Engineering and construction of Edger drive gear reducer for hot rolling mill

The Galbiati Group recently built a large Edger drive gear reducer for a revamp carried out on an existing hot rolling mill at Mariupol, Ukraine.

The engineering process was undertaken by the Galbiati Group in collaboration with Primetals Linz, whilst the Edger drive gear reducer was purchased directly by Metinvest Engineering LLC, Dnipropetrovsk, Ukraine.

Our supply contract covered the design and construction of gear reducers for an Edger drive installed in a hot rolling mill, providing three reduction ratios, with self-supporting vertical twin motor power transmission. Two twin mirror-image reduction gear units, with high-stiffness connecting flange. The Edger drive parallel shaft gear reducer is a vertically mounted unit with two input shafts and two output shafts. The gear trains incorporate shafts, gear wheels and pinions with helical teeth made of 18CrNiMo7-6 steel, hardened, casehardened and ground to meet the standards of DIN grade 6. Low speed shafts made of 42CrMo4 steel.

Edger drive gear reducer for hot rolling mill
Edger drive gear reducer for hot rolling mill

The Edger drive gear reducer is fitted with high quality roller bearings mounted in metal cages ideally suited to the specified speeds of rotation. The twinned mirror-image housings of the two Edger drive gear reducers, machined by way of boring and milling processes, are joined by a high-stiffness connecting flange. The two housings present a structure of electrically welded S355J2 carbon steel. The single housings also have generously sized inspection windows and an air breather, and machined surfaces to facilitate levelling.

Technical data – Edger drive gear reducer:

  • Overall weight = 120 tonnes;
  • Length = 5,534 mm;
  • Height = 5,000 mm;
  • Power = 2 x 1600 kW at 33 rpm;
  • Centre distance = 690 mm.

All machined parts of the Edger drive gearbox are treated with Tectyl to guard against corrosion. The unit is suitably protected and packed in a wooden crate ready for shipment by sea.

Individual components are inspected to determine wear and deformation. Non-destructive tests, are conducted by skilled and experienced technicians, using high-precision instruments and a ZEISS MMZ-G 30 60 25 three dimension measuring machine.

Once completed the Edger drive gearbox, a full-speed running test is performed. Temperatures, noise levels, and vibrations are continuously measured and properly recorded.

A “Certification File” is issued for each drive, which contains the materials and inspection certificates as well as all intermediate and final inspection drive report.