EP0087224B1

EP0087224B1 - Continuous casting

Info

Publication number: EP0087224B1
Application number: EP83300443A
Authority: EP
Inventors: Ronald Hinds
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1982-02-01
Filing date: 1983-01-28
Publication date: 1986-09-17
Also published as: ATE22241T1; GB2114928B; GB2114928A; EP0087224A1; JPS58132359A; DE3366163D1; GB8302405D0

Abstract

In the continuous casting of copper bar, the bar B emerging from a casting wheel and traveling to a rolling mill, whilst within its hot working temperature range, passes through a cutting device comprising a pair (1) of cutting wheels (2) positioned on opposite sides of the advancing cast bar and rotatably driven about their axes. Each of the rotatably driven cutting wheels (2) has around its circumference a cutting edge which is urged into continuous engagement with an edge of the advancing cast bar B to cut flash material from the bar. The useful life of the cutting wheels (2) is substantially greater than that of fixedly mounted blades hitherto employed for this purpose.

Description

This invention relates to forming a cast bar according to the first part of claim 1.
It has been found that a metal bar cast using such a casting machine has flash material along the edges of the bar formed at the junction of the edges of the peripheral groove and the endless band and in DE-A-1758179 which forms the first part of the independent claims it has been proposed to cut such flash material from the edges of the cast bar by means of fixedly mounted blades whilst the cast bar, still within its hot working temperature ange, passes continuously from the casting machine to a rolling mill or other hot forming plant. Since the flash material is cut from the edges of the cast bar whilst the cast metal is still within the hot working temperature range of the cast metal, the slight deformations in crystalline grain structure that are produced as a result of removal of the flash material re-crystallize into an unstressed crystalline form so that the stress within the crystalline grain structure of the cast metal is substantially unchanged by removal of the flash material. However, we have found, at least insofar as continuously cast copper bar is concerned, that the working life of the fixedly mounted blades is only a few days and the time involved in replacing worn blades, when the casting process has to be stopped with a resultant loss in bar production, is uneconomic and the replacement operation tedious. Moreover, re-grinding of worn blades, when possible is expensive as the cutting angle of the blade necessary to ensure that only flash material is removed from a cast bar is critical.
It is an object of the present invention to provide an improved process of continuously casting metal bar in which flash material is removed from edges of the bar by an improved cutting device which has a working life substantially greater than that of cutting blades hitherto proposed and used.
According to the invention, the method of forming a cast bar comprises continuously casting molten metal in a casting machine comprising a casting wheel having a peripheral groove and, closing an arcuate length of the groove to form a mould, a continuously moving endless band, and causing the cast bar whilst within its hot working temperature range to travel continuously in the direction of its length from the casting machine to a cutting device which cuts flash material from edges of the advancing cast bar, and from the cutting device to a hot forming plant and is characterized in that the cutting device through which the advancing cast bar passes comprises at least one pair of cutting wheels positioned on opposite sides of the advancing cast bar and rotatably driven about their axes, each of which rotatably driven cutting wheels has around its circumference a cutting edge which is urged into continuous engagement with an edge of the advancing cast bar to cut flash material therefrom.
Since the cutting edge of each cutting wheel extends around the circumference of the wheel and the cutting wheel is rotatably driven whilst it is urged into continuous engagement with an edge of the advancing cast bar, the rate of wear of the cutting edge is substantially reduced as compared with the rate of wear of fixedly mounted blades and it has been found that the working life of a cutting wheel can be many weeks, and in some circumstances several months, before its cutting edge becomes so worn that the wheel has to be replaced whilst its cutting edge is reground or replaced.
The invention also includes apparatus for forming a cast metal bar, which apparatus comprises, in combination, a casting machine comprising a casting wheel having a peripheral groove and, closing an arcuate length of the groove to form a mould, a continuously moving endless band, and, for cutting flash material from edges of a metal bar cast thereby, a cutting device, and is characterised in that the cutting device comprises at least one pair of cutting wheels adapted to be positioned on opposite sides of an advancing cast bar and to be rotatably driven about their axes, each of which rotatably driven cutting wheels has around its circumference a cutting edge, and means for urging the pair of cutting wheels into continuous engagement with edges of an advancing cast metal bar to cut flash material therefrom.
The axis of rotation of each cutting wheel can be so arranged with respect to the axis of the advancing cast bar that the profile of the circumferentially continuous cutting edge of the wheel is simple in form; consequently, re-grinding of the cutting edge of a wheel is a simpler and substantially less expensive operation than re- grinding of the cutting edge of a fixedly mounted cutting blade hitherto used.
Preferably, the axes of rotation of the cutting wheels of the pair extend substantially lengthwise of, and converge in, the direction of travel of the advancing cast bar and, in this case, the axes of rotation of the cutting wheels preferably are each inclined to the direction of travel of the advancing cast bar at an angle of approximately 13°. In its passage between the casting machine and hot forming plant, the advancing cast bar preferably travels in a substantially horizontal plane and the axes of rotation of the cutting wheels of the pair preferably are each inclined to said horizontal plane at an angle of approximately 13°.
Preferably, in its passage between the casting machine and the cutting device the advancing cast bar is continuously engaged by means by which the cast bar is constrained to travel in a substantially rectilinear path to ensure that the cutting wheels remove all and only flash material from the advancing cast bar.
The constraining means preferably comprises a plurality of pairs of freely rotatable roller guides which are in continuous engagement with opposite sides of the advancing cast bar at longitudinally spaced stations and which constrain the advancing cast bar against any substantial transverse movement from said rectilinear path. Preferably, one of each pair of freely rotatable roller guides is fixed in space and constitutes one datum of said rectilinear path of the advancing cast bar and the other of each pair of roller guides is carried by a support which is pivotally mounted about an axis extending substantially parallel to the direction of travel of the advancing cast bar and which has associated means, e.g. a pneumatically or hydraulically powered piston, urging the roller guide carried by the support into continuous engagement with a side of the advancing cast bar.
The constraining means preferably also comprises a plurality of freely rotatable roller guides which are longitudinally spaced along the advancing cast bar and which are in continuous engagement with the upper and lower surfaces of the advancing cast bar to constrain it against substantial upward or downward movement from said rectilinear path. Preferably, the roller guides engaging the undersurface of the advancing cast bar are each fixed in space and constitute a second datum of said rectilinear path of the advancing cast bar and, preferably also, the axis of each of these fixed roller guides lies in the same plane as the axes of a pair of roller guides engaging the sides of the advancing cast bar. Each freely rotatable roller guide engaging the upper surface of the advancing cast bar preferably is positioned between two longitudinally spaced roller guides engaging the undersurface of the advancing cast bar and, preferably also, is pivotally mounted on a support structure about an axis extending transversely of the direction of travel of the advancing cast bar and has associated means, e.g. a pneumatically or hydraulically powered piston, urging the roller guide or guides carried by the support structure into continuous engagement with the upper surface of the advancing cast bar.
Downstream of the cutting device and upstream of the rolling mill or other hot forming plant, preferably the advancing cast bar passes through a chamber in which jets of cleaning liquid are directed on to the upper and lower surfaces and sides of the cast bar.
Preferably, the cutting device comprises two pairs of cutting wheels spaced along the direction of travel of the advancing cast bar, only one of which pairs of cutting wheels is used at any one time and each of which pairs of cutting wheels is independently controlled with respect to the other pair and is mounted on a support structure so pivotally mounted that the pair of cutting wheels can be engaged with or disengaged from the edges of the advancing cast bar as required. By this arrangement, engagement of one pair of cutting wheels and disengagement of the other pair of cutting wheels and disengagement of the other pair of cutting wheels can be readily and rapidly effected and, if desired, whilst the advancing cast bar is passing through the cutting device, thereby eliminating the necessity to stop the continuous casting process.
Where the cutting device comprises two pairs of cutting wheels longitudinally spaced apart, preferably means for constraining the advancing cast bar to travel in said rectilinear path is also provided between the two pairs of cutting wheels. This constraining means preferably comprises a pair of freely rotatable roller guides which continuously engage the sides of the advancing cast bar and which are of substantially the same construction as the pairs of freely rotatable roller guides continuously engaging the sides of the advancing cast bar upstream of the cutting device, and a pair of freely rotatable roller guides which continuously engage the upper and lower surfaces of the advancing cast bar and whose axes lie in the same plane as the axes of the pair of roller guides engaging the sides of the advancing cast bar, the roller guide engaging the undersurface of the cast bar being fixed in space and constituting said second datum for said rectilinear path of the advancing cast bar and the roller guide engaging the upper surface of the advancing cast bar being pivotally mounted on a support structure about an axis extending transversely of the direction of travel of the advancing cast bar and having associated means urging the roller guide carried by the support structure into continuous engagement with the upper surface of the advancing cast bar.
To provide for continuous and automatic control of the depth of cut of the rotatably driven cutting wheels, preferably the or each pair of cutting wheels is urged into continuous engagement with the advancing cast bar by a pneumatically or hydraulically powered piston which can be automatically adjusted as required. Each cutting wheel of the pair may be initially adjusted to accommodate any change in its diameter arising from regrinding of its cutting edge. Preferably, the roller guide engaging the upper surface of the advancing cast bar between the two pairs of cutting wheels serves as a sensor controlling means which automatically adjusts the depth of cut of the cutting wheels having regard to the movement of the sensor.
Preferably, the rotatably driven cutting wheels in continuous engagement with the advancing cast bar and all of the roller guides are each continuously cooled by cooling fluid.
The invention also includes apparatus for forming a cast metal bar by the improved method hereinbefore described.
The improved method and apparatus of the present invention enable metal bar to be continuously cast more economically than methods and apparatus hitherto proposed and employed because the cutting wheels can be accurately set and hence the amount of waste metal can be closely controlled.
The invention is further illustrated by the description of an embodiment of the invention, with reference to the accompanying drawings, in which:-

Figure 1 is a side elevation illustrating the cutting device, roller guides and cleaning chamber;
Figure 2 is a transverse cross-sectional view taken on the line II-11 in Figure 1, drawn on a larger scale, and
Figure 3 is a transverse cross-sectional view of the cleaning chamber shown in Figure 1.

Referring to the drawings, a copper bar B continuously cast by a casting machine comprising a casting wheel having a peripheral groove and, closing an arcuate length of the groove to form a mould, a continuously moving endless band, on emerging from the casting machine and whilst within its hot working temperature range is caused to travel in a substantially horizontal plane and in a substantially rectilinear direction successively through the cutting device shown in Figures 1 and 2, through the cleaning chamber shown in Figures 1 and 3 and then to hot forming apparatus (not shown) where the cast bar is formed into copper rod.
The cutting device shown in Figures 1 and 2 comprises two pairs 1 of cutting wheels 2 spaced along the direction of travel of the advancing cast bar B. Each pair 1 of cutting wheels 2 is mounted on a support structure 3 so pivotally mounted about an axis 4 that the pair of cutting wheels can be engaged with or disengaged from the upper edges of the advancing cast bar B as required, at any one time only one pair of cutting wheels being in engagement with the advancing cast bar. Each cutting wheel 2 of each pair 1 has a circumferentially continuous cutting edge and is rotatably driven about its axis through appropriate gearing by a drive motor 5. The cutting wheels 2 of each pair 1, when in engagement with the advancing cast bar B, are urged into continuous engagement with the cast bar by an adjustable pneumatically powered piston 6. When a pair 1 of cutting wheels 2 is in engagement with the advancing cast bar B, the axes of rotation of the cutting wheels are each inclined to the direction of travel of the advancing cast bar at an angle of 13° and are each inclined to a horizontal plane at an angle of 13°. Each cutting wheel 2 is continuously cooled by cooling fluid which is directed through holes 8 in the wheel on to its cutting edge and which is collected in an underlying reservoir 7 from which it is recirculated in a manner generally known.
The advancing cast bar B is constrained to travel in the substantially rectilinear path to ensure that the cutting wheels 2 remove all and only flash material from the upper edges of the cast bar by constraining means comprising four pairs 11, 12, 13 and 14 of freely rotatable roller guides 15, 16 which are in continuous engagement with opposite sides of the advancing cast bar at longitudinally spaced stations and which constrain the bar against any substantial transverse movement from the rectilinear path, and freely rotatable roller guides 32, 33, 34 and 35 which are longitudinally spaced along the advancing cast bar and which are in continuous engagement with the upper and lower surfaces of the cast bar to constrain it against any substantial upward and downward movement from the rectilinear path.
One roller guide 15 of each pair 11, 12, 13 and 14 of freely rotatable roller guides is fixed in space and constitutes one datum of the rectilinear path of the advancing cast bar B and the other roller guide 16 of each pair is carried by a support 17 which is pivotally mounted about an axis 18 and which has an associated independently adjustable pneumatically powered piston 19 urging the roller guide carried by the support into continuous engagement with a side of the advancing bar. The pair 14 of freely rotatable rollers 15, 16 is at a station intermediate the two pairs 1 of cutting wheels 2.
As will be seen on referring to Figure 1, the freely rotatable roller guides 32 continuously engage the upper surface of the advancing cast bar B and the freely rotatable roller guides 33 continuously engage the undersurface of the cast bar. The axis of rotation of each of the freely rotatable roller guides 33 lies in the same plane as the axes of rotation of one of the pairs 11, 12 and 13 of freely rotatable guides 15, 16. Each roller guide 33 is fixed in space and constitutes a second datum of the rectilinear path of the advancing cast bar B. Each freely rotatable roller guide 32 is positioned between two longitudinally spaced roller guides 33, is pivotally mounted on a support structure 36 about an axis 37 extending transversely of the direction of travel of the advancing cast bar B, and has an associated independently adjustable - pneumatically powered piston (not shown) urging the roller guides 32 carried by the support structure into continuous engagement with the upper surface of the advancing cast bar. The freely rotatable roller guide 34 engaging the upper surface of the advancing cast bar B and the freely rotatable roller guide 35 engaging the undersurface of the advancing cast bar are arranged with their axes of rotation lying in the same plane as the axes of rotation of the freely rotatable roller guides 15, 16 of the pair 14. The roller guide 35 is fixed in space and constitutes a second datum for the rectilinear path of the advancing cast bar and the roller guide 34 is pivotally mounted on a support 39 about an axis 40 extending transversely of the direction of travel of the advancing cast bar and has an associated independently adjustable pneumatically powered piston (not shown) urging the roller guide into continuous engagement with the upper surface of the advancing bar, the roller guide 34 serving as a sensor controlling means which automatically adjusts the pneumatically powered piston 6 urging the cutting wheels 2 into engagement with the advancing cast bar B to regulate the depth of cut of the cutting wheels.
Each of the roller guides is continuously cooled by cooling fluid which is collected in the reservoir 7 and is recirculated.
Downstream of the cutting device, the advancing cast bar B passes through a cleaning chamber 41. As will be seen on referring to Figure 3, within the cleaning chamber 41, cleaning fluid is directed on to each of the four surfaces of the advancing cast bar B from nozzles 42, the cleaning fluid being collected in an underlying reservoir 43 and recirculated in a manner generally known.
The apparatus shown in the drawings enables flash material to be cut from an advancing cast copper bar accurately with negligible or no unnecessary waste of copper.

Claims

1. A method of forming a cast bar which comprises continuously casting molten metal in a casting machine comprising a casting wheel having a peripheral groove and, closing an arcuate length of the groove to form a mould, a continuously moving endless band, and causing the cast bar whilst within its hot working temperature range to travel continuously in the direction of its length from the casting machine to a cutting device which cuts flash material from edges of the advancing cast bar, and from the cutting device to a hot forming plant, characterised in that that the cutting device through which the advancing cast bar passes comprises at least one pair (1) of cutting wheels (2) positioned on opposite sides of the advancing cast bar (B) and rotatably driven about their axes, each of which rotatably driven cutting wheels has around its circumference a cutting edge which is urged into continuous engagement with an edge of the advancing cast bar to cut flash material therefrom.

2. A method as claimed in Claim 1, characterised in that, in its passage between the casting machine and hot forming plant, the advancing cast bar (B) travels in substantially horizontal plane and the axes of rotation of the cutting wheels (2) of the pair extend substantially lengthwise of, and converge in, the direction of travel of the cast bar and are each inclined to said horizontal plane at an acute angle.

3. Apparatus for forming a cast metal bar, which apparatus comprises, in combination, a casting machine comprising a casting wheel having a peripheral groove and, closing an arcuate length of the groove to form a mould, a continuously moving endless band, and, for cutting flash material from edges of a metal bar cast thereby, a cutting device, characterised in that the cutting device comprises at least one pair (1) of cutting wheels (2) adapted to be positioned on opposite sides of an advancing cast bar (B) and to be rotatably driven about their axes, each of which rotatably driven cutting wheels has around its circumference a cutting edge, and means (6) for urging the pair of cutting wheels into continuous engagement with edges of an advancing cast metal bar to cut flash material therefrom.

4. Apparatus as claimed in Claim 3, characterised in that the means for urging the cutting wheels (2) into continuous engagement with an advancing cast bar (B) comprises an adjustable pneumatically or hydraulically powered piston (6).

5. Apparatus as claimed in Claim 3 or 4, characterised in that, there is positioned between the casting machine and the cutting device, means adapted continuously to engage an advancing cast bar (B) travelling in a substantially horizontal plane to constrain the cast bar to travel in a substantially rectilinear path.

6. Apparatus as claimed in Claim 5, characterised in that the constraining means comprises a plurality of pairs (11, 12, 13, 14) of freely rotatable roller guides which are adapted to be in continuous engagement with opposite sides of an advancing cast bar (B) at longitudinally spaced stations and which constrain the advancing cast bar against any substantial transverse movement from said rectilinear path, one roller guide (15) of each pair of freely rotatable roller guides being fixed in space and constituting one datum of said rectilinear path of an advancing cast bar and the other roller guide (16) being carried by a support (17) which is pivotally mounted about an axis (18) extending substantially parallel to the direction of travel of the advancing cast bar and which has associated means (19) for urging the roller guide carried by the support into continuous engagement with a side of an advancing cast bar.

7. Apparatus as claimed in Claim 5 or 6, characterised in that the constraining means comprises a plurality of freely rotatable roller guides (32, 33, 34, 35) which are longitudinally spaced along the route of an advancing cast bar (B) and which are adapted to be in continuous engagement with the upper and lower surfaces of the advancing cast bar to constrain it against substantial upward or downward movement from said rectilinear path, the roller guides (33, 35) adapted to engage the undersurface of an advancing cast bar each being fixed in space and constituting a datum of said rectilinear path of the advancing cast bar and each freely rotatable roller guide (32, 34) adapted to engage the upper surface of an advancing cast bar being pivotally mounted on a support structure (36, 39) about an axis (37, 40) extending transversely of the direction of travel of an advancing cast bar and having associated means adapted to urge the roller guide or guides carried by the support structure into continuous engagement with the upper surface of an advancing cast bar.

8. Apparatus as claimed in Claim 6 or 7, characterised in that the means for urging each pivotally mounted roller guide into continuous engagement with an advancing cast bar (B) comprises an adjustable pneumatically or hydraulically powered piston.

9. Apparatus as claimed in Claim 8, characterised in that, the roller guide (34) adapted to engage the upper surface of an advancing cast bar (B) serves as a sensor which controls means for automatically adjusting the depth of cut of the cutting wheels (2) having regard to the movement of the sensor.

10. Apparatus as claimed in any one of Claims 3 to 9, characterised in that the cutting device comprises two pairs (1) of cutting wheels (2) spaced along the direction of travel of an advancing cast bar (B), only one of which pairs of cutting wheels is used at any one time, and each of which pairs of cutting wheels is independently controlled with respect to the other pair and is mounted on a support structure (3) so pivotally mounted that the pair of cutting wheels can be engaged with or disengaged from the edges of an advancing cast bar as required.