TPT July 2007

S traightening & F inishing T echnology

A ccording to the prolific commentator Anonymous, it’s not over till it’s over. Thus last-minute losses are a fact of life. The horse stumbles. The front-runner fades. A defender comes out of nowhere to clear off the line. In tube and pipe production, straightening and finishing operate at that stage. They do not make the product, but they can break it. Suppliers of straightening and finishing technology to tube makers must have a highly cultivated sense of ‘just right’. Too much pressure, tension, torque, speed, angulation,

or force, and material turns to scrap; too little, and the procedure has to be repeated. Now, as ever, time is money. It is also – in an impatient world in which a reputation can be indelibly marked by a late shipment – productivity and profitability. At a certain point in time, a hands-on designer realises that a belt-width smaller than the one in a ‘straight only’ polisher/grinder allows the sanding belt to follow around a curve. The unit, already dual-purpose, gains capability to accept straight, curved, and bent tubes of any ferrous metal. In its next generation it will offer capability for grinding, cleaning, smoothing, and polishing conical, oval, and other complex parts, in many more materials.

This review discloses that kind of progression in straightening and finishing: a steady expansion of the province of ‘the new normal’ from specialists at a make-or-break station in tube production.

straightening machine generation is based on in-depth experience and a continuous exchange with tube mills. Common problems such as hooked ends and tube end deformation are avoided due to the special roll profiles and a combination of hydraulic clamping and cylinder systems. The yield of the mill and the material scrap losses can therefore be efficiently reduced. The high accuracy in straightness is achieved by a special combination of bending and ovalisation of the tubes between the rolls. The tubes are plasticised in a multi-stress combination with a wide contact zone in between the rolls. The hydraulic locking elements of the roll columns are concentric and wear- free, therefore the angular and vertical adjustment of the rolls is precise and repeatable.

Specialised tube straightening machines for heat treatment lines

Reika, Germany, has achieved a great deal of success with its new generation of multi- roll straightening machines. Several machines have been sold to leading German and East European tube mills working in various diameter ranges.

The machines are available for all kinds of seamless and ERW tubes up to 24". The company has also developed special straightening machines for hot tubes being processed in heat treatment lines. In particular, OCTG pipes with high yield strength require this hot straightening operation.

fi Reika’s tube straightening technology for ERW tubes up to 24"

The machines are designed with state-of-the-art 3D CAD systems and offer finite element optimised frames and high rigidity. The straightening machines can be supplied with individual drives for roll wear compensation and dynamic process control. Machines are set automatically with execution of proven mathematical and empirical algorithms, leading to short setup times and repeatable straightness qualities. This new

Reika GmbH & Co KG – Germany Fax : +49 2331 969 036

Email : info@reika.de Website : www.reika.de

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J uly /A ugust 2007