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Mechel Develops Breakthrough Wire Production Technology
02/05/2008 - Mechel OAO’s Beloretsk Metallurgical Plant subsidiary successfully develops a unique technology to produce stabilized larger-diameter reinforcing wire for prestressed concrete structures.
Mechel OAO’s Beloretsk Metallurgical Plant subsidiary has successfully developed a unique technology to produce stabilized reinforcing wire for the prestressed concrete structures used in the construction industry.
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Mechanical descaling and surface preparation of wire rod in a drawing line became widely popular in Europe and the U.S. for the processing of low-carbon wire rod with diameters up to 18.0 mm, and high-carbon wire rod in diameters of 5.5 to 6.5 mm.
Wire for prestressed concrete structures, however, could be manufactured only from wire rod subjected to sulfuric or hydrochloric acid pickling followed by phosphatation.
European firms attempted several times to implement mechanical descaling for 9- to 16-mm diameter high-carbon wire rod. However, increased wear of drawing dies and growing breakage during drawing and, especially, during subsequent tempering under tension prevented the establishment of a steady wire drawing process.
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As a result of its approximately RUR97.0 million (approximately US$3.9 million) investment, Mechel says it will able to produce approximately 20 thousand tonnes of this product annually.
European firms attempted several times to implement mechanical descaling for 9- to 16-mm diameter high-carbon wire rod. However, increased wear of drawing dies and growing breakage during drawing and, especially, during subsequent tempering under tension prevented the establishment of a steady wire drawing process.
In developing the technology and equipment that made such processing possible, specialists at KOCH, TRAXIT, and Mechel worked together to solved the following problems:
Larger wire rod diameters require significantly more intense mechanical descaling. The developers determined that a new high performance descaling method was needed to replace local surface quenching the previously applied processes employed to combat this problem.
Special new pre-lubricating salts with high adhesion characteristics were developed, along with modes to apply them and dry them. The previously used borax-based pre-lubricating salts did not provide sufficient adhesion of lubricants for the repeated drawing of a larger-diameter wire.
More intensive wire rod cooling in the Stelmor line was necessary to produce the fine structure needed for larger-diameter wire rod. This process development presumes optimization of the wire rod rolling and cooling modes of rolling mill 150.
These process developments enabled researchers to establish stable drawing of 5.0-mm diameter wire at reasonable drawing speeds, matching the process to phosphate coated stock material. Researchers successfully processed the wire on the stabilizing line supplied by GCR - Eurodraw.
PC wire is used in prestressed concrete applications such as railroad ties, reinforced-concrete pressure pipes, road slabs, etc. In Russia and CIS, tempered high-tensile wire was typically used for that purpose. With the new process, three-to-four-times-lower relaxation (losses of wire tension force) in the final products as well as their 10-to-30% higher strength will enable builders to reduce consumption of reinforcing materials.
"The new technological process enables producing high quality finished products, while complying with environmental and industrial safety requirements and reducing production costs," commented Mechel Management OOO Chief Executive Officer Vladimir Polin. “In addition, the process enables Mechel for the first time in Russia and CIS to implement manufacturing stabilized wire from Stelmor-type wire rod, ensuring high production performance.
The new equipment and technologies enable Mechel to manufacture stabilized reinforcing wire conforming to principal international standards, which have better consumer properties as compared to the GOST standard requirements," concluded Vladimir Polin.
Mechel, one of the leading Russian mining and metals companies, unites producers of coal, iron ore, nickel, steel, rolled products, and hardware. Mechel products are marketed domestically and internationally.
