“Intron Plus” JSC (Russia, Moscow):

Sukhorukov V. V., Dr. Eng., Prof., President
Vorontsov A. N., Cand. Eng., Assist. Prof., Leading Specialist of Research Dept., E-mail: avorontsov@intron.ru
Volokhovsky V. Yu., Cand. Eng., Assist. Prof., Leading Specialist of Research Dept.

The problem of safe operation of hot metal hoisting ropes in metallurgical works is investigated. The ropes of traveling cranes are subjected to cyclic tension and high level thermal action whenever the molten metal is being poured from the ladle into a converter. During the periodical ladling the ropes are affected by thermal shocks that gradually change a high carbon wires microstructure which leads to deterioration of their mechanical properties. The structural degradation is accompanied by abrasive wear of the wires. Such heavy duty leads to a great risk regarding the rope bearing capacity. On this point the periodical testing of the ropes technical state in service is of a great importance. The aim of paper is to develop the rope monitoring policy that includes the prior thermocyclic safety criterion, the rope NDT schedule and discard requirements. Several ways are used to attain this purpose: non-destructive examination of rope health after periodical ladlings to reveal the signs of ultimate state coming; tensile breaking tests of individual wires and entire ropes that have been discarded; laboratory and in-situ measurements of temperature field at rope crosssection exposed to thermal shock and theoretical analysis of rope safety factor under combined power-thermocycling loading. Based on the depen dence of rope safety factor and magnetic diagnostic para meter, the rope state feature “allowable-caution-prohibited” is proposed. Two-parameter thermal criterion is used to estimate the rope technical condition under supposed foundry rate and to set the rope tes ting regulations. The presented procedure sets out a practical guide for maintaining the reliability of steel ropes working in hot environments.

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