EZTM JSC develops a number of offers for revamping of cold rolling tube mills of the third model.
For revamping of cold rolling tube mills of the third model the facilitated stand DUO with the vertical rolls configuration with the ring dies provided with the single-side drive has been specially developed.
Due to stand design the combination of center-to-center distance between work rolls and pinion gear mounted is in accord with the optimal mangling diameter. This minimizes the rolling axial force that in return affects well the quality of the produced tubes, the stability of rolling process, reduction of wear of pinion gears and racks and also provides the posibility of multiple-use of worn-out dies due to their regrinding.
The usage of the ring dies provides the possibility to reduce over-all dimensions of the stand, decrease its mass (by 1,5 times) and reduce the loads on the drive mechanism.
The roll changing is performed by the assembly rolls and takes not more than one hour.
The technical solutions, implemented in the suggested design allows to:
- increase the accuracy of the rolled tubes;
- decrease the loads on the mill mechanisms – increase their durability;
- increase the life of the dies;
- the possibility of the multiple-use of the dies due to regrinding over the outer diameter and refacing of the groove;
- reduce the time of roll changing;
- increase the number of strokes of the stand (due to the decreasing of its mass) when the loads on the drive is the same and as a consequence increase the capacity;
- improve the work conditions of the personnel;
- provide the possibility of stimulating of rolling routes.
EZTM JSC has gained a great experience of using the 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 all famous types of mechanical feed mechanisms. The exact feed and turn of the tube by new mecahnism 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 conversion device.
Providing the mill with the mechanism with the planetary conversion device allows to implement the rolling scheme with the feed and turn in both end positions of the work stand (double feed and turn) that allows to divide feed and increase the total feed, that allows to increase the mill capacity.
The usage of feed and turn mechanisms of the supposed design allows to:
- increase the accuracy and configuration of produced tubes;
- increase the total feed for double stand stroke due to the usage of the rolling scheme with the feed in each of the end positions of the stand and as a consequence to increase the capacity.