US2210921A - Process of and apparatus for conditioning metal bodies - Google Patents

Description

4 Sheets-Sheet l H. W. JONES ET AL Filed May 29, 1957.

lw l I 1 PROCESS OF AND APPARATUS FOR CONDITIONING METAL BODIE Aug. 13, 1940.

g- 13, 1940- N H. w. JONES ET AL 2,210,921

PROCESS OF AND APPARATUS FOR CONDITIONING METAL BODIES INVENTOR5 HOMER wdo/vfa JAMES HBl/CKNAM BY 0mwa 4170;25

ATTORN EY Aug. 13, 1940- H. w. JONES ET AL PROCESS OF AND APPARATUS FOR CONDITIONING METAL BODIES Filed May 29, 1937 4 SheetsSheet 3 8M J 0 NW? U I. WRHQIW \mm mm mm v0 M 6 .QmH|m .8 WWW 7 mm .8 mm 1 mm 0 m wm S T vm. F 4% m 8 mm No 3 E 3 HH- 3 8. mm 8 xi m mm 13, '1940- H. w. JONES ET AL 2,210,921

PROCESS OF AND APPARATUS FOR CONDITIONING METAL BODIES Filed May 29, 1937 4 Sheets-Sheet 4 I N V EN T0 R5 HOMER MJO/VES JAMES IV- BUCK/VAN y :mrwvo 40071:

' ATTORNEY Patented Aug. 13, 1940 UNITED STATES PATENT OFFICE PROCESS OF AND APPARATUS FOR CONDI- TIONING METAL BODIES Application May 29, 1937, Serial No. 145,480

41 Claims.

This invention relates to the art of conditioning the surfaces of metal bodies, and more particularly to a process of and apparatus for thermo-chemically desurfacing semi-finished steel shapes, such as billets, blooms, bars, and slabs, which are utilized in the manufacture of steel products.

During the rolling of steel, defects and seams appear in the surfaces of the semi-finished shapes and, in order to reduce the number of rejections of finished products subsequently produced, it is desirable to condition such shapes to remove such defects. Apparatus has heretofore been employed for simultaneously conditioning two opposing side faces of semi-finished steel shapes during the processing of such shapes in a steel mill. In order to desurface all the lateral surfaces of a body in such prior apparatus,

either two such desurfacing devices must be arranged in series, together with means between such devices for manipulating the body so as to present the untreated faces to the nozzles of the second desurfacing machine; or, when only one desurfacing machine is used, the body must be re-positioned after the first pass through the machine to present two more surfaces for treatment, then the body must be returned to the entering side of the machine and finally passed through the machine a second time.

In accordance with the present invention, a procedure and apparatus are provided whereby the desurfacing of all lateral feces of semi-finished shapes can readily be effected simultaneously in a. single passage during the normal and progressive production of the semi-finished steel, so that a substantial reduction in the cost of manufacturing steel products is effected by eliminating the loss of manipulating time. Addi-.

which can readily be incorporated in a conventional rolling mill of a steel plant, whereby the desurfacing of semi-finished steel shapes becomes an integral step in the processing and conditioning of steel; to provide mechanism for stopping trol vide apparatus for carrying out such process 1 and positioning successive semi-finished steel shapes on the conveyor rollers before each desurfacing operation is initiated; to provide means for simultaneously delivering oxidizing gas streams obliquely against the longitudinal sur- 5 faces of the successive semi-finished shapes whereby all of the sides thereof are entirely desurfaced in a single pass; to provide apparatus for thermally conditioning longitudinal surfaces of a row of steel bodies or shapes including mechanism for moving the gas delivering means into or out of operative alignment with the row of bodies or shapes; to mount the gas delivering means in such a manner that they are freely movable or float as a unit in a plane trans-. verse to the direction of movement of the semifinished shapes so as to maintain the alignment of the gas delivering means with the bodies as they pass; to provide unitary guiding means associated with the gas delivering means whereby the gas delivering means is alwaysproperly positioned to project gas uniformly on an entire face on each side of the steel shape irrespective of any twisting and changes in contour of the steel shapes; to provide a unitary assemblage of groups of gas delivering means with common fluid distributing means so arranged and mounted that the assemblage may be quickly detached from the supporting mechanism and replaced by another assemblage; and to provide mecl. anism whereby an operator can effectively conthe operation of desurfacing successive bodies of ferrous metal at one point in a mill while the bodies are being moved in the direction of their length.

These and other objects and novel features of this invention will become apparent from the following description and the accompanying drawings. In the drawings:

Fig. 1 is a plan view of an exemplary apparatus 40 according to the present invention showing portions of a steel mill conveyor for passing successive metallic bodies, in a position to be desurfaced-on all sides simultaneously, through a desurfacing device mounted on a laterally movable carriage;

Fig. 2 is an enlarged elevational view of the desurfacing device 'shown in Fig. 1v with parts thereof broken away;

Fig. 3 is a vertical sectional view, taken on the line 3-3 of Fig. 2, showing the mechanism for providing vertical adjustment of the desur-' facing means; I

Fig. 4 is a sectional view, taken on the line 4-4 of Fig. 2, showing a blowpipe unit in position in a desurfacing head;

Fig. 5 is an elevational view, partly in section, of the laterally movable carriage, the near side supporting rail being largely broken away;

Fig. 6 is a sectional view, taken on the line 6-6 of Fig. 5;

Fig. 7 is a fragmentary view of a'post with parts broken away showing an alternative arrangement of counterbalancing means;

Fig. 8 is a front elevational view of the right half of the desurfacing device showing the arrangement of the manifolds and conduits for supplying fluid to the desurfacing heads; and

Fig. 9 is a side elevational view of the right half of the device showing the-fluid supplying conduit arrangement.

In the practice of the present invention, successive bodies of ferrous metal moving in the direction of their length may be desurfaced during or subsequent to rolling operations in a steel mill and while they are at an elevated red heat or rolling temperature. When operating on billets or the like which have a substantially symmetrical cross-section, this may be accomplished at a desired point in a mill by progressively applying wide oxidizing gas streams obliquely against and lengthwise of all sides of the body simultaneously in such a manner as to remove a stratum of metal progressively from successive portions of each of such sides.

Referring to Fig. 1 of the drawings; the desurfacing apparatus A may form a unitary part of a steel rolling mill for processing and conditioning of semi-finished steel shapes. In existing steel plants, the improved desurfacer may be substituted for a section of a conveyor of a continuous rolling mill, and the conveyor sections B and C immediately ahead of and behind the desurfacer can be placed under the control of a single operator who also controls all of the operating mechanism of the desurfacing apparatus.

As diagrammatically shown in Fig. 1, the two conveyor sections B and C at the entering and leaving sides of the desurfacer A may comprise a plurality of supporting bearings II) in which are journalled rollers II for supporting and for moving successive ferrous metal bodies, such as square prismatic steel billets D, from a blooming mill or stand of rolls of a. continuous rolling mill past the conditioning apparatus A, in the direction indicated, directly to the next roll stand or to the finishing rolls of the mill. The rollers H in the conveyor sections B and C may be driven by a variable speed motor connected to a drive shaft [4 and provided with speed regulating means not shown. As shown, each roller II is connected through bevel gears l2 and ill to a main drive shaft H carried by bearing Ii. An operator platform which carries the control mechanism for both the conveyor motors and'the desurfacer device A, hereinafter to be described, is provided and located, so that an operator can readily observe the progress of desurfacing and the condition of the desurfaced billets as they leave the desurfacer.

The desurfacer A comprises oxidizing gas vdeliver-ing means constructed and arranged to simultaneously desurface in a single pass the four sides of each of the billets D. Thus, the apparatus A thermally conditions the entire peripheral surface of each billet. The billet, when square, is preferably supported in a diamond position, that is, with a diagonal of its cross section substantially vertical. This socalled diamond position permits a great simplification of the machine as will appear in the detailed description. Four desurfacing heads E may then be supported and moved as two unitary pairs, thereby eliminating the need of more than two head-moving devices. The diamond position furthermore permits the heads E and associated fluid distributing connections to be moved toward and away from the billet surfaces in a horizontal direction which is advantageous, since any other direction of movement would involve greater complication of apparatus, particularly when the desurfacing device A is to be movable out of alignment with the conveyors B and C. A further advantage of the diamond position results from the action of gravity on the flow of slag ahead of the heads E whereby excessive amounts of slag readily flow off to each side of the billet. To maintain the diamond position of the body, the conveyor rollers H are provided with flanges I6 and I! having inwardly beveled faces l8 for contacting the adjacent lower sides of the billet so as to maintain it is alignment and in the desired position. The weight of the billet will, therefore,.keep its axis in horizontal perpendicular relation to the axes of the rollers H so as to move in a straight line. The oxidizing gas delivery means, as best shown in Figs. 1, 2, and 4, may consist of four spaced and opposed desurfacing heads E, each carrying a row of blowpipes 20 and their nozzles 2| disposed adjacent the four sides of the billets to be desurfaced. As shown in Fig. 1, the blowpipes are removed from the heads E, but in Figs. 2 and 4 they are shown mounted in the heads E. Each nozzle 2| has a central passage for delivering a comparatively large volume of oxidizing gas, such as oxygen, which is discharged from the nozzle oriflce desirably substantially at atmospheric pressure and impinges obliquely against the surface at a velocity desirably between about 200 to 1000 feet per second. However, higher dischargepressures and velocities may be em ployed under some conditions. A plurality of orifices may surround the central oxygen passage and deliver a combustible gas mixture, such as a mixture of oxygen and acetylene, to provide high temperature heating jets. The nozzles are arranged at an acute angle, preferably between 10 to 35 degrees, to the surfaces operated upon; and the individual gas streams are delivered in the general direction of the desurfacing operation.

The blowpipes 20 to which the nozzles 2| are detachably secured are rectangular in cross section and relatively narrow as compared with their width so that, when they are assembled.

adjacent to each other in the head E, as shown in Fig. 2, the nozzles are relatively close to each other and the adjacent gas stream merges on the surface to provide in effect a single gas stream which extends across the entire width of each of the sides operated upon. The nozzles 2| are arranged and supported in the head E to provide closely adjacent gas streams inclined to-.

of nozzles produce a series of very shallow parallel contiguous channels on the surface after the defects therein have been removed. Such surface is well adapted for further rolling treatment; however, if it is desired to provide level surfaces, the row of nozzles may be replaced by suitable nozzle means which produces a uniform sheet-like stream of oxygen.

The head E is in the form of a heavy box-like protector or shoe for the blowpipes and substantially encloses them on all sides except the top where the supply conduits are connected. Such shoe is described in the copending application of J. H. Bucknam, Serial No. 139,030. The connections on the upper portion of each blowpipe include a cooling water inlet 22, a water outlet 23, a fuel gas inlet 24, an inlet for'heating oxygen and an inlet 26 for oxidizing gas or desurfacing oxygen. The width of the head E is varied to suit the width of surface to be treated, the number of blowpipes and nozzles in the head being varied accordingly; for example, when desurfacing an eight inch wide face, seven nozzles are provided. The blowpipes are retained by suitable.

means, such as the retaining bars 21, secured to each blowpipe and which have pins 28 extending from their lower ends for engagement with sockets in the lower portion of the head E. The upper portions of the bars 2l have ears 29 fastened to the upper edge of the back portion 30 of the head by screws 3|. The forward portions of the blowpipes are retained by a cross bar 32 to which they are held in side by side relation by pins 33. The ends of the cross bar 32 are secured to the side walls of the shoe by screws 33'. The nozzle portions are retained in a desired fixed relation by the front wall 34 of the head E which is removable and which secures the nozzles 2| between it and the bottom 35 of the head. The bottom 35 of the head rides on the surface of the billet D and to prevent excessive wear is provided with a layer of hard surfacing metal 36. In Fig. 2 the heads on the left have their front walls 34 removed to expose the blowpipes and indicate the toeing in relation of the nozzles.

The heads E are mounted in fixed relation upon two Yshaped plates 31 by screws indicated at 36. The two arms of each Y are arranged at 90 to each other and the heads are arranged to have the bottoms 35 at 90 to each other and at 45 to the horizontal and vertical diagonals of the billet so as to contact two adjacent sides of the billet simultaneously. The stem portions 39 of the Y plates are afiixed by a large screw 40 to the horizontally movable slides 4 l. The two slides 4| are movably mounted on a pair of brackets 42 so that the slides and the parts carried thereby can be maintained either in an operative position with the layers of hard surfacing metal 36 of the heads E bearing against the sides of a billet, or in a non-operating position with the heads E spaced a considerable distance from such sides. To accomplish this, the upper portion of each bracket 42 is U-shaped in section, as shown in Fig. 3, and in the spaced arms at the front face of the bracket are formed grooves which receive the upper and lower flanges 43 and 44 of the slide 4|. In the space between the rear faces of the slide 4| and the front face of v the'bracket 42 is mounted a fluid actuated device, such as a hydraulic cylinder 45, and a piston 46 therein, for moving the slide along the bracket. The cylinder 45 is rigidly secured to the rear side of the slide 4|, and the piston 46 has a piston rod 41 which is resiliently connected at its outer end to an ear 46 secured to the bracket 42. The rod is slidable in the ear 48 to a limited extent determined by springs 49 between it and collars 56 on the piston rod.

Fluid delivered into the space at the rod end of the piston 46, causes the cylinder 45, slide 4|, and heads E to move away from the billet and assume a non-operating position. Conversely, fluid delivered into the space at the head side of the piston 46 causes the cylinder, slide and heads to move toward the billet so as to position the nozzles N adjacent to the sides of a billet. The springs 49 permit the heads E to move horizontally through a slight amplitude in response to small irregularities of the surface of the billet and independently of the setting of the hydraulic cylinders 45.

To adjust or limit the movement of the heads toward the billet, lugs or stops 5| may be secured to the brackets 42 at any one of a plurality of spaced holes 52, as shown in Fig. 2. Against the stops5| of the ends of threaded studs 53 are adapted to bear, the studs 53 being carried by lugs 54 secured to the slides 4|. The-stops 5| can be fixed at any one of the holes 52, depending upon the size of the billets being desurfaced, and the position of the threaded studs 53 can be accurately adjusted on the lugs 54 whereby the nozzles 2| can be properly set and maintained at their desired operating position.

The brackets 42 are preferably supported in such a manner that the heads E carried thereby are freely or universally movable in any direction in a plane transverseto the direction of movement of the billets D, so that desurfacing of billets can be readily initiated irrespective of slight variations in the position of the billets on the conveyor section B. This is accomplished, as shown in Fig. 3, by pivotally connecting the rear faces of the brackets 42 at 55 to the forward ends of horizontal plates or links 56, the rear ends of which are pivotally connected at 51 to a vertical back plate 56. Two horizontal plates 56 are associated with each bracket 42, as best shown in Figs. 1 and 3, and the ends of all four plates 56 are pivotally connected to the single vertical back plate or connecting member 58. This connecting member 58 extends transversely of the apparatus at the rear thereof and is provided with a central U-shaped opening 59, shown in dotted lines in Fig. 2', whereby the billets can freely pass through the apparatus during'desurfacing.

The back plate 58 is pivotally connected at 60 at each of its corners to the rear ends of forwardly extending horizontal links 6|, as shown in Figs. 1 and 2, and the forward ends of links 6| are pivotally connected at 62 to pedestals or posts 63 which may be secured to a base 64. The

downwardlydepending skirt portions 65 of the brackets '42 are rigidly tied together by a long horizontal tie plate .66 so that they may move in unison. The tie plate 66 is fastened by screws 61 which may be placedin certain of the several holes 66 provided therefor in the skirt 65 to adjust the separation of the brackets 42 according to the size of billet processed. With this construction the pivotally connected horizontal plates 56 permit a vertical or up and down movement of the heads E, and the pivotally connected links 6| permit a transverse movement of the heads E in unison.

In order that the heads E, slides 4| and brackets 42 will be freely movable .vertically and yet remain supported in the desired operating range, their weight is counter-balanced in a suitable manner. For this purpose the posts 88 are U-shaped in section and have brackets 88 secured to their upper ends and mounted thereon to extend upwardly and obliquely toward the front of the apparatus, as shown in Figs. 1 and 2.

To the outer ends of the brackets 58 are pivotally secured levers I0 which have clevises II and I2 pivotally connected thereto at their opposite ends. A heavy wire cable I8, depending downward from each clevis I2, is secured at its lower end at I4 to the rear face of the bracket 82; and at the other end of lever III, a piston rod I5 depends downward from each clevis II to the piston of a dash pot or air cylinder I6 mounted in the interior of each post 63. The lower endgof the cylinder I8 is hingedly attached to the bottom of the post 63 by a clevis I! to permit straight line movement of the rod I5 with respect to cylinder I6.

The counter-balancing mechanism just described is provided with steadying means which also causes the heads E to float in unison in their desired operating position. The means here preferably provided comprises an additive weight I8 in the form of a horizontal bar of cast iron provided with two flexible cables I9 attached to the upper side of the bar. The opposite ends of the cables I9 are connected to the tie plate 66 and the weight I8 normally rests upon the base plate 64. If desired, chains may be used in place of cables for greater flexibility. The length of the cables I8 is such that the weight I8 will be just touching the base 54 when the heads E are floating in the desired operative position. The pressure of the air applied to the upper portion of cylinder I6 is maintained at a constant value which. when acting on the .eflective area of the piston, exerts a force slightly in excess of that required to lift the front assemblage of the desurfacing mechanism including the heads E but not enough to lift both the desurfacing mechanism and all of the weight of the weight I8. The heads E will therefore float at the desired level and but little additional force is required to displace them above or below this level; for example,

the added force to lift the heads is equal to that part of the weight of weight I8 that is not counterbalanced by the force exerted by the cylinder I6 and may be about fifty pounds if the weight I8 weighs 100 pounds. The added force to lower the heads E from the floating position is then at least fifty pounds or that part of the weight I8 which is normally counterbalanced.

Under certain conditions, it may be inconvenient to have the weight 18 located below the heads E and other means for causing the heads to float at the desired level may be provided, such as special leveling devices in conjunction with the air cylinders I5.

An alternative arrangement is shown in Fig. '7 where a weight I8 having a central opening Ill therethrough surrounds the piston rod I5 of the air cylinder 16. The weight I8 normally is supported at about the mid portion of the rod I5 by a horizontal supporting plate III whose edges are secured to the inner side walls of the post 88. The plate III also has a hole through which the rod I5 passes and which is larger than the hole H8. To pick up the weight I8 when the rod I5 moves to a position higher than the floating level, a clamp H2 is secured on the rod I5 under the weight. The longest horizontal dimension of the clamp H2 is larger than the diameter of the hole H8 but smaller than the hole in plate ,in the machine. and very hot billets from sagging due to their III so that the clamp H2 will pass therethrough and engage weight I8. 'A weight I8 is arranged in each of the posts 63.

This arrangement operates in a manner similar to that already described except that the weights are picked up when the heads E are displaced downward from the normal level. Thus, the air cylinders together exert a force which, when aided by the two weights I8, is suflicient to raise the heads and supporting mechanism to the desired level. When this level is reached, the weights I8 touch the plates Ill so that the weights no longer aid the cylinders. The air pressure is maintained at such a constant value that the force exerted is not enough to raise the heads E above the desired level without the aid of the weights I8. The heads E will therefore always return to the desired normal level when displaced therefrom.

To support the billet as it passes through the desurfacing apparatus, an idler roller 88 is provided immediately behind the heads E. The roller is supported by a bearing stand 8| mounted upon the base 6|. If desired, motor means may be provided for positively driving the roller 80, for example, when very short bodies are to be desurfaced which otherwise might stall The idler roll 80 prevents long weight and softness.

The base plate 64 of the desurfacing apparatus forms part of a carriage for moving the apparatus to and from the operating position. The carriage indicated generally at F is shown in greater detail in Figs. 5 and 6 and comprises a horizontal box-like frame 82 supporting base plate 64. The frame-is supported by two transverse axles 83, journalled in bearings 84 mounted in the side walls of the frame. Flanged wheels 85 are carried by the end portions of the axles ,for tracking on a pair of rails 86 which are disposed perpendicular to the centerline of the conveyors B and C and supported upon a foundation having a trough-shaped depression 87 between the rails. Means for moving the carriage horizontally along the rails is provided and preferably actuated by an electric motor indicated at 88. The motor 88 is coupled to a horizontal shaft 89 longitudinally. supported centrally under the frame 82 by bearings 98. Below each axle, a worm 9| is keyed to the shaft 89 so as to intermesh with the teeth of a worm gear 92 which is keyed to and mounted centrally on each axle 83. The motor, being reversible, is thus geared to both axles so as to drive the carriage in either direction. Stops are provided to definitely limit the travel in each direction and arranged to hold the carriage rigidly down on the rails when in the extreme positions. These comprise brackets 93 depending downwardly from the under side of the frame 82. These brackets have arms 94 extending horizontally toward each other which hook under a horizontally projecting bracket 85 attached to the side wall of the trough 8I. Switching means for automatically slowing down and stopping the motor 88. are also provided and operated by means of two sets oi cams 98 and 91 carried by the base 84 at one side thereof. The cams engage and lift followers 98 and 89 when the carriage F approaches an end position at first to slow down the motor and then stop it. With one follower up the motor is slowed down and with both held up it is stopped and the motor control conditioned for movement in the reverse when desired. The

followers and switch mechanism are carried by a flxed housing I00. The motor 88 is supported by a bracket IOI extending from the end of the frame 82. v

When the desurfacing apparatus is moved to the inoperative position, it is desirable that a supporting roller be substituted for the roller 80. The substitute roller I02 is substantially identical to the rollers II and may be without driving means, although a motor may be connected thereto if desired for positively driving the roller. The roller I02 is journalled in bearings I03 supported upon the base 64 alongside of the desurfacing apparatus A. The stops 93 for the carriage F are so located with respect to the bracket 95 that the roller I02 will be aligned with the conveyors B and C at one extreme position of the carriage and the heads E and roller 80 will be aligned with the conveyors B and C in the other extreme position as shown in Fig. 1.

The arrangement of unitary means for sunplying gas and cooling liquid to each of a pair of heads E is shown in Figs. 8 and 9. Only the right half of the desurfacing device A is here shown and described, since the left half is a mirror image thereof. The fluid distributing assemblage for a pair of heads comprises a set of five vertically disposed manifolds H4, H5, H6, H1, and I I8 which are secured side by side in a row on a holder H9. The holder H9 has the form of a hollow vertical rectangular prism, the manifolds being secured by welding at their mid portions to the outside wall thereof. The inside wall of holder I I9 is provided with a flange I extending from one side toward heads E by which the holder and assemblage is secured to the Y plate stem 39 by two cap screws I 2|.

The upper and lower end portions of manifolds H4, H5, H6, H1, and H8 are each provided with as many connections I 22 as there are blowpipes in a head E. The end portions of the manifolds are also bent at a 45 degree angle toward the corresponding head E so that conduits I23 provided between the blowpipes 20 in each head E and the connections I22 may be conveniently arranged and those of each row may be of equal length. The conduits I23 are arranged so that each connection I22 on manifold II8 communicates with the fuel or heating gas inlet 24 of a blowpipe 20, the manifold II8 therebv distributing heating gas. The connections I22 of manifold II'I communicate through another set of conduits I23 with the heating oxygen inlet 25 of each blowpipe. Manifold I I6 is similarly connected to the water inlets 22; manifold H5 is similarly connected to the oxidizing as or desurfacing oxygen inlets 26; and manifold H4 is similarly connected by the rearmost set of conduits I23 to the water outlets 23. The conduits I23 need not be flexible, since the heads E and corresponding manifolds are mounted in fixed relation to each other on the Y plate stem 39. providing an assemblage that moves as a unit.

To permit movement of such assemblage, the supply conduits conducting fluid to or from the manifolds H4, H5. H5, H1, and Bare arranged to be flexible and have downwardly depending loop portions. Thus, flexible conduit I24 conducts used cooling water away from manifold II 4 being connected thereto below its mid portion. Similarly, conduit I25 conducts oxidizing gas or desurfacing oxygen to manifold II 5 to which it is connected at a point above conduit I24; conduit I26 supplies cooling water to the manifold II6, to which it is connected at its mid point; conduit I2I supplies heating oxygen to conduit 1, being connected thereto at a point above conduit I26; and a conduit I28 supplies heating gas to conduit H8 and is connected thereto above conduit I2'I.

Each of these flexible conduits I24, I25, I26, I21, and I28 communicates with control apparatus located within a housing I29 which is disposed adjacent and to the rear of the post 63. The-control apparatus in housing I29 may be operated by remote control means from an operators station. At the operators station, such remote control means may preferably be interconnected with the conveyor motor controls and the cross carriage motor controls so that the flow of gases and cooling water may be started and stopped at the proper times and in the desired sequence. Thus, when the heads E are moved away from the billet D, the flow of gases to the blowpipes may be shut oil? and started again in the proper sequence when the heads E are moved toward 'the billet. The flow of fluids may be similarly shut off when the carriage F is moved to carry the desurfacing device A out of alignment with the conveyor.

When the desurfacing mechanismis in the operative position to desurface successive billets being delivered thereto upon the conveyor B, with air pressure constantly applied to the cylinders 16 so that the heads E float in the operative position and are held apart by hydraulic pressure in the rod ends of the cylinders 45, the driving mechanism of conveyor B is controlled to move the end of the billet between the heads E and bring it to rest in a position so that its forward end is within 3 to 5 inches beyond the plane of the ends of the nozzles 2I. pressure is applied to the head ends of the cylinders 45 to move the heads E into contact with the four sides of the billet. The preheating flames are then turned on and when the surface is at the ignition temperature the oxidizing gas is applied and the conveyors B and C started. The billet then is driven through the heads E with comparatively little resistance and has its four sides simultaneously desurfaced'except for the short forward end portion which is cropped off at another point in the conveyor line. If the billets are not to be crr oped, the desurfacing-is initiated at the extreme end by stopping the billets with the end close to the orifices of the nozzles. Suitable mechanism for accurately stopping the billets in such a position with relation to the heads E may be provided if desired. Such mechanism may comprise an electrical means that provides short impulses to the driving motor of the conveyor B such that the billet may be inched forward or backward by a series of short movements. As soon as the rear end of the billet reaches the heads E after passing through the desurfacer, the gases are turned off and the heads separated so that another billet may be brought into position and desurfaced.

The high temperature heating jets and relatively voluminous oxidizing gas streams discharged from the nozzles 2I impinge obliquely against and merge on the surfaces'across their entire widths, the oxidizing gas reacting with the heated surface metal and causing it to ignite and burn. This burning or oxidation of surface metal takes place progressively as successive portions of heated surface metal are subjected to the influence of the oxidizing gas, a continuous reaction zone or puddle being con- Hydraulic stream forces away the oxidized and molten surface metal from the reaction zone, and this mixture has been termed a "slag" Although surface metal can be reduced completely to an oxidized form, it has been found in practice that a portion of the surface metal can be removed while in a. partially oxidized state and another portion in an unoxidized state and molten form, thus effecting considerable economy in the amount of oxidizing gas consumed. The puddle is retained on and confined centrally on each surface by inclining the outer nozzles of each row slightly toward the central nozzles. This provides components of force of the outer streams which tend to urge the reaction puddle to a central position in and ahead of the reaction zone. The slag is thus able to impart more heat to the portions of the billet to be desurfaced and excessive erosion of the corners of the billet is avoided. This principle is more fully disclosed in Patent No. 2,157,095.

Since the heads E ride in contact with the four sides of the billet, it will be seen that any slight change in thickness of the billet will cause the pairs of heads to be moved horizontally against the pressure of the springs 49 and any variation in straightness of the billet or lateral camber will cause the heads E to move up or down or horizontally in unison so as to maintain contact without causing binding or material resistance to the passage of the billet. Since the weight of the desurfacing apparatus is almost completely counterbalanced, the pressures on the heads E necessary to cause the transverse movements are small.

After the billet is completely desurfaced, it

leaves the apparatus A upon the power driven conveyor section C, and, since considerable heat is soaked into the billet during desurfacing and especially where this desurfacing is effected just ahead of the next roll stand, the successive billets are at an augmented hot rolling temperature and pass immediately to these finishing rolls without the possible necessity of placing the billets in reheating furnaces. The flanges I6 and H of the rollers H of both conveyor sections B and C, as well as the idler roller 80, are in alignment and cooperate to guide the billet in a straight path during its passage through the space defined by the desurfacing heads E.

Where the present desurfacing apparatus is to be substituted for a section of billet conveyor line in an existing rolling mill, the desurfacer A may be located so close to a stand of rolls that the billet enters the rolls, which have a diamond shaped opening, while it is still passing through the desurfacer. For example, the roll stand may be in the position occupied by the conveyor section C. In such cases the speed of movement of the billet through the apparatus will be fixed by the speed of the rolls and factors such as the angle of the nozzles and gas velocity are selected to give the desired depth of cut when the hot billets move at the predetermined speed. This is possible in the present device, since the rate a reaction on hot billets with p qper control of the factors mentioned is very high so that the billet can move relatively fast.

When it is desired to pass a billet through the roll stands without surface treatment, or where it is desired to pass along the conveyor line a body of a different size or shape than will pass through the heads E, the desurfacer A is quickly moved out of alignment with the conveyor B and the roll 102 is moved into alignment by energizing the motor 88 of the carriage F. The electrical controls for the conveyor B and motor 88 are interlocked so that billets on conveyor B cannot move while carriage F is moving in order to insure against injury to the apparatus. When the motor 88 is energized the carriage F moves at a rapid rate until slowed down by the engagement of either cam 88 with the respective contactor and stopped by the lifting of the respective second contactor and the engagement of either one of stops 93 with the bracket 85. The cams and stops are so located that the roll I02 or the heads E are in accurate alignment with the conveyors B and C as desired. Shapes, such as slabs of rectangular section, may be conveyed by the cy drical portions of the rolls II and roll I02.

If desired, another desurfacing device, similar to the device A but having heads similar to heads E adapted to desurface billets of different shape or dimensions, may be mounted on the carriage F in place of the roll I02. Such an arrangement permits two varieties of billets to be desuri'aced in the conveyor line of a mill which processes more than one variety. The change can be made with very little interruption of the movement of the steel shapes.

It is also proposed, according to this invention, that an assemblage of two heads E mounted to move in unison together with means for distributing gas to the nozzles of each head, such assemblage being arranged to be supported for lateral movement with respect to a body to be operated upon, may be used to remove the surface irom two adjacent sides only of the body. The two heads E'are then also mounted in the same angular relation to each other as the angular relation between the adjacent surfaces, for example, if the body is rectangular, the heads should be perpendicular to each other. If the body to be desurfaced is polygonal, having more than four sides, one head for each side to be treated may be provided and mounted to move in unison to and from those surfaces which are all on one side of a plane through the axis of the body. Where round bars are to be treated, the heads E may be arcuate to correspond to the cylindrical surface and the segmental heads on one side of the axial plane of the cylindrical surface may be mounted to move in unison to and from the surface. Where sides on one half only of the body are to be desurfaced, the body may be supported so that these surfaces are upward and the heads may move vertically to and from the surfaces.

Obviously, certain features of the invention may be used independently of others and changes may be made in various parts of the apparatus without departing from the essentials of the invention. For example, although the hereindisclosed process and mechanism are especially adapted for conditioning or desurfacing semi-flnished square steel shapes while they are at a red heat and in transit between successive rolling operations, it will be understood that the same principles are applicable to the desurfacing of billets, blooms, etc., which are taken from stock and are cold or at ordinary atmospheric temperature, and to the conditioning of part or all of the longitudinal surface portions of round, polygonal and other shapes. Furthermore, other types of blowpipes may be employed to progressively apply wide streams of oxidizing gas obliquely against and lengthwise of the longitudinal surfaces undergoing treatment.

We claim:

1. A process of thermo-chemically removing surface metal from an elongated metal body, such as a steel billet, having a polygonal cross-sectional shape, which comprises progressively applying a stream of oxidizing gas obliquely against and lengthwise of a longitudinal surface of said body while said surface is maintained in an inclined position relatively to a horizontal plane.

2. A process of thermo-chemically removing surface metal from an elongated metal body, such as a steel billet, having a rectangular shape, which comprises simultaneously applying streams of oxidizing gas obliquely against and progressively along all four longitudinal surfaces of said body while such surfaces are inclined to a horizontal plane.

3. A process of conditioning an elongated multi-sided metal body, such as a steel billet, which comprises hot rolling said .body in successive steps; propelling said body in a heated condition from one of such rolling steps to the next rolling step while maintaining at least two of its longitudinal surfaces inclined relatively to a.

horizontal plane; and applying streams of oxidizing gas obliquely against and lengthwise of such inclined surfaces during such propulsion between rolling steps, to remove surface metal from said inclined surfaces.

4. A process of conditioning an elongated metal body, such as a steel billet, having a square crosssectional shape, which comprises hot rolling said body in successive steps; propelling said body in a heated condition from one of such rolling steps to the-next rolling step while maintaining all four of its longitudinal surfaces inclined relatively to a horizontal plane through one of the diagonals of the square cross section; and applying a stream of oxidizing gas obliquely against and lengthwise of each of such/inclined surfaces during such propulsion between such rolling steps, to remove surface metal from each of said surfaces.

5. A process of removing surface metal from an elongated metal body, such as a steel billet, having a substantially square cross-sectional shape, which comprises simultaneously applying streams of oxidizing gas obliquely against and progressively lengthwise of all four longitudinal surfaces of said body while one of the diagonals of such square cross section is perpendicular to a horizontal plane and all of such surfaces are cross-sectional shape, which comprises propelling and guiding said body horizontally in the direction of its length while maintaining all four longitudinal surfaces of the body inclined to a horizontal plane passing through one of the diagonals of said square shape; providing four devices for delivering wide streams of oxidizing gas; arranging said devices in inclined positions and respectively substantially parallel to such four inclined longitudinal surfaces of said body; and simultaneously applying said streams obliquely against and lengthwise of said surfaces, respectively, while said body is propelled and guided in the direction of its length.

8. A process of removing surface metal from an elongated metal body, such as a steel billet having a polygonal cross sectional shape,, whichcomprises applying an oxidizing gas stream to each of two adjoining longitudinal surfaces of said body, said streams being each applied obliquely against and lengthwise of the respective surface; relatively moving said body in the direction of its length with respect to said streams and against the general direction of flow of said streams; maintaining the relation between streams acting on adjacent surfaces fixed; streams in unison and laterally of said body in response to variations of the surface thereof during such relative movement to maintain uniform removal of surface metal from said surfaces irrespective of variations thereof.

9. A process of removing surface metal from an elongated metal body, such as a steel billet having a polygonal cross sectional shape, which comprises applying an oxidizing gas stream to each of the longitudinal surfaces of said body, said streams being each applied obliquely against and lengthwise of the respective surface; relatively moving said body in the direction of its length and against the general direction of flow of said streams; maintaining a fixed relation between the streams acting on the surfaces of said body which are disposed on one side of a plane containing the longitudinal axis of the body; maintaining a fixed relation between the remainder .of said streams; and moving the streams maintained in such fixed relation in unison and laterally of said body in response to variations of the surface thereof during such relative movement to maintain uniform removal of surface metal from all surfaces of said body irrespective of variations thereof. r

10. A process of desurfacing a ferrous metal body which comprises supporting said body in a position to be desurfaced on all its longitudinal sides, maintaining portions of surface metal to be removed at the ignition temperature, progressively applying wide streams of oxidizing gas at an acute angle simultaneously on each of the longitudinal surfaces of said body to remove surface metal from all such sides in one pass, and varying the position of all of said stream applying means relatively to said body in unison in response to variations in the condition of said surfaces whereby a substantially uniform stratum is removed from all sides irrespective of variations in the shape and straightness of portions of the body.

11. A process of desurfacing a ferrous metal body while said body is at an elevated temperature and in transit between successive hot rolling operations which comprises propelling and guiding said body in a position with respect to desurfacing heads for surface treatment on all longitudinal sides with oxidizing gas projected from said heads and with said sides inclined to a horiand moving said zontal plane; interrupting the movement of said body when an end thereof is adjacent said heads; projecting a heating flame on all the longitudinal surfaces of said body from said desurfacing heads to initiate such treatment; and then progressively applying wide streams of oxidizing gas on all longitudinal sides of said body from said heads to remove surface metal therefrom.

12. A process of conditioning an elongated multi-sided metal body such as a steel billet which comprises hot rolling said body; propelling said body lengthwise with its lateral sides inclined to a horizontal plane and at a substantially uniform speed; applying streams of oxidizing gas obliquely against and lengthwise of each lateral side to remove a layer of surface metal from the entire perimetral surfaces; and hot rolling the desurfaced portions of said body during the application of said oxidizing gas streams to portions of the body from which surface metal has not yet been removed whereby the rate of rolling determines said speed.

13. Apparatus for desurfacing an elongated metal body such as a steel billet comprising the combination of means for supporting and .propelling said body in the direction of its length; a plurality of desurfacing heads disposed adjacent the longitudinal surfaces of said body when so propelled, the number of heads being sufficient to desurface all said surfaces in one pass; each head being adapted to project a wide stream of oxidizing gas lengthwise of and at an acute angle to a longitudinal surface of said bilet; means connecting said heads in unitarily movable groups: and mechanism for supporting and adjusting said' groups transversely with respect to said body.

14. Apparatus for removing surface metal from a metal body, such as a steel billet, which comprises means for supporting and propelling said body lengthwise with its longitudinal sides maintained inclined to a horizontal plane; two pairs of blowpipe units, each unit being adapted to project a wide stream of oxidizing gas at an acute angle to and lengthwise of a longitudinal surface of said body when so propelled; means for rigidly connecting together the units of each pair of units; and means for moving said pairs of units toward and away from the surfaces of said body.

15. Apparatus for thermo-chemically removing surface metal from a metal body, such as a steel billet, which comprises a pair of blowpipe units disposed at an angle to one another; means for effecting simultaneous relative movement between said body and said blowpipe units in directions along adjoining longitudinal surfaces of said body and parallel to the intersection of said surfaces, said blowpipe units being positioned and adapted simultaneously to apply streams of oxidizing gas obliquely against and lengthwise of said surfaces, andmeans for moving said units in unison toward and away from said surfaces in a direction having substantially the same relation to both surfaces.

16. Apparatus for thermo-chemically removing surface metal from a metal body, such as a steel billet, which comprises two pairs of blowpipe units; means for rigidly connecting together the units of each pair of units and maintaining said units positioned for projecting streams of oxidizing gasobliquely against and lengthwise of adjoining longitudinal surfaces of said body; and means for moving said pairs of units in unison toward and away from the surfaces of said body.

17. Apparatus for removing surface metal from a metal body as claimed in claim 16 which includes a common means rigidly connected to each pair of units for supplying and distributing gas to each unit of the respective pair, and flexible conduit means for supplying gas from a source of supply to each gas distributing means.

18. In apparatus for desurfacing a metal body such as a steel billet, the combination comprising horizontally and vertically adjustable heads for directing an oxidizing gas stream at an acute angle to and lengthwise of each longitudinal surface of said body; means for effecting relative movement between said heads and said body longitudinally of said body; members for supporting said heads for vertical and horizontal movement transversely of said body; said heads being movable along said members toward and away from the surfaces of the body to be treated; and mechanism connected to both a head and the member supporting it for moving the head along its supporting member through a relatively wide range of movement including means for resiliently urging the heads toward said surface operative through a shorter range;

19. 'Thecombination with a machine for applying streams of oxidizing gas obliquely against and lengthwise of the longitudinal surfaces of metal bodies, such as steel billets, to remove surface metal from said surfaces; of means for conveying such bodies in the direction of their length through said machine and past said streams; mechanism for moving said machine into and out of operative position relatively to such conveying means; and a conveyor element movable by said mechanism into position to replace said machine when said machine has been moved out of its operative position relatively to said conveying means.

20. Apparatus for conditioning rectangular elongated bodies, such as steel billets, which comsage being defined by means for projecting a relatively voluminous stream of oxidizing gas on a band of surface metal completely engirdling said body, and a set of rolls having a diamond shaped opening therebetween in alignment with said passage for reducing the cross section of said body after surface treatment with oxidizing gas.

21. The combination with a rolling mill having a conveyor line provided with a surface conditioning station, of a surface conditioning unit for thermo-chemically surface treating semi-finished steel articles in said conveyor line, said unit being normally in alignment with said conveyor line, and remotely controlled means for transferring said unit across said conveyor line to a position out of alignment with said conveyor line.

22. The combination with a rolling mill having a billet conveyor line provided with a billet thermal-conditioning station of a-four-sided billet thermal-conditioning unit having a diamond shaped passage at said station, and billet conveyor means coacting with said thermal-conditioning unit to steady and guide the billets through the diamond-shaped passage in said unit.

23. The combination with a steel rolling mill having a billet conveyor along which the billets move in a diamond shaped position, said conveyor line being provided with a thermo-chemical billet treating station, of a transverse way at said station, a carriage movable along said transverse way, a billet surface conditioning unit and an idler roll associated with said carriage, and means for positioning said carriage on said way to bring either said billet conditioning unit or said idler roll into operative relation with said conveyor line.

24. The combination with a billet rolling mill having a conveyor line provided with a billet conditioning station, of billet conditioning means adapted to act thermo-chemically upon all sides of the billet at one pass, said billet-conditioning means being supported for floating movement in a plane transverse to said conveyor line, and means associated with said billet-conditioning means and controlled by the sides of the billet for maintaining'said billet-conditioning means in properly spaced relation to the billet as it passes therethrough.

25. Apparatus for surface conditioning an elongated metal body, such as a steel billet, com prising the combination of means for supporting and propelling said body in the direction of its length; a plurality of blowpipe heads disposed adjacent the longitudinal surfaces of said body vwhen so propelled,,the number of heads being suflicient to condition all said surfaces in one pass; each head being adapted to project gas on a region extending completely across a longitudinal surface of said billet; means connecting said heads in unitarily movable groups; and mechanism for supporting said groups of heads and for causing said groups of heads to move in unison in response to variations in the dimensions and straightness of successive portions of said body when propelled to pass' adjacent said heads.

26. Apparatus for surface conditioning an elongated metal body, such as a steel billet, comprising the combination of means for supporting and propelling said body in the direction of its length; a plurality of blowpipe heads disposed adjacent the longitudinal surfaces of said body when so propelled, the number of heads being sufllcient to condition all said surfaces in one pass; each head being adapted to project gas on a region extending completely across a longitudinal surface of said billet; means connecting said heads in two unitarily movable groups; mechanism for adjustably supporting said groups of heads; and means for moving said groupstoward and away from each other.

27. Apparatus for surface conditioning an elongated metal body, such as a steel billet, 'comprising the combination of means for supporting and propelling said body in the direction of its length; a plurality of blowpipe heads disposed adjacent the longitudinal surfaces of said body when so propelled, the number of 7 heads being sufficient to condition all said surfaces in one pass; each head being adapted to project gas on a region extending completely across a longitudinal surface of said billet; means connecting said pendicularly to one another; means for effecting simultaneous relative movement between said body and said blowpipe units in directions along adjoining longitudinal surfaces of said body and parallel to the intersection of said surfaces; said blowpipe units being positioned and adapted simultaneously to apply streams of gas against said surfaces; and means for moving said units in unison toward and away from said body.

' 29. Apparatus for removing surface metal from a metal body, such as a steel billet, which comprises a pair of blowpipe units disposed at an angle to one another; means for eifectingsimultaueous relative movement between said body and said blowpipe units in directions along adjoining longitudinal surfaces of vsaid body and parallel to the intersection of said surfaces; said blowpipe units being positioned and adapted simultaneously to apply streams of oxidizing gas obliquely against and lengthwise of said surfaces; means for moving said units in unison toward and away from said body; said units each comprising a row of blowpipe nozzles, each nozzle being adapted to deliver a jet of oxidizing gas; and said nozzles being disposedso close to each other that the jets of oxidizing gas therefrom merge, whereby two unitary wide streams are delivered by said units.

30. Apparatus for surface conditioning a metal body, such as a steel billet, which comprises a pair of blowpipe units disposed at an angle to one another; means for effecting simultaneous relative movement between said body and said blowpipe units in directions along adjoining longitudinal surfaces of said body and parallel to the intersection of said surfaces; said blowpipe units being positioned and adapted simultaneously to apply streams of gas against said surfaces; means for moving said units in unison toward and away from said body; said units being rigidly connected to one another; and single means for moving said units in unison toward and away from the longitudinal surfaces of said body.

31. Apparatus for surface conditioning a metal body, such as a steel billet, which comprises a pair of blowpipe unitsdisposed at an angle to one another; means for effecting simultaneous relative movement between said body and said blowpipe units in directions alongadjoining longitudinal surfaces of said body and parallel to the intersection of said surfaces; said blowpipe units being positioned and adapted simultaneously to apply streams of gas against said surfaces;

means for moving said units in unison toward and away from said body; one of said units being one another; means for-effecting simultaneous relative movement between said bodyand said blowpipe units in directions along adjoining longitudinal surfaces of said body and parallel to the intersection of said surfaces; said blowpipe units being positioned and adapted simultaneously to apply streams of gas against said surfaces; means for moving said units in unison toward and away from said body; and means for moving said units vertically in unison to align them simultaneously relatively to said surfaces.

33. Apparatus for surface conditioning a metal body, such as a steel billet, which comprises a pair of blowpipe units disposed at an angle to one another; means for effecting simultaneous relative movement between said body and said blowpipe units in directions along adjoining longitudinal surfaces of said body and parallel to the intersection of said surfaces; said blowpipe units being positioned and adapted simultaneously to apply streams of gas against said surfaces:

means for moving said units in unison toward and away from said body; means rigidly connecting said units; and a vertically and horizonv tally adjustable support for said connecting means and units.

34. Apparatus for surface conditioning a metal body, such as a steel billet, which comprises a pair of blowpipe units disposed at an angle to one another, means'for effecting simultaneous relative movement between said body and said blowpipe units in directions along adjoining longitudinal surfaces of said body and parallel to the intersection of said surfaces; said blowpipe units being positioned and adapted simultaneously to apply streams of gas against said surfaces; means for moving said units in unison toward and away from said body; and unitary means for distributing and supplying gas to each of said units; said units being rigidly connected to one another and to said gas supplying means.

35. Apparatus for thermally surface conditioning a metal body, such as a steel billet, which comprises a pair of blowpipe units disposed at an angle to one another; means for effecting simultaneous relative movement between said body and said blowpipe units in directions along adjoining longitudinal surfaces of said body and parallel to the intersection of said surfaces, said blowpipe units being positioned and adapted simultaneous- 1y to apply streams of gas against transverse zones of said surfaces, and means for moving said units in unison toward and away from said 36. Apparatus for thermally surface conditioning a metal body, such as a steel billet, which comprises two pairs of blowpipe units; means rigidly connecting together the units of each pair of units and maintaining said units positioned for projecting streams of gas against transverse zones of adjoining longitudinal surfaces of said body; means for moving said pairs of units in unison toward and away from the surfaces of said body; and means for causing said units .to float normally at a desired level and tend to return to that level when displaced therefrom.

37. Apparatus for thermally surface conditioning a metal body, such as a steel billet, which comprises two pairs of blowpipe units; means rigidly connecting together the units of each pair of units and maintaining said units positioned for projecting streams of gas against transverse zones of adjoining longitudinal surfaces of said body; means for moving said pairs of units in unison toward and away from the surfaces of said body; pneumatic means for counterbalancing and raising said units to a desired level when displaced below said level; and means effective only when said units are above the desired level tending to move them down to said level when displaced thereabove.

38. Apparatus for thermally surface conditioning a metal body, such as a steel billet, which comprises two pairs of blowpipe units, means rigidly connecting together the units of each pair of units and maintaining said unitspositioned for projecting streams of gas against transverse zones of adjoining longitudinal surfaces of said body; means for moving said pairs of units in unison toward and away from the surfaces of said body; pneumatic means for counterbalancing a major portion of the weight of said blowpipe units and associated mechanism; and means eifective only when said units are below a desired level for moving them up to said level.

39. Apparatus for thermally surface conditioning a metal body, such as a steel billet, which comprises two pairs of blowpipe units; means rigidly connecting together the units of each pair of units and maintaining said units positioned for projecting streams of gas against transverse zones of adjoining longitudinal surfaces of said body; means for moving said pairs of units in unison toward and away from the surfaces of said body; a common means rigidly connected to each pair of units for supplying and distributing gas to each unit of the respective pair; and flexible conduit means for supplying gas from a source of supply to each distributing means.

40. The combination with a rolling mill having a conveyor line provided with a surface conditioning station, of a plurality of surface conditioning units for thermo-chemlcally surface treating semi-finished articles in said conveyor line, said units being normally out of alignment with said conveyor line, and remotely controlled means for transferring any one of said units across said conveyor line to a position into alignment with said conveyor line.

41. The combination with a rolling mill having,

a conveyor line provided with a surface-conditioning station, of a blowpipe unit, a frame movable transversely of said conveyor line and normally disposed at said station in a position adapted to operatively support said blowpipe unit for surface conditioning a steel article carried by said conveyor line, and remotely controlled means for moving said supporting frame and said blowpipe unit thereon bodily across said conveyor line into and out of operative alignment with said conveyor line.

HOMER. W. JONES.

JANE H. BUCEIAM.

EDMUND A. DOYLE.

. CERTIFICATE OF CORRECTION.

Patent No. 2,210,921. August 15, 191 0.

HOMER w. JONES, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 2, second column, line 214., for the word "is" read -inline 61, for "stream merges" read "streams merge--; page 5, second column, line 25, strike out "of" first occurrence; page 6, first column, line 12, after "slag" insert a period; page 8, first column, line 55, claim 15, for "bilet" read "billetand second column, line 69, claim 25, after "conveyor" insert the word --1ineand that the said Letters Patent should be read with this correction there-- in that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21th day of September, A. D. 19110.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

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