Roller Guide for Wire Rod Block

Design feature of roller guides for wire rod block


The design of roller guides for high speed applications, such as in wire rod mills, requires certain characteristics in order to fulfil the high demands in high speed rolling.

This in respect of precise setting means close tolerance finish of all parts. Much attention has to be paid to the bearing arrangement in order to withstand the extreme high-speed requirements.

Morgårdshammar have two different lines of high-speed roller guides that stand up to these high demands. The since long time well proven 800-series and the new single point adjusted 1000-series type. The 1000-series is available both as two and four roller type.

The two different lines are both well balanced and stand up superb to the required specifications.

The Morgårdshammar roller guides are used today in applications up to 110 m/s continuos rolling finishing speed but are designed for speeds up to 140 m/s.


The design of the Morgårdshammar high speed roller guides where based on the following factors:

Simple design and easy adjustment.
Minimised and standardised components.
Stainless steel material in order to withstand the
severe environment in a WRB
The roller bearings must permit quick acceleration to
very high rolling speeds.
The distance between guide roller and work rolls must be as
short as possible (in cases where no nosepiece is used).
The entry guide halves should be flushed with cooling water
in order to keep them free of scale.





Roller assembly


The roller assembly is specially made for high speed rolling, it has:

Replaceable hardened bushings of tool
steel are pressed into the front part of
the roller holders for shaft location.
The shafts are made of hardened
chrome nickel material. Simple shaft
design is important for low replacement
cost.
The cup springs in the bearing assembly
have a special design to permit proper
prestressing of the bearings.
Prestressing guarantees contact
between balls and bearing races
at all time.
The bearings are provided with ball
cages of fibreglass-reinforced plastic.





Lubrication


When using roller guides in high-speed applications it is a must to use air-oil lubrication. In the Morgårdshammar compact design lubricant is supplied from the guide adapter through the bottom of the guide. However, in such cases where it will not be possible to direct lubrication supply from the bottom, the guides can easily be changed to common supply from hoses via quick release couplings.

The lubricant is supplied via he pivot shaft and further through internal drillings to the bearings.

It is of highest importance that the bearings are shielded on the outside so that an overpressure is obtained inside the bearings to prevent water and residue from penetrating.





Cooling of rollers


In Morgårdshammar high-speed roller guides, as well as in all Morgårdshammar roller guide designs, much care has been taken to sufficiently supply cooling water to the guide rollers. This will increase roller life considerably. In block roller guides the cooling water enters the guide through the bottom from the guide adapter. In cases where it is not possible the guides can easily be changed to common supply from hoses via quick release couplings.

In order to avoid pick-ups on the guide rollers, which can badly mark the rolled stock, cooling water is also flushed through the static entry guides to keep the entire guide channels free of scale and other particles.





Anti-flutter roller guide


In situations where vibrations occur in the stock during rolling the anti-flutter roller guide is a reliable tool to decrease the flutter and increase the stock stability. The higher rolled stock stability leading to a superior product quality.

The anti-flutter guide is mounted in the exit holder on the exit side of the stand and is suitable for both round and oval stock.

The guide is designed with parts common with the entry roller guides, which means minimised inventory.

The Morgårdshammar anti-flutter guides can be provided with or without central adjustment depending on the requirements of the customer. Due to the severe environment inside the block the guide are of stainless steel design.





Optical setting


Precise setting of precise guides calls for precise setting tools. An accurate setting of a block roller guide is crucial. Morgårdshammar have developed and can provide the correct setting tool. There are two optical setting systems available.

The optical setting system, as shown, where the image of the rollers are protected, with magnification, on a template to compare the setting to the theoretical correct groove. The other optical system, the Hi-Line®, uses a camera and computer program instead of the template. The Hi-Line® optical system is a product provided in cooperation with Danieli Automation.

In addition to the optical bench shown above there is also the optical centring projector available. The centring projector with its lamp source is used to center the base plate on the guide mounting system on wire rod block stand. It is also used for setting the roll gap in the roll stand.




In order to avoid misalignment between the setting on the bench and the setting in the roll stand there is a calibrated adjusting piece, which can be seen on the picture on the side before.







Auxiliary equipment

Morgårdshammar can, except for roller guides, also fulfil other needs in our customers wire rod blocks such as:

Guide Mounting systems
Static entry and exit guides
Interstand cooling systems
Lubrication systems