TPT March 2022

AR T I C L E

Fives

Welding box The welding box is equipped with a roll cartridge that houses the lower rolls and the upper compression rolls. When the changeover sequence begins, the top rolls are lowered on the side rolls and the jack’s screws are disconnected from the top roll clevises. Then, the jacks on the operator side tilt over to clear the frontal space for the cartridge to slide out the welding box frame onto the changing carriage. Now the carriage with the incoming roll sets moves and aligns the new roll cartridge in front of the welding box; depending on the configuration, the carriage could be the same one carrying the old roll set or a dedicated one. The process is finally repeated backwards to the working position. Shor test downtime The ETF technology, thanks to the fully automated, crane- free operation, grants a very quick changeover also on heavy mills, down to 1.5 hours from good tube to good tube. Since the operator acts only as a controller, and there’s no need for large cranes, the process can be considered absolutely safe. Additionally, new features with enhanced design permit to accelerate changeover time furthermore. First of all, once the cartridges are on the carriages, they can be lifted as a whole to be transferred into the roll changeover area. Secondly, the first breakdown stand has the option to replace semi-automatically only the upper driven shaft with bearing housings instead of replacing the entire stand when only the upper roll needs to be replaced. The upper jack assemblies slide off the stand to leave space for the upper driven shaft and bearing housings to be lifted and replaced by crane as a whole. Flexible configuration and layout When the available space is an important aspect in the configuration, the ETF solution helps to avoid the need for higher buildings, as the cartridges do not have to be lifted above the mill. At the same time, the carts’ number, configuration and layout can be designed flexibly according to the available space.

Shandong Province Sifang Technical Development Group

Roll cartridges

The cartridges for each section of the mill (breakdown, fin- pass and sizing) are transferred simultaneously to and from the carriage. For each section, a single or double carriage solution can be chosen depending on the stands; the welding box is moved together with the fin-passes. In the single carriage configuration, the same N-slot carriage carries both the empty slots for the roll cartridges to be unloaded and the pre-loaded slots for the groups of cartridges with new rolls to be loaded. Once the roll cartridges have been transferred to the carriage, a simple translation of the carriage aligns the new roll cartridges with the holders for replacement. The carriage moves with the mill. In the double carriage configuration, each carriage has N-slot housings: one empty carriage is dedicated to the cartridges to be unloaded, the other to the ones to be loaded. In this configuration, the movement of the carriages in relation to the mill can follow different paths, depending on the space available and the positioning of the off-line work areas. The carriages can move alongside the mill, orthogonally or even with an angle. Positioning accuracy is a key factor for the fastest possible changeover. Fives’ solution achieves this goal with a FEM- driven designed welded frame that provides the right rigidity; in addition, the carriages are equipped with proximity sensors and inverter driven electric motors that together enable fast, variable and safety-compliant movements. The CE rules are also met by semi-automatic movements that require the operator presence in order to avoid accidents during the carriage translation. The carriages run on rails at floor level, the control boxes are on board and the connection to the power source is made by cable winding, minimising the space required due to the absence of cable carriers. This results in maximum reliability and long maintenance intervals. The ETF system from Fives is an extremely compact roll replacement process, offering an immediate procedure to replace only the first breakdown top roll when necessary. The system features a flexible layout, reliability and precise alignment to make the changeover time as short as possible.

Fives www.fivesgroup.com/steel/tube-mills

ETF, frontal quick change system

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MARCH 2022