The Galbiati Group recently built a large pinion stand drive mill drive (Main Drive) as part of 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 Pinion stand mill drive (Main drive) was purchased directly by Metinvest Engineering LLC, Dnipropetrovsk, Ukraine.
Our supply contract covered the engineering and construction of a large Pinion stand mill drive (Main drive) for a hot rolling mill, equipped with 1 x 7000 kW motor. The gears and shafts consist of bi-helical pinions made of 18CrNiMo7-6 steel, hardened, casehardened and ground to meet the standards of quality DIN 3961 Class 6. Gear teeth undergo profile correction to optimize power transmission and contact between mating surfaces of the gear pair. In addition, the girth gear is realized in electro-welded structure in 30CrNiMo8, while the lower shaft is realized in 42CrMo4.
The housing of the Pinion stand mill drive (Main drive) is an electrically welded and stress-relieved structure made of S355J2 carbon steel. It also incorporates generously proportioned inspection windows and an air breather for the levelling of machined surfaces.
The Pinion stand mill drive (Main drive) is fitted with high quality roller bearings mounted in metal cages ideally suited to the specified speeds of rotation.
After sandblasting operation, the housing was painted and treated with epoxy primer, then coated internally with an oil-resistant paint, and externally with a finish colour as illustrated in the photographs below.
Pinion stand drive technical data:
- Overall weight = 63 tonnes;
- Length = 5.800 mm;
- Height = 3.117 mm;
- Power = 7000 kW at 200 rpm;
- Centre distance = 690 mm.
All machined parts of the Pinion stand mill drive (Main drive) 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 of Pinion stand mill drive (Main drive) 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 Pinion stand mill drive (Main drive), 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.
The following pictures and video show the Pinion stand mill drive (Main drive) during test procedures, and fully assembled in the dedicated area of the Galbiati workshops.