Per: Everton Picoli (Gerdau), Thyago Bachim (SKF), Henrique da Rocha Severino (SKF), Renato Nascimento de Castro (SKF), Diego Barbosa Pereira (Gerdau), Diego dos Santos Goulart (Gerdau), Henrique ravanello (gerdau), mateus.rosa@gerdau.com.br (gerdau)
Abstract:
In the steel industry, there are different manufacturing processes for each type of product, one of the equipment responsible for the wire manufacture for the subsequent production of mesh wire and trusses is the Gearbox Stand Mill. This equipment has different passes for the reduction of the diameter raw material (wire rod) until the desired product is obtained. Gearbox Stand Mill LF 02 Pass 1 presented failures in its internal components, such as bearings and gears. In order to understand what problem occurred and determine its root cause, a dynamic analysis of the Gearbox during a manufacturing process with its variables were performed. Thus, the following engineering tools were applied: Vibration Analysis, Operating Deflection Shape – ODS and Numerical Simulation by Finite Element Method - FEM. Vibration and ODS highlighted excitation frequencies, operational modes, which in these frequencies caused relative movements. Results obtained through Vibration analysis and ODS were correlated to numerical simulation, allowing to calibrate FEM model. Also, during simulation, Component Modal Synthesis technique was used, allowing evaluation of the fatigue life internal components (bearing and gear). Based on the field and numerical results obtained in this study, the alignment conditions and geometry of machines with laser system were verified and a structural modification was carried out in the coupling system between gearbox and motor. Technical improvements from this study were applied to eliminate the resonant condition of the system, thus increasing the useful life and reliability of the equipment. The result of this project was failures reduction considering that the average of replacements due to unplanned stops reduced from an average of 10 gearboxes to only 1 in the period of 12-month, thus increasing the MTBF.
