Production processes

We produce rolls for various areas of industry, for instance: rolls for steel industry, for rubber and plastics industry, work rolls for long products and castings for the tool industry. All our products are manufactured in accordance with the latest guidelines and according to customers’ requirements. Our company is certified in accordance with the international ISO 9001 and ISO 14001 standards. In the foundry there are four melting furnaces with the capacity of 4, 10, 2 x 20 and 30 tons and two horizontal centrifugal machines for casting of rolls with a diameter in range from 550 mm to 1300 mm, body length up to 3500 mm and maximum final machined roll weight of 40 tons. For heat treatment there are 10 gas furnaces available with capacities from 60 to 120 tons and computerized continuous process, which enable us to thermally process a wide spectre of rolls of various dimensions in a short period of time.

In mechanical treatment section there is one grinding machine for rough grinding, 4 grinding machines for final grinding, 12 lathes (Herkules, Waldrich etc.) and 3 milling machines. Besides, there is also other equipment, which allows us to produce rolls according to customers’ requirements and tolerances.

Chemical and mechanical analyses for quality control in the foundry are performed in the suitably equipped laboratory. Quality control department in the mechanical treatment section is equipped with all necessary measurement and other instruments, portable ultrasonic devices and portable hardness testing devices - Equotip. To ensure precise quality control we additionally use 2 ultrasound devices, which are integrated in the grinding machines and Eddy Current technology.

Production Process

Melting melts for working layer, intermediate layer and core.

Melts for working layer and core are prepared. Materials like scrap rolls, steel, pig iron and ferro alloys are used.

Centrifugal Casting

Working layer is horizontally cast into the spinning steel mould. After solidification the mould is placed into a vertical position, then the core is cast. Along the whole casting process, the temperatures of melts are monitored as a function of time in producing an ideal high quality roll.

Cleaning

After cooling of rolls in casting pits, the latter are emptied and the sand is roughly cleaned off. Samples are taken from rolls for the first analysis. The roll is prepared for an ultrasonic inspection.

Interim Control (Metallography, Hardness, FS, US)

Metallographic analysis of the working layer and the core is performed in the laboratory. Moreover, the hardness and FS values are measured.

Heat Treatment

After samples analysis the rolls are stacked in the furnace where they are thermally processed according to regulations, separately for each grade.

Rough Grinding

The rolls are roughly grinded and transported to the mechanical treatment section.

Fine Grinding

In the mechanical treatment section, the rolls are processed by customer’s drawing on 12 lathes of different sizes. Drilling of boreholes and milling of details are the next steps in the production process. Before packaging, the surface of the rolls needs to be grinded.

Final Control

The production process is carefully monitored in all stages. The following measurements are performed on rolls:

  1. Roll geometry
  2. Hardness of the working layer and the necks (bearing surfaces)
  3. Roughness
  4. Pressure testing
  5. Ultrasound testing
  6. Eddy Current testing

NEWS

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