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HEAVY ENGINEERING
This complex loading model shows that if the steel is loaded parallel to the
rolling direction (red arrow in the left model) the fatigue strength will be
higher compared to if it is loaded transverse to the rolling direction (yellow
arrow in the same model)
anisotropic, or directionally dependent, by nature. Inclusions become
deformed or elongate within the steel during the rolling stage, so its fatigue
strength will be higher when loaded parallel to the rolling direction than if it
is loaded transverse to the rolling direction.
This is why Ovako says it makes fatigue testing “frequent and integral
to its process development and benchmarking.” The company uses
ultrasonic testing to develop cleanliness within its own IQ-Steel®, which
stands for ‘isotropic quality’, and also ensures high quality from batch to
batch.
Ovako states: “IQ-Steel has favourable properties in all directions which
can upgrade the performance of components that are subjected to a high
and complex loading. The material can also help to avoid the need for costly
re-melting processes. Ovako identified IQ-Steel as the best solution for
Atlas Copco to be used within its impact system, in which major parts
include the rock drills that are used in the impact piston. The parts are
routinely exposed to high fatigue stress, as shock waves are transferred
through the drill string to the drill bit in order to create the rock drilling
action. With IQ-Steel, stress levels within the impact system can be kept
consistently near the maximum limit of the material. The shock waves
produced remain at such a high level that Atlas Copco can get the best
performance out of their rock drills.”
Per Jonsson, Mechanical Design Engineer for R&D Rock Drills within Atlas
Copco’s Rocktec division, said: “IQ-Steel from Ovako has made it possible
for us to raise the output power of the rock drills due to the increased
fatigue limits resulting from the reduced number of impurities in the IQSteel material. The quality and low impurity content helps us to eliminate
breakdowns and increase the service life of the impact system parts. This has
reduced the running cost.”
Ovako’s expertise as a pioneer in boron steel has also enabled it to
introduce an extensive range of WR-Steel® with dedicated wear resistant
qualities to meet the demands of the mining industry. “Covering a
comprehensive range of hardness levels and hardness intervals,
dimensions, steel grades and a variety of forms, WR-Steel offers
manufacturers an ideal material that is best suited to their production
processes.” Ovako also supplies grinding balls and grinding rods. In order
to maintain the same wear resistance from start to finish with greater
longevity the grinding balls are provided as-rolled or in quenched and
tempered condition for extra hardness. Various steel grades are available
upon request in a range of diameters from 20-70 mm. Ovako grinding rods
come in the as-rolled, straightened condition, ranging in diameter from
75-100 mm and a hardness of 340–400 HBW. IM
Comminuting
your maintenance
expenditure
Köppern roller presses have been proven successful all
over the world in plants for the energy-saving high
pressure comminution of various ores and minerals like
iron ore, copper, gold, molybdenum and diamonds, as
well as cement clinker, limestone and blast furnace slag.
For the comminution of abrasive materials a Köppernpatented wear protection of rollers is available.
Köppern – Quality made in Germany.
•
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State of the art technology
Process technology know-how
High plant availability
Quick roller replacement
Pilot HPGR testing capabilities in Australia, Canada,
Germany and South Africa
For further information please contact
[email protected]
www.koeppern.de
JUNE 2016 | International Mining 85