Patent Description:
Sectional steel having relatively complicated cross-section, such as a T- or H-shape, or a shape derived from these base shapes, may show an undesired temperature distribution before and during the rolling process. The temperature difference between thinner portions (e.g. the flange ends in some sections) and thicker portions (e.g. at the junction of the web and a flange) may be as high as about <NUM> to <NUM>. These temperature differentials result in non-uniform microstructure within the steel section, non-uniform mechanical properties and, possibly, in unwanted deformations (bending, fissures or cracks) of the steel section.

To address this problem, the so-called selective cooling process has been devised in the <NUM>. In this process, the thicker areas of the section are selectively cooled at the roughing and/or intermediate rolling stage(s) so that finishing rolling is performed when the section is of a uniform and lower temperature (e.g. of about <NUM>). Selective cooling is carried out by directing water jets to the areas to be cooled before and/or after individual rolling passes. The cooling arrangements (spray nozzles mounted on longitudinal guides) are located in dedicated zones adjacent the rolling mill. To cool a workpiece, it has to be moved out of the rolling mill and into the cooling zone, where it remains for the time it is cooled. Then the workpiece undergoes the next rolling pass (in the reverse direction).

The existing selective cooling processes require the workpiece to be completely moved out of the rolling mill for cooling. Furthermore, between two rolling passes, the workpiece has to remain in the cooling zone for a certain waiting time. Due to the additional transit and waiting times, the overall rolling time increases and the productivity of the rolling mill may decrease. Furthermore, the investments for the installation of the cooling zones are relatively important and their maintenance increases the operational costs of the rolling mill.

Chinese patent application <CIT> discloses an inter-stand cooling device for hot-rolled H-section steel comprising a plurality of cooling sections arranged symmetrically on the two sides of a stand of a rolling mill. A similar cooling arrangement and process is disclosed in Chinese patent application <CIT>. These systems have in common that the integration of the cooling equipment between the stands of the rolling mill allows better utilization of the available space. Furthermore, according to <CIT>, the original production pace can be maintained.

While cooling arrangements as disclosed in <CIT> and <CIT> may increase productivity, there is room for improvement, in particular in terms of versatility and ease of maintenance.

<CIT> relates to the manufacturing of steel H-shapes having large ratios of flange thickness to web thickness, or having extremely thin webs. An apparatus including means for force cooling the flanges during hot rolling of the H-shapes is integrated in side guides. The distance between the right and left guides may be adjustable, so that the distance between the coolant spraying nozzles and the flanges of the steel H-shape may be adapted. Since <CIT> utilizes side guides provided with cooling apparatus, no special supports are required and thus no complicated installations on the entry and delivery sides of each rolling mill are needed.

The preamble of claim <NUM> is based on this document.

<CIT> relates to an inter-frame cooling control method for H-beam hot rolling.

<CIT> relates to the cooling of H-shape steel while it undergoes rolling. Forced cooling devices are installed in a row of universal rolling devices.

<CIT> relates to an inline cooling device of a profile steel rolling mill, comprising a rolling mill working roller device, a steel rolling mill centering cooling device and a side guide clamping device.

A first inventive aspect of the invention pertains to a section mill for the rolling of steel sections, comprising (at least) a universal mill stand and an edger mill stand for rolling a workpiece in a plurality of back-and-forth passes into a steel section having a web and one or more flanges. The section mill further comprises a cooling arrangement, mounted to the stand frame of the edger mill stand or the universal mill stand, for cooling the workpiece while it undergoes rolling during one or more of the passes. The cooling arrangement comprises a cooling box having a spray head with spray openings for spraying jets of pressurized cooling liquid (e.g. water) against the workpiece. The cooling arrangement further comprises an actuator configured to move the cooling box relative to the stand frame of the universal mill stand and/or of the edger mill stand for adjusting a distance between the spray openings and the workpiece.

It is a noteworthy advantage of the cooling arrangement that the distance between the spray openings and the workpiece can be easily adjusted. It should be noted that the dimensions of the workpiece may change from pass to pass. In some applications, the optimal distance may, e.g., amount to about <NUM> with a tolerance of ± <NUM>, while the workpiece could be compressed or stretched in width by several centimeters. Accordingly, the possibility of adjusting the distance between the spray head and the workpiece to the optimal value will be highly appreciated.

Another advantage of carrying out the spray cooling in or between the stands of a section mill is that the workpiece is well constrained in lateral position. This is not necessarily the case in a dedicated cooling zone. Accordingly, a comparatively small spraying distance may be achieved thanks to the invention without taking an increased risk that the cooling arrangement is damaged due to a collision with the workpiece.

It will be appreciated that the cooling arrangement may be a selective cooling arrangement in the sense that it is configured for selectively cooling (only) certain portions of the workpiece, e.g. the joint between the web and a flange, an entire flange, areas of locally increased thickness, etc. The cooling boxes of the cooling arrangement are preferably arranged so as to locally cool (only) the specific portions, e.g., the one or more flanges as a whole or where they are joined to the web only.

According to an embodiment of the invention, the actuator may be part of a translation mechanism, e.g., a translation mechanism that constrains the motion of the cooling box to a translation in the plane of the web of the workpiece.

For facilitating maintenance or exchange, the cooling box is preferably fitted releasably to the actuator. Advantageously, the cooling box comprises a quick-lock fitting for connecting the cooling box to a cooling liquid supply and/or one or more quick-lock couplers for releasable locking engagement with the actuator.

For even more flexibility, the spray head may be configured removable. In that case, the spray head could be replaced with another one without the need for replacing the entire cooling box. Spray heads with different configurations (in terms of, e.g., height, length, density of the spray openings, dimensions of the spray openings etc.) could thus be used on the same cooling box. It may be worthwhile noting that the choice of the spray head may be made depending on the steel section to roll.

According to a particularly preferred embodiment of the invention, the cooling box is mounted to the stand frame in lieu of a flange roll, a pusher (e.g. one or more hydraulic cylinders) arranged on the stand frame for pressing the replaced flange roll against the workpiece being used as the actuator and the cooling box being connected to the cooling liquid supply of the replaced flange roll. What is particularly interesting in this embodiment of the invention is the ease of mounting the cooling box. No additional frame is needed for the cooling arrangement and, furthermore, the existing cooling liquid supply of the mill stands can be used. A further advantage lies in the fact that the mechanism for positioning the flange roll provides the degrees of freedom that are sufficient for correctly positioning the cooling box relative to the workpiece.

Typically, in an edger mill stand or a universal mill stand, the rolls are rotatably mounted on so-called roll chocks. The roll chocks are supports that can be moved with the roll mounted therein inter alia to regulate the pressure between the roll and the workpiece. The roll chocks are typically fixed on the stand frame via hydraulic cylinders. These hydraulic cylinders typically comprise loading cylinders, which exert the pressure on the rolls necessary for deforming the workpiece, and one or more balancing cylinders, which maintains the roll chock in contact with the loading cylinders by pulling in the opposite direction.

Preferably the cooling box is mounted to the stand frame in lieu of the roll chock of the flange roll (and of the flange roll itself).

The actuator for moving the cooling box relative to the stand frame may be or comprise a hydraulic actuator (e.g. a hydraulic cylinder), a pneumatic actuator, an electric actuator or, for manual adjustment of the distance, a mechanical actuator. If the cooling box is mounted in lieu of a roll chock, the actuator preferably comprises the loading cylinders of the roll chock.

Preferably, the actuator is remotely controllable from a control center. It will be appreciated that in modern rolling mills, this is already the case for the loading and balancing cylinders of the roll chocks. Accordingly, an embodiment, wherein the cooling box is mounted in lieu of a roll chock is particularly advantageous.

The section mill according to the first aspect of the invention may be configured for the rolling of any steel section having a web and one or more flanges, e.g. a T-, U-, or H-shaped section. Of particular interest may be a section mill configured for the rolling of H-shaped steel sections having a web and two flanges, which comprises at least one cooling arrangement arranged on each side of the section mill so as to locally cool the flanges where they are joined to the web.

A cooling box for a cooling arrangement configured to be mounted to the stand frame of the edger mill stand or the universal mill stand of a section mill as generally described hereinabove preferably comprises.

Preferably, the one or more couplers are quick-lock couplers and/or the fitting is a quick-lock fitting. As used herein, the term "quick-lock" qualifies a fitting or a coupler that locks itself automatically to its counterpart upon engagement.

The coupling elements of the cooling box (e.g. the quick-lock couplers and fitting) are preferably configured for connection with the loading and balancing cylinders and the cooling water supply of a roll chock. The fact that the existing water supply of the replaced roll chock can be used constitutes an interesting advantage, since it is not necessary to install an additional water supply in the rolling mill.

The cooling box may be configured stackable between a lower horizontal roll chock and an upper horizontal roll chock. Stackability can be achieved by configuring (in particular in terms of dimensions and weight carrying capacity) the cooling box like the roll chock that is replaced. In certain rolling mills, the rolls (and the corresponding chocks) of a rolling stand are stacked on a trolley, which is introduced into the stand. The rolls mounted in their chock are then lifted from the trolley and brought into position in the stand. Depending on the type of the mill stand, the trolley remains in the stand or is driven out of the stand. To remove the rolls from the stand, the procedure is carried out in the reverse order. If the cooling box is configured stackable, it can be mounted to the stand frame as easily as a flange roll in its chock. Preferably, the cooling box comprises one or more mounts on its upper side for supporting a horizontal roll chock (i.e. the chock of the upper horizontal roll).

Due to the cooling box being as easily removable from the mill stand as the rolls, there is no loss of time to be expected in comparison to a conventional section mill. Accordingly, there is no increase in down times due to mounting and dismounting the cooling arrangements.

A method of rolling steel sections may comprise.

The cooling arrangement used for the cooling comprises an actuator configured to move the cooling box relative to the stand frame of the universal mill stand and/or of the edger mill stand for adjusting a distance between the spray openings and the workpiece.

The steel section rolling method may further comprise adjusting the distance by activating the actuator. It may be worthwhile noting that the cooling arrangement disclosed herein facilitates adjusting the distance between the cooling box and the workpiece from pass to pass or even during a pass, when necessary.

A further aspect of the invention relates to a method of retrofitting a section mill with a cooling arrangement, the section mill being configured for the rolling of steel sections and comprising a universal mill stand and an edger mill stand for rolling a workpiece in a plurality of back-and-forth passes into a steel section having a web and one or more flanges. The method of retrofitting comprises:.

The accompanying drawings illustrate several aspects of the present invention and, together with the detailed description, serve to explain the principles thereof. In the drawings:.

<FIG> schematically shows a section mill <NUM> rolling steel sections. Section mill <NUM> comprises a universal mill stand <NUM> and an edger mill stand <NUM>. The edger mill stand <NUM> is equipped with cooling arrangements <NUM> for locally cooling the workpiece <NUM> while it is rolled. (Only one of the cooling arrangements is visible in <FIG>, the other one is hidden by the workpiece <NUM>. ) The workpiece <NUM> (beam blank) is rolled into its final shape in a plurality of back-and-forth passes. In the illustrations, the workpiece <NUM> has an H-shaped cross-section with a web and two flanges.

Details of a preferred embodiment of the cooling arrangements are best contemplated with reference to <FIG>. Each cooling arrangement <NUM> comprises a cooling box <NUM> having a spray head <NUM> with spray openings <NUM> for spraying jets of pressurized cooling liquid <NUM> against the workpiece <NUM>. <FIG> illustrates how the cooling box <NUM> is positioned relative to the edger rolls <NUM> of the edger mill stand <NUM>. (The workpiece and details of the edger mill stand are not shown for the sake of clarity. ) The cooling box <NUM> comprises a removable spray head <NUM> extending in the rolling direction of the section mill <NUM>. The spray openings <NUM> are disposed in the spray head <NUM>. In operation, the spray head <NUM> is arranged with the spray openings <NUM> facing the outward-oriented face of one of the flanges of the workpiece <NUM>. The spray head <NUM> lies substantially in the plane of the web of the workpiece <NUM>, so that the jets of the cooling liquid <NUM> are projected against the joint area between the web and the flange (best shown in <FIG>).

The cooling box <NUM> shown in <FIG> is configured for replacing a flange roll <NUM> and its roll chock <NUM> on a mill stand. <FIG> schematically illustrates an edger mill stand <NUM>, wherein one of the flange rolls <NUM> and the corresponding roll chock <NUM> are in place, whereas the others have been replaced by a cooling box <NUM>. <FIG> shows the same edger mill stand, wherein both flange rolls and their roll chocks have been replaced by cooling boxes <NUM>.

As indicated before, it is particularly advantageous to mount the cooling box <NUM> in lieu of a flange roll and the corresponding roll chock because the loading cylinders <NUM> can readily be used for positioning the cooling box <NUM> relative to the stand frame and thus to the workpiece. Furthermore, the cooling liquid supply provided for the cooling of the flange roll can serve to supply the cooling liquid to the cooling box <NUM>.

As best shown in <FIG>, the cooling box <NUM> comprises a support body <NUM>, which is dimensioned so as to fit within the space otherwise occupied by the flange roll <NUM> and its chock <NUM>. The spray head <NUM> with the spray openings <NUM> is mounted on the support body <NUM>. The support body comprises a quick-lock coupling arrangement that is of the same type as that of the roll chock <NUM>. In the illustrated embodiment, the hydraulic actuators comprise a centrally arranged balancing cylinder <NUM>, the piston <NUM> of which terminates in a catch <NUM>, and two laterally arranged loading cylinders <NUM>. The support body <NUM> comprises a central coupler <NUM> for receiving the catch <NUM> and interlocking with it (e.g. by rotation of the catch <NUM> about the piston axis). The balancing cylinder <NUM> exerts a pulling force <NUM> on the support body <NUM>, so as to hold the cooling box <NUM> in place against the loading cylinders <NUM>. The loading cylinders <NUM> push against the support body <NUM> at abutments <NUM>. The loading cylinders <NUM> are controlled in such a way as to maintain the cooling box <NUM> in a certain position relative to the stand frame <NUM> and thus to the workpiece <NUM>. To this end, the loading cylinders <NUM> comprise position sensors measuring the positions of the pistons. A controller (not shown) then regulates the hydraulic pressure of the loading cylinders <NUM> in such a way that their pistons stay at the desired position. The balancing cylinder <NUM> applies a force <NUM> in the direction opposite to that of the forces <NUM> induced by the loading cylinders <NUM>, so as to maintain the cooling box <NUM> permanently in contact with the loading cylinders <NUM>.

The support body <NUM> also comprises a quick-lock fitting <NUM> for connecting the manifold <NUM> of the cooling box with the cooling liquid supply <NUM> of the mill stand via a coolant conduit <NUM>.

The spray head <NUM> is removably attached to the support body <NUM> by means of screws, bolts, clamps, or the like (not shown). The joint between the manifold <NUM> and the coolant conduit <NUM> is made fluid-tight by a face-seal gasket <NUM>.

As shown in <FIG>, the mill stand <NUM> comprises a first and a second cooling arrangement <NUM> of the described type, for locally cooling the first and the second flange of the workpiece, respectively. <FIG> shows a variant of the cooling arrangements of <FIG>, wherein the spray head <NUM> is configured for cooling substantially the entire outward face of the flange of the workpiece <NUM>.

The cooling arrangements <NUM> are particularly useful for retrofitting a rolling mill, as the only necessary additional components are the cooling boxes configured in such a way that they can be mounted on a mill stand in lieu of a roll or of a roll in its chock. It should be noted that although in the preferred embodiment described above the cooling arrangements are mounted on an edger mill stand, they could also be mounted on a universal mill stand. Furthermore, while a solution wherein each cooling box replaces a roll within its chock is certainly preferable, a solution wherein the roll chock remains in place and only the roll is replaced by the cooling box could also be envisaged.

<FIG> illustrates a trolley <NUM> for the replacement of the rolls and chocks of a universal or edger mill. In the illustrated case, cooling boxes <NUM> are stacked in-between the lower <NUM> and upper <NUM> horizontal rolls in their respective chocks 66a, 66b and 68a, 68b, taking the place of the flange rolls and the corresponding chocks. To place the components on the trolley <NUM> into the mill stand, the latter is opened and the trolley <NUM> is introduced into the stand. The rolls mounted in their chocks and the cooling boxes <NUM> are then lifted from the trolley <NUM> and brought into position in the stand. Finally, the trolley <NUM> is driven out of the stand or remains therein. To remove the rolls and the cooling boxes <NUM> from the stand, the trolley is introduced, when necessary, and the procedure is carried out in the reverse order.

The cooling boxes <NUM> are configured stackable with the lower <NUM> and upper <NUM> horizontal rolls in their respective chocks 66a, 66b and 68a, 68b. Specifically, the cooling boxes <NUM> are configured such that their relevant dimensions and the load bearing capacity correspond to those of the flange roll chocks that are replaced. In the illustrated case, the cooling boxes <NUM> comprise mounts <NUM> (see also <FIG>) arranged on their upper sides for supporting the chocks 68a, 68b of the upper horizontal roll <NUM>.

Claim 1:
A section mill for the rolling of steel sections, comprising a universal mill stand and an edger mill stand for rolling a workpiece in a plurality of back-and-forth passes into a steel section having a web and one or more flanges;
a cooling arrangement, for cooling the workpiece while it undergoes rolling during one or more of the passes, the cooling arrangement comprising a cooling box having a spray head with spray openings for spraying jets of pressurized cooling liquid against the workpiece, the cooling arrangement comprising an actuator for adjusting a distance between the spray openings and the workpiece;
characterised in that the cooling arrangement is mounted to the stand frame of the edger mill stand or the universal mill stand and in that the actuator is configured to move the cooling box relative to the stand frame of the universal mill stand and/or of the edger mill stand for adjusting the distance between the spray openings and the workpiece.