News

16 Jan 2008

A sizing mill designed and manufactured by EZTM JSC for Sinara tube works was assembled and tested at the end of December 2007.

The mill is intended for tube diameter sizing at a temperature of 500-850ºC and installed in a heat treatment line. Sized tubes parameters are as follows: steel seamless hot-rolled tubes (GOST 8731), casing tubes and tubings (GOST 632, API 5CI and GOST 633) and line pipes (API 5L). Tube diameters are from 50 mm up to 168,3 mm, wall thickness is 5 mm – 25 mm and tube length is from 5 m to 13 m.

The sizing mill consists of four 3-high working stands mounted in a bracket. Rolls are independently driven via gear-type spindles by independent two-stage spur-gear speed reducers and electric motors mounted on special frames around the bracket. The reducers and electrical motors are inclined to each other at an angle of 120 degrees. There are two horizontally inclined reducers and a parallel one in each stand driving line. Reducer input shafts are connected with the electrical motor via the gear-type spindles.

The rectangular working stands with fixed pass are mounted in the bracket with their bearing surfaces for further adjustment and centering. To overlap roll passes every second stand is installed in inverted position (180 degrees). The stands are mounted in such a way to make their output shafts interparallel.  

The stands are slid on their slide rails to a loading table by a stand changing device. In the course of changing process hydraulic devices mounted on the reducers retract toothed holders and the stand is able to slide into the bracket opening.

It is the first time when EZTM JSC designed and manufactured a 3-high mill with individually driven rolls. The distinguishing feature of the mill is an increased load carrying capacity. It is connected with so-called "warm" sizing at a rolling temperature of 500ºC.

Besides computer-aided 3D modeling method and preparation of design documentation in the form of an integrated corporate information system based on ASKON Compas 3d and Lotsman:PLM Russian software programs were used. Computer-aided system allowed to run simultaneously several design processes reducing detailed design execution period. Moreover all design works were performed from scratch due to tight contract terms. And 3D modeling method allows to eliminate layout faults common for manual design.

The mill has successfully passed all acceptance tests and is being shipped to the Customer.

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