TPT September 2012

Technology News

A number of solutions for the revamping of cold rolling mills

mangling diameter. This minimises the rolling axial force that in return affects the quality of the produced tubes, the stability of rolling process, reduction of wear of pinion gears and racks and also provides the possibility of multiple-use of worn-out dies due to their regrinding. The use of ring dies provides the possibility to reduce overall dimensions of the stand, decrease its mass (by 1.5 times) and reduce the loads on the drive mechanism. Roll changing is performed by the assembly rolls and takes not more than one hour. The technical solutions, implemented in the suggested design, allow increased accuracy of rolled tubes; decreased loads on the mill mechanisms to increase their durability; increased die life; reduced roll changing time; increased number of strokes of the stand (due to the decreasing of its mass) when the loads on the drive are the same, and as a consequence increased capacity; and improved work conditions. EZTM JSC has gained experience in using mechanisms with the planetary crank conversion device of the continuous rotation into interrupted (impulse) one. The values of maximum forces in the links of such sizes are 3-4 times less than in some other types of mechanical feed mechanisms. The exact feed and turn of the tube by the new mechanism are provided by firm kinematical connection of the impulse turn of its output links (connected with the transmission of the turn and lead screw) with the continuous rotation drive through the device. Providing the mill with the mechanism with the planetary conversion device allows the implementation of the rolling scheme with the feed and turn in both end positions of the work stand (double feed and turn), which allows it to divide feed and increase the total feed, to increase the mill capacity. The use of feed and turn mechanisms allows increased accuracy and configuration of produced tubes; and increased total feed for double stand stroke due to the usage of the rolling scheme and increased capacity.

dies provided with single-side drive. Due to the stand design, the combination of centre-to-centre distance between work rolls and pinion gear mounted is in accord with the optimal

EZTM JSC has developed a number of solutions for the revamping of cold rolling tube mills of the third model, including the facilitated stand DUO with vertical roll configuration, with the ring

EZTM JSC – Russia Website: www.eztm.ru

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S eptember 2012