Industry
constructions, undergoing significant additional loading. According to the results of industrial usage of rolling bearings 1 (refer to figure 3) in heavily loaded rolling tables 2, (slabbings and thick strip rolling mills, outlet furnace rolling tables, etc) for transport of rolled metal 3, the service life is short, from six to twelve months, depending on their conditions of use.
To increase the durability of these rolling bearing assemblies, a small-sized shock absorber 4 was installed on the base of the outer ring of each rolling bearing 1. They were produced from polyurethane in a form of an undivided ring from 5 to 20 mm thick. The contact surface required quality depended on the total applied radial force (refer to figure 3).
The durability of rolling bearings with small-sized shock absorbers on them on the rolling tables of roughing stands group of PMS 1700 of PJSC ‘ILYICH WORKS’ has increased dramatically from six to twenty four months. Similar shock absorbers on the rolling bearings of conical rolling tables of PMS 3000 provided an increase in bearings durability from four to thirty months. This small change has produced a useful reduction of impact loads on rolling table rolls again showing a significant economic benefit.
In addition, the thickness and width of the polyurethane ring can be adjusted to reduce the radial force two or even three times through better distribution of the forces between steel and polyurethane contact surfaces. It allows the use of rolling bearings of smaller diameter.
3) Installation of a shaft-energy accumulator (refer to figure 4) in the main drive of the rolling stand. This allows the time of metal biting during rolling to be increased two to three times. Its damping coefficient (equal to about 0.3) was established experimentally. Moreover, damping can be significantly increased by the usage of additional friction between polyurethane elastic shaft 2 and cylindrical tube 3 (refer to figure 4, where 1 – half-clutch; 2 – polyurethane elastic shaft; 3 – cylindrical tube; 4 – pin). An experimental shaft, which can provide dynamic rolling torque up to 250 kNm
Figure 3. Simplified view of rolling table
for transport of rolled metal
c a t
a e
t Figure 4. General
view of shaft-energy accumulator
s t
parameters such as stiffness and energy capacity. This means there is a need to absorb additional loads and forces, to reduce their values to safe levels, during operations. The strengths of elastic systems, where additional loads act, depend on stiffness and energy capacity. There are now real industrial examples of commissioning and use of some types of polyurethane shock absorbers. They prove in practice that in many cases it is possible to improve their durability yet avoid increasing the size of parts, using stronger steel grades and more expensive thermal treatments during their production. There is technical evidence here of a new approach where it is clear that components with shock absorbers have better durability than larger components of similar design.
(184,000 lbfft) and an angle of twist of about 180 degrees, will be installed soon in the main drive of rolling stand number 4A of PMS 1700 of PJSC ‘ILYICH WORKS’.
Conclusion Design engineers of steel processing equipment, and staff responsible for its supervision and repair should recognise that the initial load settings on equipment are often incorrect. Additional dynamic loads usually arise in systems that depend on
About the authors Vladlen Mazur MEngMech IEng MIED: Mechanical design engineer at Danieli Heavy Machinery Engineering LLC. Viktor Artyukh: Science graduate in Ukraine (equivalent to the UK PhD), associate professor and head of the Department of Strength of Materials at Priazovskiy State Technical University (PSTU). Gennady Artyukh: Head of the specialist laboratory, ‘Protection of Metallurgical Machines from Breakdowns’ and associate professor of the above mentioned department at PSTU. Maryna Takadzhi: MA, CEO of the Technical Translation Bureau LITERA.
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