TPT March 2012

T echnology N ews Pipe forming mill NAKATAManufacturing Company has developed a completely new forming method that can make quality pipes with lower deformation strain and has higher productivity. The company is a general welded pipe plant supplier covering all equipment from entry section to finishing section. By making full use of a self-developed, high-speed, high-precision FEM simulator, Nakata has developed and brought many unique technologies into the industry, such as the FFX Mill and Roll Box, which apply common-use roll technology and have high formability for quality round and square pipe production. Nearly 50 sets of FFX Mill have been installed during the ten years since its development. Nakata maintains research and development to pursue better quality pipe production. It is realised that there is a limitation in the traditional pipe forming method for a technical breakthrough. Current pipe manufacturing methods can be classified into two basic categories. The first category is roll forming, which is widely used owing to its high productivity and low investment cost for welded tube and pipe production. However, the excessive three- dimensional deformation often gives high forming strain, high work hardening and complicated residual stress to the materials, which is the basic reason for poor product quality. In addition, the limited contact between rolls and materials not only makes the forming unstable due to weak constraint, but also brings high contact pressure, together with the unavoidable slip between the materials and rolls, which lead to bad pipe surface quality and short tool life. These problems are hard to overcome while rolls are used as the main forming tools. The second category is press forming. Nearly plane deformation state over the product’s full length tends to give less strain and better product quality, but it also brings excessive forming load, which limits the product’s maximum length, as well as limiting productivity, and requires very costly press machinery. This method is confined to short length pipe production. Nakata has developed a new pipe forming method named Orbital Die Forming (ODF), aimed at inheriting the advantages from both above traditional methods. In roll forming, it is known that the larger the forming roll’s diameter is, the closer to plane deformation state the forming becomes. However, large rolls with a diameter range from several metres to dozens of metres are required to obtain this kind of ideal deformation mode, which is impossible in reality. Nakata succeeded in getting this kind of nearly ideal deformation state similar to press forming by inventing the ODF method. In this method a multiplicity of die blocks, moving in the circumferential direction on an endless track, are connected together to provide a tool surface with a very large curvature radius and work just like a huge roll. This new forming method has both the high productivity of the roll forming method and the excellent product quality of the press forming method. Those products difficult to produce by roll forming, such as pipes with very thin wall thickness and pipes with difficult- to-form materials, can now be easily made.

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Industry Partner :

Nakata Mfg Co Ltd – Japan Email: sales@nakata-mfg.co.jp Website: www.nakata-mfg.com

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18.08.11 09:50

M arch 2012