CONTINUOUS STEEL SLAB CASTER AND METHODS USING SAME

- NUCOR CORPORATION

A steel slab caster having a mold with movable opposing mold faces, and methods of using the steel slab caster for casting steel slabs. The movable opposing mold faces may be laterally positioned with respect to each other in a predefined configuration. Molten steel may be introduced into the mold of the slab caster. The lateral positions and/or pressures of the opposing mold faces are monitored at two vertically spaced locations on at least one of the movable mold faces of the opposing mold faces as casting proceeds, and data is generated in response to the monitoring. The opposing movable mold faces may be adjusted in response to the generated data.

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Description
BACKGROUND AND SUMMARY OF THE INVENTION

In the continuous slab casting of steel, molten (liquid) steel from a steelmaking ladle is poured indirectly into a casting mold and cast into semi-finished shapes (slabs, blooms, and billets). The semi-finished shape is determined by the casting machine mold which receives the molten steel from a tundish and casts the steel into a steel strand with a molten inner core and an outer surface solidified by cooling as the strand moves downwardly through the mold. The strand is further subjected to secondary cooling upon exiting from the mold until, the entire strand is solidified. The strand is then cut into slabs, blooms, or billets.

In the continuous caster, the molten melt from the tundish usually flows into the mold through a shroud and submerged entry nozzle (SEN), which is connected to the outlet of the tundish. The SEN discharges the molten metal into the mold to a selected depth below the surface (the “meniscus”) of the melt in the mold. The flow of the molten melt from the tundish is gravity fed by the pressure difference between the liquid levels of the tundish and that of the melt in the mold. The melt flow from the tundish may be controlled by a stopper rod which at least partially blocks the exit port to the shroud, or a slide gate that moves across the outlet port of the tundish to the shroud. As the molten metal enters the mold, the steel solidifies at the water cooled mold walls to form a shell, which is continuously withdrawn at the casting speed to produce the steel strand by oscillation of the mold walls.

In such a continuous slab casting process, the flow of the molten steel into the mold can affect the quality of the cast steel. Since the outlets of the SEN are below the liquid level in the mold, turbulence and other transient changes in the molten steel produce oxide inclusions and gas bubbles, and flow velocities may entrain droplets of molten slag in the cast strand. Also, foreign particles trapped at the meniscus can similarly be entrained in the cast strand and generate surface defects and surface cracks. All of these produce defects in the cast strand, and result in rejection of the product and loss of manufacturing efficiency.

The width of the steel strand exiting the mold is determined substantially by the relative separation and taper angle of opposing faces of the mold. The molten steel in the mold tends to shrink (i.e., pull away from the mold faces) due to cooling as it moves from the top of the mold (e.g., adjacent the SEN) to the bottom exit of the mold. The mold faces are tapered to account for the shrinkage, so that the molten steel moving through the mold may maintain contact with the mold faces. However, this has proved difficult with different steel compositions processed through the same continuous slab caster, which cool at different rates, even with moveable mold walls. The result is product defects, mold damage and breakouts.

A method of continuously casting steel slabs is disclosed that is more reliable in maintaining contact between the mold faces and the melt as the strand moves through the casting mold. The method comprises the following steps:

(a) assembling a casting mold for continuous casting of melt slabs with at least one set of laterally movable opposing mold faces;

(b) introducing molten melt into the casting mold having the movable opposing mold faces;

(c) monitoring lateral positions of the opposing mold faces in at least two vertically spaced locations along at least one mold face of the opposing movable mold faces as casting proceeds;

(d) generating data indicating the lateral positions of the opposing mold faces at the vertically spaced locations in response to the monitoring; and

(e) adjusting the opposed movable mold faces in response to the generated data indicating the lateral positions of the opposing mold faces at the vertically spaced locations.

The method of continuously casting steel slabs may further include adjusting the lateral positions of the opposing mold faces in response to the generated data to maintain a distance set point or a taper set point, or both, between the opposing mold faces as casting proceeds. In accordance with an embodiment of the present invention, the adjusting of the lateral position of the opposing mold faces is performed automatically.

The monitoring of the lateral positions of the opposing mold faces may be accomplished at at least two vertically spaced locations along both mold moveable faces as casting proceeds. The adjusting of the lateral positions of the opposing moveable mold faces is performed in response to the generated data to maintain distance set points between corresponding laterally positioned locations on the opposing mold faces, or to maintain a taper set point of each of the opposing mold faces, or both as casting proceeds.

Adjusting of the opposing mold faces may be accomplished, either manually by an operator or automatically, employing hydraulic, pneumatic, electrical, or mechanical drives, in accordance with a desired embodiment of the present invention. The opposing moveable mold faces may be the narrow faces of the mold. Alternatively, or in addition, the opposing moveable mold faces may be the broad faces of the mold.

In any case, the monitoring of the positions of the opposing mold faces may be accomplished using at least one of temposonic transducers, magnetostrictive position sensors, or linear position sensors positioned on the mold wall, or on the drive assembly. As a back up, or in the alternative, the sensors may sense the temperature of the cooling water flowing through the mold adjacent the particular mold face location which decreases as molten metal moves away from the mold face. Such temperature sensing may be used to give a course indication of whether or not the mold faces are properly positioned.

Alternatively or in addition, the sensors may measure the pressures exerted by the molten metal against the mold face, to measure when the surface of the molten metal moves away from the mold face.

A continuous steel slab caster is also disclosed comprising the following elements:

(a) an oscillatable slab caster mold capable of receiving molten steel and having at least one set of opposing movable mold faces;

(b) at least two sensors adjacent at least one face of the opposing moveable mold faces at vertically spaced locations along the mold face, with each sensor capable of monitoring a lateral position of the adjacent mold face and/or the pressure exerted by the molten metal against the adjacent mold face at the locations, and generating corresponding position and/or pressure data as casting proceeds; and

(c) positioning devices capable of adjusting the opposed movable mold faces in response to the generated data from the vertically spaced locations.

The steel slab caster may further comprise a feedback controller and drive assembly. The feed back controller is capable of actuating the drive assembly to automatically adjust the lateral position of the opposing movable mold faces in response to the generated data, to maintain a relative distance set point between the opposing mold faces and/or to maintain a taper set point of each of the opposing mold faces as casting proceeds. In accordance with an embodiment of the present invention, the at least one set of opposing moveable mold faces are the narrow faces of the mold.

The sensors may comprise temposonic transducers, magnetostrictive position sensors, and linear position sensors. As a back up, or in the alternative, the sensors may sense the cooling water temperature circulated through the mold adjacent the particular mold face location, which increases as molten metal move away from the mold face.

Alternatively, the method of continuously casting steel slabs may be comprised of the following steps:

laterally positioning at least one set of movable opposing mold faces of a slab caster mold with respect to each other in a predefined lateral configuration;

introducing molten steel into the slab caster mold having the at least one set of opposing mold faces;

monitoring the lateral positions of the opposing mold faces and/or pressures exerted by the molten steel against the mold faces at at least two vertically spaced locations on each movable mold face of the opposing mold faces as casting proceeds;

generating data in response to the monitoring; and

adjusting the opposed movable mold faces in response to the generated data at the vertically spaced locations.

The method of continuously casting steel slabs may further include automatically adjusting at least one of the lateral positions of the opposing mold faces in response to the generated d ata to maintain the predefined lateral configuration. In accordance with an embodiment of the present invention, the predefined lateral configuration includes a set point relative distance between the opposing mold faces and/or a set point taper angle of each of the opposing mold faces.

The monitoring may be accomplished using temposonic transducers, magnetostrictive position sensors, and/or linear position sensors. The adjusting may be accomplished using hydraulic, pneumatic, electrical, or mechanical drives, and the opposing moveable mold faces may be the narrow faces of the mold.

The method of continuously casting steel slabs further includes directing the molten steel to exit the mold into a support roller assembly such that the molten steel continues to harden into a solid metal strand having a width dimension substantially defined by the distance between the opposing mold faces at the mold exit. The metal strand may be cut across the width dimension to form solid steel slabs of a predetermined length.

These and other advantages and novel features of the present invention, as well as details of illustrated embodiments thereof, will be more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic drawing illustrating a steel slab caster having a caster mold;

FIG. 2 is a schematic diagram of a caster mold feedback system showing the opposing moveable mold faces of the caster mold of FIG. 1, with a drive assembly and a feedback controller in accordance with an embodiment of the present invention;

FIG. 3 is a schematic diagram illustrating one possible interface configuration to a movable mold face, in accordance with an embodiment of the present invention;

FIG. 4 is a flowchart of a first embodiment of a method of continuously casting steel slabs using the steel slab caster elements of FIG. 1 and FIG. 2; and

FIG. 5 is a flowchart of a second embodiment of a method of continuously casting steel slabs using the steel slab caster elements of FIG. 1 and FIG. 2.

DETAILED DESCRIPTION

FIG. 1 is a schematic drawing illustrating a continuous slab caster 100 having a caster mold 130. The steel slab caster 100 includes a ladle 110 to provide molten steel lit to a tundish 120 through a shroud 115. The tundish 120 directs the molten steel 111 to the caster mold 130 through a submerged entry nozzle (SEN) 125 connected to a bottom of the tundish 120. The caster mold 130 includes at least two opposing narrow mold faces 131 and 132 shown in FIG. 2, which are moveable, and broad mold faces 133 and 134 shown in FIG. 1, which may be fixed or moveable.

The two opposing moveable mold faces 131 and 132 are positioned laterally with respect to each other in a tapered configuration and movable at least in a lateral direction. The width 135 of the steel strand 136 leaving the caster mold 130 is substantially determined by the configuration of the caster mold faces 131, 132, 133 and 134 at the mold exit at 135. The mold 130 with two opposing narrow mold faces 131 and 132 and opposing broad mold faces 133 and 134 may form a substantially rectangular configuration, or any other desired configuration for the cast strand 136. The cast strand 136 leaving the caster mold 130 enters a support roller assembly 140 adjacent broad mold faces 133 and 134, which directs the strand 136 toward a cutting point 150 as the strand cools to a solid form. During casting, water (or some other cooling fluid) is circulated through the caster mold 130 to cool and solidify the surfaces of the cast strand 136. Each time the strand 136 is cut at the cutting point 150, a solid slab 160 is formed having a predetermined length 165.

The caster mold 130 may be oscillating to facilitate downward movement of the molten metal through the mold 130. Such oscillating is distinct and separate from the lateral movement of the opposing moveable mold faces 132 and 132 in accordance with an embodiment of the present invention.

FIG. 2 shows two opposing mold faces 131 and 132 of the caster mold 130, in a caster mold feedback system 200, interfacing with a drive assembly 215 and a feedback controller 210. Sensors 220A-220D and drives 230A-230D are positioned, in accordance with an embodiment, at locations 137 and 138 vertically spaced along moveable mold face 131 and locations 139 and 141 vertically along moveable mold face 132, respectively. If the caster mold 130 is rectangular, the two opposing moveable mold faces 131 and 132 may be positioned substantially symmetrically about the center line 240. The opposing moveable mold faces 131 and 132 are tapered at an angle, with first relative lateral distance 250 between two opposing locations 137 and 139 on the mold faces 131 and 132 at the upper half of the mold faces, and a second relative lateral distance 255 between two other opposing locations 138 and 141 on the mold faces 131 and 132 at the lower half of the mold faces. The first distance 250 is greater than the second distance 255. In accordance with an alternative embodiment, the mold faces 131 and 132 are not symmetrically positioned with respect to each other.

The sensors 220A-220B are positioned and connected to the mold face 131 and the sensors 220C-220D are positioned and connected to the mold face 132, so as to detect a lateral change in the position of the moveable mold faces 131 and 132. The drives 230A-230D are connected to the mold faces 131 and 132 to be capable of changing and/maintaining, as desired, the lateral positions of the mold faces at locations 137-141 adjacent the connections of sensors 220A-220D, respectively. The connections of the sensors and drives to the mold faces may be by pivotable connections (e.g., pin and bushing), or any other suitable type, that permits lateral movement of the mold faces, and permits the measuring by sensors 220A-220D and drive capabilities by drives 230A-230D at the vertically spaced locations 137 and 138 on mold face 131 and at the vertically spaced locations 139 and 141 on mold face 132.

The position sensors 220A-220D may be linear sensors to monitor any linear lateral movement of the opposing moveable mold faces 131 and 132 at the vertically spaced locations on each mold face. For example, the position sensors 220A-220D may comprise magnetostrictive position sensors in the form of temposonic transducers. In a magnetostrictive sensor, a current pulse is generated in the head of the device and sent traveling down a sensor tube. Downstream on the tube, a movable magnet having a magnetic field is used to indicate position. The current pulse interacts with the magnetic field and generates a strain pulse which progresses back up the sensor tube where it is detected at the head of the sensors. The time between launching the electronic pulse and receiving the returning strain pulse allows precise measurement of the magnet position. In accordance with an embodiment of the present invention, the position of the magnet accurately correlates to the lateral position of the mold face location. Other types of position sensors 220A-220D may be used as desired in accordance with various other embodiments of the present invention.

The drives 230A-230D may be hydraulic drives with hydraulic cylinders or cans which are driven by the drive assembly 215. Alternatively, the drives 230A-230D may be pneumatic drives such as, for example, pneumatic cylinders which are driven by the drive assembly 215. Mechanical, electrical or other types of drives and drive assemblies are possible as well, in accordance with various other embodiments.

In operation, the position sensors 220A and 220B monitor the lateral position of the mold face 131 at two vertically spaced locations 137 and 138 on the mold face 131. Similarly, the position sensors 220C and 220D monitor the lateral position of the mold face 132 at two vertically spaced locations 139 and 141 on the mold face 132. The mold faces 131 and 132 may tend to move due to pressure exerted on the mold faces 131 and 132 by the molten steel inside the mold 130. The drives 230A-230D may be used to counter such exerted pressure by pushing on the mold faces to maintain a desired lateral configuration of the mold faces (e.g., to maintain the distances 250 and 255 and resultant taper). Similarly, the mold faces 131 and 132 may tend to move if the molten melt pulls away from the mold faces due to cooling and shrinkage. The drives 230A-230D may be used to counter such shrinkage by moving the mold faces to maintain the desired lateral configuration of the mold faces in contact with the surfaces of the cast strand 136.

Alternatively, the sensors 220A-220D may sense the pressure exerted by the cast strand 136 against the moveable mold faces 131 and 132, and selectively actuate the drives 230A-230D to maintain contact between the mold faces and the surfaces of the cast strand 136. In such an alternative embodiment, the sensors 220A-220D are pressure or force sensors such as, for example, strain gauges. In another alternative embodiment, the sensors 220A-220D may be integral parts of the respective drives 230A-230D.

Signals 221A-221D from the position sensors 220A-220D are fed back to the feedback controller 210. The raw data 221A-221D from the position sensors each correlate to the lateral positions of the mold moveable face 131 at locations 137 and 138, and of moveable mold face 132 at locations 139 and 141. The raw data may be analog or digital signals. Within the feedback controller 210, the signals 221A-221D from the position sensors 220A-220D are converted into digital data indicating the positions of the opposing mold faces 131 and 132 at the vertically spaced locations. The controller 210 compares the position data to predetermined position set points stored in the memory of controller 210 and generates drive signals 231A-231D to the drive assembly 215. The drive assembly 215 commands the drives 230A-230D, by the drive connections 232A-232D (e.g., hydraulic or pneumatic drive lines) in response to the drive signals 231A-231D to move the opposing mold faces 131 and 132 such that the opposing mold faces maintain a relative geometry (e.g., distance set points and taper set points) with respect to each other as defined by the given position data stored within the controller 210, tending to maintain the mold faces in contact with the surfaces of the cast strand as it moves through the mold. The drive signals 231A-231D may be analog or digital signals, depending on the nature of the drive assembly 215.

In accordance with an embodiment, the feedback controller 210 includes instrumentation and control hardware and/or software as well as a processor. For example, the feedback controller 210 may be a programmable logic controller (PLC). The controller 210 is programmable such that the desired data may be modified as desired, and such that control parameters and/or algorithms, used to generate the drive signals 231A-231D in response to the signals 221A-221D, may be modified. The drive assembly 215 may be, for example, a hydraulic drive assembly or a pneumatic drive assembly.

As an alternative, gearboxes and RAM motors having resolvers may be used instead of, for example, temposonic sensors and hydraulic or pneumatic drives. As the RAM motor turns, a resolver that is directly connected to the motor shaft sends a signal to the feedback controller. The signal is converted by the feedback controller into generated data for the corresponding location on the narrow face of the mold. However, such an alternative configuration may not be desired since such a configuration may be less accurate due to backlash in the gear boxes and other configuration inaccuracies such as, for example, inaccurate coupling from a gear box to a drive shaft.

FIG. 3 is a schematic diagram illustrating one possible interface configuration 500 to a movable mold face, in accordance with an embodiment of the present invention. Instead of the drives and sensors interfacing directly to a mold face, the drives and sensors may instead interface to a support bracket which holds the mold face. As a result, a mold face may be more easily changed out, when necessary, without having to affect the drive and sensor connections.

The configuration 500 includes a narrow face support bracket 510 and an endwall post 520. The drives 230C and 230D include thrust axles within cylinder cans and connect to the support bracket 510 through the endwall post 520. The drive 230C connects at an upper location on the support bracket 510 and the drive 230D connects at a lower portion on the support bracket 510. The endwall post 520 is fixed and the support bracket 510 is movable via the drives 230C and 230D. The position sensor 220D is also connected to the support bracket 510 through the endwall post 520 at a lower portion of the support bracket 510. The position sensor 220C is shown connecting to an upper portion of the support bracket 510 and is mounted along a top portion of the endwall post 520.

The connections of the sensors 220C and 220D and drives 230C and 230D to the support bracket 510 may be by pivotable connections (e.g., pin and bushing), or any other suitable type, that permits lateral movement of the support bracket, and permits the measuring by the sensors 220C and 220D and drive capabilities by drives 230C and 230D at the vertically spaced locations. A mold face (e.g., mold face 132 not shown in FIG. 3) interfaces to the support bracket 510 and is fixed (i.e., is not movable) with respect to the support bracket 510. When the support bracket 510 is moved by the drives 230C and 230D, the mold face is, therefore, similarly moved. A similar configuration (not shown) may be positioned opposite the configuration 510 to accommodate an opposing mold face (e.g., mold face 131). Such a configuration 500 operates in a similar manner as described previously herein for FIG. 2.

However, in the configuration of FIG. 3, there is an intermediary support bracket 510 to hold the mold face and an endwall post 520 to secure and support the drives and sensors.

FIG. 4 is a flowchart of a first embodiment of a method 300 of continuously casting steel slabs using the steel slab caster elements of FIG. 1 and FIG. 2. In step 310, a casting mold is assembled for continuous casting of melt slabs with at least one set of laterally movable opposing mold faces. In step 320, molten melt is introduced into the casting mold having the movable opposing mold faces. In step 330, the lateral positions of the opposing mold faces are monitored in at least two vertically spaced locations along at least one mold face of the opposing mold faces as casting proceeds. In step 340, data is generated indicating the lateral positions of the opposing mold faces at the vertically spaced locations in response to the monitoring. In step 350, the opposed movable mold faces are adjusted in response to the generated data indicating the positions of the opposing mold faces at the vertically spaced locations.

As an example, the caster mold feedback system 200 positions the mold faces to the desired position before casting begins. When molten steel is first introduced into the mold 130, the mold faces 131 and 132 may initially tend to move outward, away from the desired lateral position, due to the forces exerted by the molten steel on the mold faces. The position sensors 220A-220D immediately sense any initial movement of the mold faces 131 and 132 and the caster mold feedback system 200 automatically reacts to move and maintain the mold faces in position by the drives 230A-230D.

As the molten steel cools and solidifies at the mold faces 131 and 132, due to circulated water cooling, the surfaces of the solidifying molten melt may tend to move away from the mold faces 131 and 132, and cause shrinkage, of the molten metal as thermal energy transfers from the molten steel to the mold faces. Such shrinkage can cause the forces on the mold faces 131 and 132 by the molten melt to change, causing the mold faces to tend to move inward, for example, toward the molten steel. Again, in such a case, any initial change in position of the mold faces will be immediately sensed and the system 200 will automatically react to maintain the desired position of the mold faces 131 and 132 relative to the surfaces of the cast strand 136. The taper of the mold faces 131 and 132 may also act to assist in accounting for the shrinkage of the molten steel, allowing the surfaces of the cast strand 136 to maintain contact with the mold faces as the molten steel moves downward through the mold 130. Note that the sensors 220A-220D and drives 230A-230D allow adjustments to be made independently, if desired, at each location 137, 138, 139 or 141 to maintain contact between the mold faces and the surface of the cast strand, but since the molten melt tend to cool relatively symmetrically, it is generally possible to maintain the desired configuration of the mold faces 131 and 132. Also, during tailout of the cast strand from the mold at the end of a casting run, the mold faces will tend to move inward toward each other. Again, the caster mold feedback system 200 will compensate for such movement of the mold faces during such a tailout condition.

In accordance with an embodiment of the present invention, the range of the position sensors 220A-220D is zero to twelve inches with an accuracy of 0.0001% of full scale (e.g., 0.003 millimeters). Other ranges and accuracies are possible as well, in accordance with various other embodiments.

The method may further include directing the molten steel to exit the mold 130 into a support roller assembly 140 adjacent broad mold faces 133 and 134, such that the cast strand 136 continues to harden into a solid metal strand having a width dimension 135 substantially defined by the exit from the opposing moveable mold faces 131 and 132. Once the cast strand 136 is solidified, the cast strand 136 may be cut across the width dimension to form a solid steel slab 160 having a predetermined length 165.

Therefore, the caster mold feedback system 200 adapts to changes in forces on the mold faces 131 and 132 in real time to maintain the desired configuration of the mold faces. Such an adaptation allows for a stable steel strand to be produced in the steel slab caster 100, resulting in stable steel slabs 160.

FIG. 5 is a flowchart of a second embodiment of a method 400 of continuously casting steel slabs using the steel slab caster elements of FIG. 1 and FIG. 2. In step 410, at least one set of opposing movable mold faces of a slab caster mold are laterally positioned with respect to each other in a desired lateral configuration. In step 420, molten steel is introduced into the slab caster mold having the at least one set of opposing moveable mold faces. In step 430, the lateral positions of the opposing moveable mold faces and/or pressures exerted by the molten steel against the mold faces are monitored at at least two vertically spaced locations on each movable mold face of the opposing mold faces as casting proceeds. In step 440, data is generated in response to the monitoring. In step 450, the opposed movable mold faces are adjusted in response to the generated data at the vertically spaced locations.

The caster mold feedback system 200 is a dynamic system capable of maintaining the positions of at least two opposing moveable mold faces with respect to a set point, e.g., a predefined centerline 240. Furthermore, during a casting process, the desired configuration of the opposing mold faces may be controlled by an operator, such that the distances 250 and 255 are adjusted in order to start and change casting steel strand with new characteristics (e.g., a narrower or wider width). For example, the mold 130 may be configured such that the desired width 135 of the strand 136 can be adjusted between 36 inches and 65 inches. Such flexibility allows quality product to be maintained at all desired widths with narrow or broadface molds. Furthermore, casting can automatically transition from a first set of casting parameters to a second set of casting parameters without having to interrupt the production of the cast strand exiting the mold.

In summary, a steel slab caster, having a mold with movable opposing mold faces, and methods of using the steel slab caster for casting steel slabs are disclosed. A caster mold feedback system allows dynamic control of the positions of the opposing moveable mold faces during the casting process. Such dynamic control of the opposing mold faces allows for better quality control of the steel strand out of the mold and, therefore, an increase in prime tons of steel produced.

While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from its scope. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A method of continuously casting steel slabs comprising the steps of:

assembling a casting mold for continuous casting of melt slabs with at least one set of laterally movable opposing mold faces;
introducing molten melt into the casting mold having said movable opposing mold faces;
monitoring lateral positions of said opposing mold faces in at least two vertically spaced locations along at least one mold face of said opposing movable mold faces as casting proceeds;
generating data indicating the lateral positions of the opposing mold faces at the vertically spaced locations in response to the monitoring; and
adjusting the opposed movable mold faces in response to the generated data indicating the lateral positions of the opposing mold faces at the vertically spaced locations.

2. The method of continuously casting steel slabs as claimed in claim 1 further comprising adjusting said lateral positions of said opposing mold faces in response to said generated data to maintain a distance set point, a taper set point, or both between said opposing mold faces as casting proceeds.

3. The method of continuously casting steel slabs as claimed in claim 2 where the adjusting of said lateral positions of said opposing mold faces is performed automatically or manually.

4. The method of continuously casting steel slabs as claimed in claim 1 where the monitoring of the lateral positions of said opposing mold faces is accomplished for at least two vertically spaced locations along both mold faces of said opposing mold faces as casting proceeds, and further comprising adjusting said lateral positions of said opposing mold faces in response to said generated data to maintain distance set points between corresponding laterally positioned locations on opposing mold faces or to maintain a taper set point of each of said opposing mold faces, or both, as casting proceeds.

5. The method of continuously casting steel slabs as claimed in claim 4 where the adjusting of said lateral positions of said opposing mold faces is performed automatically or manually.

6. The method of continuously casting steel slabs as claimed in claim 1 where said monitoring is accomplished using at least one of temposonic transducers, magnetostrictive position sensors, and linear position sensors.

7. The method of continuously casting steel slabs as claimed in claim 2 where said adjusting is accomplished using at least one of hydraulic drives, pneumatic drives, electrical drives, and mechanical drives.

8. The method of continuously casting steel slabs as claimed in claim 4 where said adjusting is accomplished using at least one of hydraulic drives, pneumatic drives, electrical drives, and mechanical drives.

9. The method of continuously casting steel slabs as claimed in claim 1 where said opposing movable mold faces are narrow faces or broad faces of said mold.

10. The method of continuously casting steel slabs as claimed in claim 1 further comprising directing said molten melt to exit said mold into a support roller assembly, said molten melt continuing to harden into a solid metal strand having a width dimension substantially defined by said opposing mold faces.

11. The method of continuously casting steel slabs as claimed in claim 10 further comprising cutting said solid metal strand across said width dimension to form a solid steel slab having a predetermined length.

12. A continuous steel slab caster comprising:

an oscillatable slab caster mold capable of receiving molten steel and having at least one set of opposing movable mold faces;
at least two sensors adjacent at least one face of said opposing moveable mold faces at vertically spaced locations along the mold face, with each sensor capable of monitoring a lateral position of the adjacent mold face and/or the pressure exerted by the molten metal against the adjacent mold face at the locations, and generating corresponding position and/or pressure data as casting proceeds; and
positioning devices capable of adjusting the opposed movable mold faces in response to the generated data from the vertically spaced locations.

13. The steel slab caster of claim 12 further comprising a feedback controller and drive assembly capable of actuating the positioning devices to automatically adjust said lateral position of said opposing moveable mold faces in response to said data to maintain a relative distance set point between said opposing mold faces or to maintain a taper set point of each of said opposing mold faces, or both, as casting proceeds.

14. The steel slab caster of claim 12 wherein said at least two sensors comprise at least one of temposonic transducers, magnetostrictive position sensors, and linear position sensors.

15. The steel slab caster of claim 12 wherein said positioning devices include hydraulic drives, pneumatic drives, electrical drives, or mechanical drives.

16. The steel slab caster of claim 12 wherein said at least one set of opposing mold faces are narrow faces or broad faces of said mold.

17. A method of continuously casting steel slabs comprising the steps of:

laterally positioning at least one set of movable opposing mold faces of a slab caster mold with respect to each other in a predefined lateral configuration;
introducing molten steel into said slab caster mold having said at least one set of opposing mold faces;
monitoring the lateral positions of said opposing mold faces and/or pressures exerted by the molten steel against the mold faces at at least two vertically spaced locations on each movable mold face of said opposing mold faces as casting proceeds;
generating data in response to said monitoring; and
adjusting the opposed movable mold faces in response to the generated data at the vertically spaced locations.

18. The method of claim 17 further comprising automatically adjusting at least one of said lateral positions of said opposing mold faces in response to said generated data to maintain said predefined lateral configuration.

19. The method of claim 17 where said predefined lateral configuration includes a predefined relative distance set point between said opposing mold faces and a taper angle set point of each of said opposing mold faces.

20. The method of claim 17 where said monitoring is accomplished using at least one of temposonic transducers, magnetostrictive position sensors, and linear position sensors.

21. The method of claim 17 where said adjusting is accomplished using hydraulic drives, pneumatic drives, electrical drives, or mechanical drives.

22. The method of claim 17 where said opposing mold faces are narrow faces or broad faces of said mold.

23. The method of claim 17 further comprising directing said molten steel to exit said mold into a support roller assembly, said molten steel hardening into a solid metal strand having a width dimension substantially defined by a distance between said opposing mold faces at an exit of said mold.

24. The method of claim 23 further comprising cutting said solid metal strand across said width dimension to form a solid steel stab having a predetermined length.

Patent History
Publication number: 20080179036
Type: Application
Filed: Jan 26, 2007
Publication Date: Jul 31, 2008
Applicant: NUCOR CORPORATION (Charlotte, NC)
Inventors: John Carlton ELINBURG (Jonesboro, AR), Jonathon David OTTS (Blytheville, AR), George GURLEY (Kennett, MO), David Walton PARSLEY (Portageville, MO)
Application Number: 11/627,511
Classifications
Current U.S. Class: Including Product Cutting Or Breaking (164/460); Continuous Casting (164/154.5); Adjusting Mold Size (164/491)
International Classification: B22D 11/126 (20060101); B22D 11/06 (20060101); B22D 11/16 (20060101);