US3503161A - Method of treating a continuously cast billet - Google Patents

Description

March 31, 1970 B. E. LONG 3,503,161

METHOD OF TREATING A CONTINUOUSLY CAST BILLET Filed Sept. 29, 1967 3 Sheets-Sheet l March 31, 1970 B. E. LONG 3,503,161

METHOD OF TREATING A CONTINUOUSLY CAST BILLET Filed Sept. 29, 1967 5 Sheets-Sheet 2 1 30. 1!: t i r: l {i INVENTOR. w a 34 BYRNS E. LONG 3| 32 1 E Z S p 37 4 W 6 ATTORNEYS March 31, 1970 B. E. LONG 3,503,161

METHOD OF TREATING A CONTINUOUSLY CAST BILLET Filed Sept. 29, 1967 3 Sheets-Sheet 3 INVENTOR.

BYRNS E. LONG BY ATTORNEYS United States Paten 3,503,161 METHOD OF TREATING A CONTIYUOUSLY CAST BILLET Byrns E. Long, Williamsville, N.Y., assignor to Cayuga Machine & Fabrication Co., Inc., Depew, N.Y., a

corporation of New York Filed Sept. 29, 1967, Ser. No. 671,722 Int. Cl. B24b 1/00, 7/00 US. Cl. 51-281 Claims ABSTRACT OF THE DISCLOSURE A method and apparatus are provided for grinding off the corner edges of a continuously cast metal billet of generally rectangular shape in cross section while the billet remains attached to the tundish which forms the same.

BACKGROUND OF THE INVENTION It is known to continuously cast a metal billet of generally rectangular shape in cross section by discharging molten metal through the bottom opening in a tundish. The metal which flows from the tundish quickly solidifies externally to provide a relatively stiff outer casing defining the external shape of the billet and surrounding and confining a hotter and still quite plastic core which progressively solidifies as a given portion of the billet moves farther away from the tundish. While the billet remains readily bendable it is turned horizontally and cut into desired lengths.

Apparently because of the weight of the hot billet hanging from the tundish the billet tends to tear and forms cracks at its corner edges. These cracks adversely affect the quality of the billet for subsequent use such as forging, for example. Presently these cracks are removed by grinding otf the corner edges of the individual cut up lengths and thus when the metal is very rigid and consequently hard. This renders grinding difficult and with the added handling of the cut up lengths, the technique as a whole is not fully satisfactory.

SUMMARY OF THE INVENTION The purpose of the present invention is to provide an improved technique for removing the cracks which unavoidably develop along the corner edges of a continuously cast metal billet.

In accordance with the present invention the corner edges of a continuously cast metal billet of generally rectangular shape in cross section are ground off while the billet remains attached to the tundish which forms the same and before being cut up into individual lengths. This has the advantage of grinding off the metal while it is relatively soft and hence easy to abrade. Also, by performing the grinding operation preferably while the hot billet is descending vertically, hanging of its own weight, less handling is required compared to the present technique. Both advantages are achieved by moving the hot billet past grinding stations Whereat the corner edges are chamfered to the desired extent.

Another feature of the present invention is that the grinder assemblies may be arranged in opposed pairs so that diagonally opposite corners of the billet are engaged by the grinding wheels which thereby have a guiding effect upon the billet as it moves. This tends to keep the billet from wandering during its descent.

Still another feature is to arrange a grinder assembly 80 that the force exerted by it against the billet can be varied to control the depth of the chamfer, assuming a constant velocity of movement of the billet past the grinder assembly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary side elevational view of apparatus for continuously casting two steel billets, for example, including grinding apparatus of the present invention associated with each billet for grinding off its corners.

FIG. 2 is a fragmentary horizontal sectional view of the inventive grinding apparatus, taken on line 22 of FIG. 1.

FIG. 3 is an enlarged fragmentary horizontal sectional view thereof, taken on line 33 of FIG. 1.

FIG. 4 is a fragmentary vertical sectional view thereof, taken on line 4-4 of FIG. 3.

FIG. 5 is another fragmentary vertical sectional view thereof, taken on line 5-5 of FIG. 3.

FIG. 6 is a horizontal sectional view thereof, taken on line 66 of FIG. 1.

FIG. 7 is a perspective view, on a reduced scale, of one of the water cooled shrouds for one of the hot steel billets shown in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the numeral 10 represents an upper platform and the numeral 11 another platform at a lower elevation. Above this upper platform 10' is shown the lower end of a ladle, furnace or other container 12 of any suitable and known construction adapted to contain a melt of steel. This container 12 is shown as arranged to supply molten steel to a first tundish 13 and a second similar tundish 14 spaced therefrom. Tundish .13 is adapted to form a steel billet 15 of generally rectangular shape in cross section which moves vertically downwardly through suitable openings (not shown) in platforms 10 and 11. The other tundish 14 is adapted to form a similar steel billet 16 which descends vertically through openings (not shown) in platforms 10 and 11.

Typically, the billets 15 and 16 if square are usually produced in a size ranging from 3 to 6 inches on each side. Billets may be formed with other rectangular shape in cross section. As well, billets of metals other than steel can be employed in the practice of the present invention. Likewise, more or less than two billets may be formed simultaneously.

In accordance with the present invention, each of the hot steel billets 15 and 16 while moving has its corner edges ground off, in order to eliminate the cause of future defects in parts made therefrom as previously noted. Inasmuch as the apparatus for grinding off the corner edges of one steel billet is similar to that employed to grind off the corner edges of the other steel billet, the apparatus associated with right billet 15 will first be discussed. Corresponding parts of the apparatus associated with left billet 16 will be represented by the same reference numerals except as distinguished by the suffix a.

While the frame supporting the grinding apparatus may be of any suitable. construction than shown, and repreresented generally by the numeral 18, is arranged between platforms 10 and 11 and includes four vertical tubular corner members 19, 20, 21 and 22 which stand on lower platform 11 and are suitably anchored thereto. Members 19 and 22 are at the front of the frame and members 20 and 21 are at the rear. An upper horizontal frame mem- 3 ber 23 is arranged between left corner members 19 and 20. Another upper horizontal frame member 24 is arranged between right corner members 21 and 22. Upper horizontal frame members 23 and 24 are arranged at the same level. At a lower level, a horizontal frame member 25 is arranged between front corner members 19 and 22, and a similar horizontal frame member 26 is arranged between rear corner members 20 and 21. These various horizontal frame members are preferably tubular and of square shape in cross section. Suitable gussets slrengthen the connections of the horizontal members to the corner members to rigidity frame 18.

An upper pair of grinder assemblies are suitably supported on right upper horizontal frame member 24, the front one of such assemblies being designated generally by the numeral 28 and the rear assembly by the numeral 29.

Front grinder assembly 28 is shown as including a rigid horizontal support member 30 which extends transversely of frame member 24 and has suitably attached a vertical pivot pin 31 which extends downwardly to be received in a bushing 32 carried by frame member 24. Support member 30 at its left end and on its rear side carries grinder wheel 33 arranged for rotation about a vertical axis and to engage the front corner edge 15f of steel billet 15. Grinding wheel 33 is shown as being fast to a vertical shaft 34 journalled in a bearing 35 suitably secured to support member 30. This support member at its right end and on the front side thereof is shown as having an electric motor 36 suitably secured thereto. This motor 36 is arranged With its drive shaft 38 arranged vertically. The upper end of this shaft 38 has fast thereto a drive pulley 39 and the upper end of shaft 34 has fast thereto a driven pulley 40. A belt 41 passes around pulleys 39 and 40. In this manner energization of motor 36 drives grinding wheel 33. A hood 37 covers approximately the front half of grinding wheel 33 and is suitably secured to support member 30.

The other grinder assembly 29 includes a support member 42 horizontally arranged and pivoted intermediate its ends on right horizontal frame member 24 in a manner similar to that just described for assembly 28. The left end of this support member 42 carries a grinding wheel 43 adapted to engage rear corner edge 15b of billet 15. The opposite end of support member 42 carries an electric motor 44. A pulley and belt assembly represented by the numeral 45 connects wheel 43 drivingly with motor 44. A hood 47 covers approximately the rear half of grinding wheel 43.

Pneumatically operated piston and cylinder means, indicated generally at 46, are operatively arranged between support members 30 and 42 to urge grinding wheels 33 and 43 toward each other. As best shown in FIG. 3, device 46 is arranged to the right of right frame member 24 and comprises a cylinder 48 at one end suitably pivotally connected to support member 42 as indicated at 49. The adjacent end of cylinder 48 has an inlet line 50 and the remote end is shown as having an outlet line 51. A variable pressure regulator 52 of any suitable construction is shown arranged in inlet line 50. Device 46 is also shown as comprising a piston 53 slidably arranged in cylinder 48 and connected to one end of a piston rod 54 the other end of which is suitably connected pivotally to support member 30 as indicated at 55.

Introducing through inlet line 50 a pressurized gaseous fluid such as compressed air and at a pressure controlled by the setting of regulator 52, will cause grinding wheels 33 and 43 to be forced against the front and rear corner edges 15] and 15b, respectively, of steel billet 15.

The left and right corner edges 151 and 15r, respectively, of hot steel billet 15 are ground off by a pair of lower grinder assemblies 58 and 59, as shown in FIG. 6. The grinding wheel 58 of left grinder assembly '58 works on left billet corner 15!; and the grinding wheel 59' of right grind?! assembly 59 Works on right billet corner edge 15r. Grinder assemblies 58 and 59 are shown as pivotally mounted on front lower horizontal frame member 25. The construction of left lower grinder assembly 58 corresponds to upper front grinder assembly 28. The construction of right lower grinder assembly 59 corresponds to that of rear upper grinder assembly 29. As with assemblies 28 and 29, assemblies 58 and 59 are urged so that their grinding wheels 58' and 59' are urged against steel billet 15 by a controllably variable force produced by a pneumatically operated piston and cylinder device such as is indicated at 60 which is similar to device 46 and its associated parts 48-55.

Typically, corner edges 15!, 151', 15 and 15b of billet 15 are ground off or chamfered to a depth of about ,4 or inch. Grinding wheels 33 and 43 may have a starting diameter of about 20 inches and are used until the diameter reduces to about 12 or 13 inches, following which they are replaced. These wheels are compounded of a suitable abrasive material.

In order to protect the grinder assemblies 28, 29, 58 and 59 from the heat given off by hot steel billet 15, this billet is shown as surrounded by a water cooled shroud, represented generally by the numeral 61 in FIG. 7. This shroud includes an upper tubular section, a lower tubular section 63 and an intermediate tubular section 64. As shown in FIG. 1, upper section 62 is arranged above grinding wheels 33 and 43, intermediate section 64 is arranged between these grinding wheels and grinding wheels 58 and 59', and lower section 63 is arranged below lower grinding wheels 58 and 59'.

The water cooled shroud 61 may be of any suitable construction. As shown, it is made up of two formed sheets which provide fiuid passages. A manifold inlet cooling water pipe 65 is shown as servicing the various sections 62-64 through various branch pipes one of which is typically indicated at 66. A manifold pipe 68 conducts water away from sections 6264 after passing therethrough via branch pipes one of which is typically indicated at 69. A gap between shroud sections 62 and 64 as indicated at 70 in FIG. 7 provides access for grinding wheels 33 and 43 to steel billet 15. A similar gap 71 between sections 64 and '63 provides access for grinding wheels 58' and '59. The shroud device 61 thus used above and below each pair of grinding wheels and cooled internally by circulating water, shields the bearings and associated mechanism of the grinder assemblies from the heat of the steel billet 15.

Typically, the continuously cast steel billet 15 feeds past the assembly of grinder assemblies 28, 29, 58 and 59 t the rate of about 10 feet per minute. By varying the pressure of fluid such as compressed air admitted to piston and cylinder devices 46 and 60, the extent of the chamfer cut on the corner edges of billet 15 by the grinding wheels can be varied as desired.

The grinder assemblies associated with left hot steel billet 16 are similar to those described in detail in connection with right billet 15. Thus, a pair of upper grinder assemblies 28a and 29a (FIG. 2), and a similar pair of lower grinder assemblies 58a and 59a (FIG. 6), as well as a shroud device 70a (FIG. 1), are associated with left billet 16. Upper grinder assemblies 28a and 29a are pivotally mounted on left upper horizontal frame member and lower grinder assemblies 58a and 59a are pivotally mounted on rear lower horizontal frame member 26.

From the foregoing, it will be seen that the specific embodiment illustrated and described achieves the stated objectives and advantages. Modifications of the apparatus illustrated may occur to those skilled in the art without departing from the spirit of the invention and accordingly the scope of the invention is to be measured by the appended claims.

What is claimed is:

1. In the method of flowing molten metal through a tundish to continuously cast a billet of generally rectangular shape in cross section which forms with tears and cracks at its four corners, the improvement which comprises removing all four torn and cracked corner portions of said billet while attached to the tundish.

2. The method according to claim 1 wherein said corner portions are ground ofi.

3. The method according to claim 2 wherein the grinding off of said corner portions is performed while said billet is moving.

4. The method according to claim 3 wherein a pair of 10 diagonally opposite corner portions of said billet are ground off substantially simultaneously.

5. The method according to claim 4 wherein said billet is descending vertically.

6 References Cited UNITED STATES PATENTS 2,640,301 6/1953 Hill et a1. 51-40 425,846 4/ 1890 Atha 164-263 359,348 3/1887 Daniels 164-263 2,722,087 11/1955 Hamilton 51-40 X FOREIGN PATENTS 1,335,289 7/1963 France.

JAMES L. JONES, 111., Primary Examiner US. Cl. X.R. 51-80; 164-263

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