The method of accelerated bench test of rope endurance in accordance with GOST 2387-80 "Steel ropes. Endurance test method" with periodic exposure to a corrosive environment was performed. The main goal of accelerated testing is to obtain information about the endurance of the rope during the test time, less than the specified resource of its operation. The study of steel wire ropes according to the proposed method was carried out on a running machine designed and manufactured at the Technological Park "KhTTs UAI-ROSOIL". The machine provides periodic dipping of the deformable section of the rope in a corrosive environment during reciprocating movement and repeated alternating bending of the sample by 90°. For testing, samples of a steel rope with a diameter of 5.6 mm without coating of two types: according to GOST 14954-80 (I type, with a metal core) and GOST 2688-80 (II type, with a core of organic material) were used. The influence of the lubricant in this work was not considered. The cores, strands, and the rope itself were not coated or saturated with lubricant. The endurance of the steel rope was estimated by the number of bends of the sample until it was completely destroyed. The research results showed that the proposed method allows us to simulate the operation of ropes exposed to river, sea water and various corrosive environments on ships, on drilling rigs, in mines, wells, and also to reduce the test time by more than 3 times. In the statistical processing of the results, it was found that the difference between the true values during the tests according to the proposed accelerated method with respect to the standard method does not exceed 7 %, and the relative measurement error is less than with standard tests.

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The paper presents the results of a comparative analysis of methods for testing the low-temperature properties of rope lubricants. Studies have shown that the designation of the temperature range for the use of the rope must be carried out taking into account the low-temperature properties of the rope lubricant used in its manufacture, determined in accordance with GOST 20458-89. The use for these purposes of the instructions of GOST 11507-78 or EN 12593 : 2007, which are intended for testing the low-temperature properties of bitumen, can lead to a significant unjustified reduction in the service life of the rope, since the test method according to the European standard provides for static loading of the sample film applied to the steel plate during its bending, and according to the Russian state standard, shock loading of the sample is provided, which, according to the authors, is closer to the real operating conditions. It is shown that the maximum effect of increasing the wear resistance of the rope at low temperatures is given by the lubricants having the best low-temperature properties determined by the standard method, which is confirmed by the complete correlation of the comparative results of testing the low-temperature properties and wear resistance of the rope at low temperatures. The authors have experimentally confirmed that the highest wear resistance of the rope at low temperatures is provided by lubricants, which have the best low-temperature properties, determined in accordance with GOST 20458-89. It has been established that lubricants, which have unsatisfactory lowtemperature properties, significantly reduce the service life of ropes that are operated at low temperatures, in some cases even with respect to an unlubricated rope. The authors suggest that at low temperatures the components of the lubricant crystallize, the resulting crystals play the role of abrasive elements contributing to accelerated abrasive wear of the wire surfaces.

The paper compares the results of endurance tests of steel ropes manufactured in accordance with GOST 2688-80, according to the standard method (GOST 2387-80 "Steel ropes. Endurance test method") without exposure to an aggressive environment and the test results according to the developed extended method, taking into account operating conditions in corrosive environments, in particular marine and freshwater environments. It was found that the periodic impact of sea water on the rope many times (from 2.5 to 9.5 times) reduces the wear resistance of the rope, depending on the lubricant used, when compared with tests according to the standard method and proportionally reduces its technical resource. It is shown that the impact of fresh water, as well as sea water, greatly reduces the wear resistance of the rope, but in somewhat smaller limits. On the basis of experimental studies, it has been shown that the compositions of lubricants, which ensured the maximum wear resistance of the rope according to the tests according to the standard method, showed the worst results when tested with the action of sea water. In this regard, it can be stated that the standard technique does not allow accurately predict the durability of ropes under special operating conditions (in sea and fresh water), which can lead to unreasonable, more than 9 times, reduction of the life of the rope. The complex of the studies carried out showed that when testing steel ropes for endurance, as well as when choosing the most effective rope lubricant, one should give preference to the test results according to the method proposed in the work, which takes into account the effect of a corrosive environment.

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