Roll stand
In rolling mills , the rolling stock is shaped on a rolling stand . This shape is known as rolling . The rolling takes place between at least two work rolls that are mounted in a roll stand. The structure of a rolling stand depends on the number of rolls, the position of the rolls, the shape of the rolls, the forces acting during rolling and the accuracy requirements of the rolling stock. There are rolling mills with just one as well as those with several rolling stands arranged one after the other or next to one another.
Components of a roll stand
Regardless of the type of roll stand, there are basic machine elements from which roll stands are usually composed. Further elements that can be used on a roll stand are fittings, roll bars, sliding rulers, entries or designs.
Roll stand
A roll stand consists u. a. of two roller stands, either frame or cap stands. While the frame stands have a fixed, closed head, the cap stands are equipped with a detachable head. Both types of stands are attached to so-called base plates. These base plates are attached to the foundation of the roll stand. The stands with their substructure and their head form a so-called window. This window must be larger in height and width than the diameter of the rollers used. The installation with the rollers can be exchanged for reconditioning.
Chocks
The chocks are housed in the windows of the stand construction. In these chocks, the working and, if available, the back-up rollers are stored and guided. The bearings are subject to high requirements, on the one hand to reduce the occurring friction to a minimum and on the other hand to absorb the rolling forces that occur during the work process. Depending on the intended use, plain or roller bearings are used.
Adjusting device
Adjustment devices are used to adjust the roll gap formed between the work rolls. In two-high or four-high stands, the lower work roll is usually fixed and only the upper work roll can be turned on. This adjustment allows the thickness to be rolled to be changed without having to change the chocks with the rolls. The employment can be done hydraulically or mechanically. The adjusted roll gap through the adjustment can be displayed digitally or mechanically. If the rolls are changed in order to influence the roll thickness, we do not speak of adjusting, but of adjusting.
Drives
While steam drives were still used in the development phase of the various rolling processes, rolling stands are currently only equipped with electric drives. Three-phase motors or direct current motors are used depending on the type of scaffolding. The power transmission from the drive to the roller takes place via comb rollers or spindles.
Types of roll stands
The naming of roll stands depends on the number and position of the rolls and the dimensions of the rolls. Roll stands with two, three or four rolls are the most common. So-called multi-roll scaffolds are less common. In this category, the six-roll stands and twenty-roll stands should be mentioned. Other multi-roll stands are the split block, monoblock and 18-high stands.
Duo scaffolding
Duo stands (two-roll stands) have two rolls. The rolling process is called duo rolling . The rolling stock is guided vertically or horizontally between the two work rolls. The direction of rotation of the rollers can be changed in order to carry out several passes on a stand. Duo roll stands are divided into:
- Universal two-roll stand
- Horizontal two-roll stand
- Vertical two-roll stand
- Double two-roll stand
Trio scaffolding
Trio stands (three-roll stands) have three work rolls. This rolling process is known as trio rolling . The work rolls are arranged in parallel one above the other. The rolling stock is fed alternately between the lower and middle rolls and between the middle and upper rolls. The direction of rotation of the rolls is constant during the individual rolling processes.
Quarto scaffolding
Four-high stands (four-roll stands) are equipped with two work rolls and two backup rolls. The rolling process is known as four-high rolling . The rolling stock is guided between the work rolls. The backup rolls support the work rolls and thus limit the deflection of the work rolls. The following applies: the lower the deflection of the work rolls, the more precisely the thickness tolerances of the rolling stock are adhered to over the rolling width.
Three-pane framework
In the area of long products like rod and tube Dreischeibenhaus frameworks are often used as the last scaffolding. The disks are arranged in a Y-shape at angles of 120 ° to one another and, thanks to their increased wrap around the rolled material, achieve higher reductions and better precision than duo stands with incised gauges .
See also
Individual evidence
- ↑ The SKF Rolling Mills website. Retrieved September 16, 2016.
- ↑ a b c d e f Friedhelm Sänger & Harald Walter: What the rolling miller needs to know about his work , 2nd edition, Verlag Stahleisen GmbH, Düsseldorf 1999, ISBN 3-514-00653-9 .
- ↑ a b Roll stands website from MWE - Mill Technologies. Retrieved September 16, 2016.
- ↑ SMS Siemag AG: Multi-roll mill stands. SMS Siemag AG, 2016
- ↑ Roll stands ( Memento of the original of September 18, 2016 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice. Website of Ilsenburger Heavy Plate. Retrieved September 16, 2016.
- ↑ Information on the three-disc block at kocks.de
