Manufacturing process and technology

Manufacturing process and technology

Rolls manufacturing process starts with incoming materials test for conformity with the State Standards and Standards of the Factory. Thereafter materials go to the foundry, where furnace feed is prepared according to rolls designation.
Rolls material is melted in induction crucible furnaces (IFM-12, 20 and 30 ton.), produced by ABB Process Industries GmbH (Germany).

Proximate analysis of chemical composition from sample is made by spectral method using automatic analyzer OBLF.

After it is clear that melt characteristics conform to necessary requirements, metal is tapped from induction furnaces.

Rolls casting is operated using a crane scale and at melt temperature corrected based on results of thermo-graphic analysis.

Temperature control of such processes as casting molds painting, mounting and demounting is carried out using a portable infra-red pyrometer.

Machine painting inside casting molds allows to rich high quality of roughing rolls casting surface.

Rolls heat treatment is carried out in furnaces, produced by the Bosio Company (Slovenia) in order to make required microstructure and relieve internal stresses. Conditions of treatment are made subject to rolls materials and dimensions.

Templates from each heat treated roll are cut for further examination in order to:

Control microstructure of rolls shell and roll necks;

Determine hardness and mechanical properties of shell and necks;

Determine size of graphite on various depths of shell.

Thereafter rolls machining starts.

Ultrasonic test takes place in process of machining. It is made in order to reveal latent defects and to control the level of internal stresses.

Rolls machining is carried out in JSC KZPV machine workshop, there are about 80 units of different kinds of machines:

Turning lathes:

Max. Diameter of processing – 1 700 mm.

Max. Length of roll – 8 000 mm.

Max. weight of roll – 63 ton.

Grinding machine (polisher):

Max. Diameter of processing – 1 500 mm.

Max. Length of roll – 8 000 mm.

Max. weight of roll – 40 ton

Milling machine:

Max. Diameter of processing – 1 700 mm.

Max. Length of roll – 8 000 mm.

Max. weight of roll – 40 ton

Boring machine:

Max. Diameter of processing – 1 900 mm.

Max. weight of roll – 50 ton

During machining process rolls are examined by following instrumentation:

-Portable electronic hardometer “Equo Tip-2” (Switzerland) for hardness control on rolls surface and on various depths of rolls shell;

-Certified measurement instrumentation, including micrometers, indicating, slide, depth, limit gages and electronic micrometer devices “MICROMASTER” produced by “TESA” Company (Switzerland) for geometry control;

-Portable electronic device “Surftest SJ-201” produced by the “MITUTOYO” (Japan) for surface roughness control.

Over 2006-2009 period we plan to renovate our machinery by purchasing of 7 numerical control machines:

Portal milling machines;

Turning- milling- grinding machine;

Machining center;

Roll-turning machine;

Rotary-turning lathers with milling and grinding functions.