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New developments in cold pilger mills

SMS Meer, the Tube and Copper Plants Division of SMS Demag AG, supplies cold pilger mills and drawing machines for the cold reduction of tubes. The latest genera-tion of this mill type with numerous new developments for the sizes KPW 18 to 75 is now the standard in this field. Characteristic features of this machine series are the lateral changing of the die assemblies and the closed-loop controlled individual servo drives for the feed and turn movements of the tube as well as the fully automated, continuous method of operation. These new design concepts were critical factors for the recent placement of orders for several cold pilger mills for tubes of copper and high-strength special alloys.

The new cold pilger mills from SMS Meer operate fully automatically and continuously. They are equipped with a lateral die assembly changing system to shorten and simplify die changing. A major innovation relates to the generation of the intermittent feed-and-turn movement of the rolling stock. New individual servo drives have now replaced the highly complex mechanical indexing gearboxes which were previously used to convert the constant motor speed into intermittent sequences of movements. This new development which SMS Meer has already employed successfully in smaller mills is now being employed also for the larger mills. For this technology, SMS Meer has also developed a new control system which offers greater flexibility with respect to the optimisation of sequences of movements, simpli-fies the mechanical construction and reduces the costs for repairs, maintenance, wear and spare parts, and at the same time opens up completely new possibilities for optimising the product quality. A further feature of the new KPW 50 and KPW 75 cold pilger mills is the crank drive with balancing shaft and rotating weights instead of the vertically oscillating balancing weight previously used. This solution eliminates the need for deep and expensive foundation pits; in addition, the crank drive has a simple and maintenance-friendly design. SMS Meer has already received one order for a pilger mill with this crank drive.

Cold pilger mills for copper tubes

SMS Meer supplies cold pilger mills for a very wide range of applications, from copper tubes through to tubes made from high-strength materials. The new design concepts for the cold reduction process are now employed also for the production of copper tubes in the medium size range. The extruded copper mother tubes are reduced to intermediate sizes on the cold pilger mill and then reduced further to their final sizes in a number of drawing passes. Reduction ratios of more than 90% and high piece weights are important quality features of the cold pilger process for this field of application. The high deformation ratios allow thick-walled extruded mother tubes to be used and improve the eccentricity of the shells. This cost-effective compressive forming process establishes the preconditions for the subsequent drawing processes down to very small final dimensions without heat treatment. The capacity of such cold reducers, depending on type and size, lies between 15,000 and 25,000 t/a. In recent months, SMS Meer has received orders for three cold pilger mills for copper.

Tubes of stainless steel and high-strength materials

The cold pilger process is also employed for smaller tubes of stainless steel and alloys with nickel, titanium and zirconium. These materials are characterised by high strengths and have a limited formability. SMS Meer recently received orders for three pilger mills of the latest generation for these applications designed for tubes with outside diameters from 5 to 26 mm. They operate with a planetary crank drive which emits no inertia forces and permits stroke rates of 320 or 350 strokes per minute in continuous operation.

Further information can be obtained from:

SMS Meer GmbH
- Addr: Ohlerkirchweg 66, D - 41069 Mönchengladbach, Germany
- Tel: (+49/2161) 350 - 0
- Fax: (+49/2161) 350 - 667
- WWW:
- Email.
- Contact: Peter. Byroslawsky

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