSTUS B.KINZEL ATTORNEY Patented July 26, 193

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PROCESS OF TREATING THE DEFECTWE SURFACE METAL F BILLETS OR THE LIKE York

Application July 29, 1932, Serial No. 625,637 Renewed October 10, 1936 15 Claims.

My invention relates to a process of treating metallic bodies to eliminate defects, such as cracks or defectively bonded metal and abrupt irregularities of contour, from their surfaces.

I My invention is particularly useful in the manufacture of steel. In this art the steel, first in the form of ingots, then blooms and then billets, is successively rolled at a high temperature. The working of the metal in any of these rolling steps often causes the surface of the metal to crack and form crevices known as snakes. The walls of these cracks become coated with oxides which prevent them from being welded together during the further rolling of the metal. Frequently, the defects or faults, such as cracks and poorly bonded metal, are rolled into the body of the metal and become concealed during the rolling operations. Also, when metal containing such defects is rolled, the defects increase inlength in proportion to the reduction in area of cross-section of the metal object being rolled. Therefore, whenever such cracks occur in the metal it is necessary that they be. eliminated before the metal is further rolled. It is also necessary that, upon eliminating the cracks or poorly bonded metal, the surface of the metal be left free from abrupt irregularities of contour. That is, the abruptness of the slope of the sides of the elevations or depressions must not be so great that the oxide coated sides will be folded over 'on each other when rolled out and produce folds of oxides within the metal when further rolled.

Heretofore, the defective surfaces of blooms or billets have been prepared for subsequent rolling operations by cutting out the surface, portions which contribute to the production of defects in the rolled or finished product. The removal of the surface portions has been effected by mechanical methods, such as chipping or milling, and more recently by the use of a highly oxidizing stream of gas. Before the metal is operated upon by any of the prior methods mentioned herein, the hot metal is allowed to cool to a comparatively low temperature to allow the inspectors. to get close enough to the metal to detect and mark the undesirable metal portions to be removed, and to allow the metalv removing operators to get close enough to operate upon the metal. During this cooling period time and heat energy are lost as well as the time consumed during the reheating of the metal for subsequent rolling.

The process of milling and chipping is very laborious and it consumes a great amount.of time. While the process of removing the unde-' 55 sirable metal portions by the use of the oxidizing gas stream is less laborious and quicker than milling or chipping, .it, like the prior methods, cuts away substantial portions of the metalwhich is a waste. The loss of metal is due in part to the fact that it is necessary to cut out wide gouges to provide depressions having sides with slopes within the necessary minimum degree required to prevent the sides of the depression from being folded over when rolled.

Therefore, one of the objects of my invention is to provide a process of eliminating surface defects from metallic bodies to prepare the surface of the metal for subsequent metal working processes which shall conserve time, labor, heat and metal.

Another object of my invention is to provide a process for converting the surface of a metallic body into a relatively smooth homogeneous mass firmly bonded to the body metal and substantially free from oxide inclusions.

Another object of my invention is to provid a process which eliminates the necessity for inspecting the surface of the metal for defects.

In accordance with my invention the foregoing objectsmay be accomplished by applying localized high temperature heat for melting defective portions of the surface to the depth of the defective metal and thereby eliminating the oxide from the surfaces of the cracks and the poorly bonded metal so that, upon solidifying, the surface will be welded together in a smooth homogeneous mass to the body metal. Preferably, the surface is melted with one or more electric arcs which may be applied to the defective portion only, or to the entire surface of the metal. The arcs may be applied to the surface while the body of the metal is cold or immediately after it has been but worked. In some instances it may be desirable to subject the surface of the metal to the heat of the electric are immediately after it has passed through the hot rolling operation for the purpose of conserving the heat in the metal at that point and to save the time and heat required to heat the metal up for subsequent hot working operations. In such a case the metal is not inspected for defects and the entire surface of the metal is treated with a plurality of arcs.

One process of fusing the surface metal is illustrated in the accompanying drawings in which:

Fig. I is an isometric view of an apparatus operating upon the surface of a bloom or billet; Fig. His a fragmentary sectional view of a modified detail of the apparatus shown in Fig. I; and

Fig. 111 is a diagrammatic view illustrating the the blocks.

location of the apparatus shown in Fig. I when arranged between two roll stands for treating the surfaces of billets during their movement between rolling operation.

As shown in Fig. I, the billet I to be treated is supported on rolls 2 as it is passed through a main stationary frame 3 which supports a plurality of carbon electrodes 4. An arc is drawn between one end of each of the electrodes and the metal surface to be treated. Each of the arcs is struck and regulated automatically by any of the suitable well known automatic arcstriking and electrode feeding devices. For clearness the electric circuit and a device 5 for regulating only one of the arcs is shown diagrammatically.

In the circuit shown, a generator 6 provides a source of current for the arcs. Preferably the positive side of the generator 6 is connected to the billet I and the negative side is connected to each of the electrodes 4. Each of the electrodes is held by an electrode holder 1. The holder 1 is actuated to strike and regulate the arc in the usual manner by a plunger 8. The plunger 8 is actuated by a solenoid 9 in series with the arc circuit. However, other suitable means for striking and regulating the arc may be employed.

The electrodes 4 are arranged in batteries in refractory insulative blocks III which are secured in slidable frames II, I2, I3, and I4. Each of the electrodes 4 is slidably guided in bores I5 in The electrodes are arranged in rows and are staggered in relation to each other so that the arcs will play upon different portions of the billet I as it passes through'the main frame 3. The number of arcs may be varied as the conditions may require.

There may be as many batteries of electrodes as are required to play the arcs on all of the sides of the metal whose surface is treated. As shown, the billet I has four sides and a battery of electrodes is provided for each side. As the billet passes through the frame 3 in the direction of the arrow A the electrode blocks I 0 may be held stationary so that the travel of the arcs along the surface of the work will be a straight line. In such a case the apparatus hereinafter described may be eliminated.

In order to cover the surface of each side of the billet more effectively the batteries of electrodes are given a movement transverse to the movement of the billet I as it passes through the main frame 3. For this purpose each of the slidable frames II, I2, I3, and I4, in which the electrode blocks II) are mounted, is provided with grooves IS in opposite edges thereof which slidingly engage ways or lands I! on the main frame 3. The electrodes mounted in the top slidable frame I I and in the near side slidable frame I2 are given the transverse movement by the rotation of a cam I8 keyed to a shaft I9 journaled in the upper near corner 20 of the main stationary frame 3. When the cam I8 is rotated, the high,

point 2I of the cam moves the slidable frames I I and I2 along the lands II in the stationary frame 3 away from the cam shaft I9 and transversely of the movement of the billet I. The slidable frames and I2 are given a return transverse movement by springs 22 and 23 compressed between the stationary frame 3 and each of the end edges of the slidable frames most distant 'from the cam I8. The springs 22 and 23 are maintainedin place by pins 24 which pass through the coils of. the springs. One end of each pin 24 is secured to the main frame 3 and the otherend slides in a bore 25 in its respective slidable frame II or I2.

The bottom battery and the far side battery of electrodes are mounted in a manner similar to the other two batteries of electrodes in relation to a cam 26 and springs 21 (one of which is not shown) acting in opposition to the cam 26 on the edges of the slidable frames most distant from the cam for giving the electrodes 4 a transverse movement.

A bevel gear 28 is keyed to each of the cam shafts I9 and 29. The gears 28 on the cam shafts are geared together by a horizontal shaft 30 and a vertical shaft 3|, each having a gear 32 on one end meshing with one of the cam shaft gears 28 and gears-33 on the other ends meshing with each other. A bevel gear 34 keyed to a shaft 35 journaled in a bracket 36 on the main frame 3 meshes with a bevel gear 31 on the cam shaft 29. The cams I8 and 26 may be rotated through the train of gears described by a crank 38 on the shaft 35 journaled in the bracket 36 or by power operated means or the like connected to the shaft 35.

In some cases it is preferred to protect the electric arcs from the surrounding air to prevent the surface of the metal from being oxidized by the action of theatmospheric oxygen in contact with the exposed arcs. For this purpose, as shownin Fig. II, the electrodes 4 are slidably mounted in bushings 39 which in turn are mounted in the blocks III. A protective gaswhich is inert in respect to the metal, such as hydrogen, is supplied through an inlet 40 to a cavity M in the bushings. The gas is discharged through an outlet 42 which is larger than the electrode 4 to allow the gas to envelop the electrode and the are drawn between the surface of the metal I and the electrode 4.

When, as hereinbefore described, billets are subjected to the surface conditioning treatment immediately after they have been hot-rolled and while the are still hot, the surface conditioning apparatus according to the invention, may be interposed between sections of the roller conveyor that carries the billet from'one roll stand to the next as illustrated in Fig. III. The billets I, after being hot-rolled by the roll stand 43 in the customary manner, are conveyed and guided by the rollers 2 through the surface conditioning apparatus indicated at 44 which has been previously described in detail and which is here shown enclosed within a protective covering supported by the frame 3. The billets I, after the surface treatment, may pass from the apparatus 44 along the set of rollers 2 on the discharge side of the conditioning apparatus 44 to another stand of rolls 45 which subject the treated'billets to another hot rolling operation. While I have shown a plurality of machine operated electrodes for treating the surface of a billet, it is to be understood that my process may be carried out by one or more manually operated electrodes, and that the arcs may be applied to the defective portions of a surface only. It is also to be understood that other forms of apparatus may be used to carry out my process without departing from the scope of my invention as defined in the appended-claims.

I claim:

1. The process of treating metallic bodies to transform their defective metallic surfaces into a suitable condition to be rolled, comprising directing at least one electricarc upon the defective portions said are or arcs being formed beanaem a tween a negative carbon electrode and the positive metallic body; melting said portions with said arc whereby substantially to eliminate the defects from the surface; and bonding the melted portions to the remainder of the body metal.

2. The process of treating metallic bodies to transform defective surface portions into a suitable condition to be rolled, comprising subjecting the surface of the metal to the heat of a plurality of electric arcs, said arcs being formed between negative carbon electrodes and the positive metallic body; melting the surface with said arcs and producing a surface metal of substantially the same composition as the sound body metal whereby substantially to eliminate the defects from the surface, and bonding the melted portions of the metal to the remainder of the body metal.

3. The process of treating a metal body such as an ingot, bloom, billet,'or the like to trans form defective surface portions thereof into a tially to eliminate the defects and that the composition of the n" so melted is substantially unchanged.

, 4. The process of treating a metal body such as an ingot, bloom, billet, or the like to transform defective surface portions thereof into a suitable condition to be rolled, which process comprises subjecting simultaneously defective portions located on at least two surfaces of the body in different planes to the heat of a plurality of electric arcs and effecting relative parallel motion between said arcs and said surface portions, the amount of current supplied through said arcs and the rate of speed of said motion being so regulated that the said surface portions are melted to'a depth suflicient substantially to eliminate the defects and that the composition of the metal so melted is substantially unchanged; and bonding at least a major part of the melted metal to the remainder of the metal body.

5. The process of treating a metal body such as an ingot, bloom, billet, or the like, which comprises hot rolling said body to reduce its cross section, thereafter but beforethe body has cooled below rolling temperatures subjecting substantially the entire surface of said body to high temperature heat whereby to melt said surface to substantially the depth of surface defects therein contained, and then further hot rolling said body to reduce its cross section.

6. The process of treating a metal body such as an ingot, bloom, billet, or the like, which .comprises hot rolling said body to reduce its cross temperature heat whereby to melt said surface to substantially the depth of surface defects therein contained, .bonding at least a major part of the metal so melted to the remainder of the body,

and then further hot rolling said body to reduce its cross section.

'7. Theprocess of treating a metal body such as aningot, bloom, billet, or the like, which comprises hot rolling said body to reduce its cross section, thereafter but before the body has cooled below rolling temperatures subjecting substantially the entire surface of said body to the heat of a plurality of electric arcs whereby to melt said surface to substantially the depth of surface defects therein contained, bonding at least a major part of the metal so melted to the remainder of the body, and then further hot rolling said body to reduce its cross section.

8. The process of treating a metal body such as an ingot, billet, or the like, which comprises. hot rolling such a body to reduce its cross section; thereafter but before the body has cooled below a rolling temperature subjecting at least a portion of the surface of said body to high temperature heat whereby to melt such surface portion to substantially the depth of surface defects thereon; and then further rolling said body to reduce its cross section.

9. The process of treating a metal body such as an ingot, bloom, billet or the like, which comprises hot rolling said body to reduce its cross section; subjecting simultaneously a plurality of sides of said body at an intermediate point in the course to the rolls to a high temperature surface treatment whereby surface metal may be elevated substantially to the melting temperature; and thereafter further rolling said body when at said elevated temperature.

10. A process of treating a metal body such as a steel ingot, bloom, billet or the like, which comprises hot rolling said body to reduce its cross section; moving said body in the direction of its length and subsequently hot rolling said body to again reduce its cross section; and, before said body has cooled below a rolling temperature and while it is moving from one hot rolling operation to the subsequent hot rolling operation, progres-' sively subjecting at least a portion of the surface of said body to localized high temperature heat whereby fusion of the surface metal results and defects of such surface portion are substan- 1 tially eliminated to provide asurface which is in a suitable condition for the subsequent hot rolling operation.

11. The process of treating a metal body such as an ingot, bloom, billet or the like, which comprises uniformly heating said body to a desired rolling temperature; moving said body in the direction of its length and hot rolling said body to reduce its cross section by a plurality of successive steps whereby its surface area is increased and its temperature reduced; and, at a point between said steps while said body is moving from one hot rolling operation to the subsequent hot rolling'operation, subjecting a relatively narrow portion of surface extending completely across said body to localized high temperature heat so as to progressively raise the temperature of the whole surface'to a fusion point and thereby provide a surface that is in a desired condition for the subsequent hot rolling operation.

12. The process of treating a metal body such as an ingot, bloom, billet or the like, which comprises uniformly heating said body to a desired rolling temperature; moving said body in the direction of its length and hot rolling said body to reduce its cross section by a plurality of successive steps whereby its surface area is increased and its temperature reduced; and, at a point between said steps while said body is moving from one hot rolling operation to the subsequent hot rolling operation, simultaneously subjecting a relatively narrow portion of surface metal extending completely across opposite sides of said body to localized high temperature heat so as to progressively raise the temperature of said sides to a fusion point and thereby provide surfaces that are in a desired condition for the subsequent hot rolling operation.

13. The process of treating a metal body such as an ingot, bloom, billet or the like, which comprises uniformly heating said body to a desired rolling temperature; moving said body in the direction of its length and hot rolling said body to reduce its cross section by a plurality of successive steps whereby its surface area is increased and its temperature reduced; and, at a. point between said steps while said body is moving from one hotrolling operation to the subsequent hot rolling operation, simultaneously subjecting a plurality of sides of said body to the heat of a plurality of electric arcs so as to progressively raise the temperature of said sides to a fusion point and thereby provide surfaces that are in a desired condition for the subsequent hot rolling operation. i

14. In a process of treating a metal body such as an ingot, bloom, billet, or the like, in conjunction with hot rolling said body to reduce its cross section; the steps which comprise subjecting at least a portion of the surface of said body to a fusion temperature produced by applying electric arcs through electrodes; supplying a protective gas so directed as to surround said arcs and impinge on the surface being treated; preheating the gas supplied by causing the gas to flow longitudinally of and in contact with said electrodes w iereby said electrodes are cooled; and effecting relative motion between said arcs and said body.

15. The process of treating-a metal body such as an ingot, bloom, billet, or the like, which comprises hot rolling said body to reduce its .cross section in a plurality of steps; briefly subjecting portions of the surface of the body to a fusion temperature produced by applying electric arcs to such surface while said body is substantially at rolling temperature and moving from one rolling operation to the subsequent rolling operation; and moving said body longitudinally with respect to said arcs while reciprocating said arcs transversely of said body so as to treat the whole surface and render it in the desired conditio for subsequent hot rolling.

AUGUSTUS B. KINZEL.

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