The Study On The Structural Stretch Of Steel Wire Rope And Pre-pull

There exists structural stretch after the steel wire rope is twisted. And the steel wire rope structural stretch brings much inconvenience to users when the rope is being used The production will have to be stopped for users two or three times in the first month during the use of steel in early days wire ropes because the length of steel wire ropes have to be adjusted. That will have a serious affect on the usable performance of ropes, and even the ropes cannot be used. The steel ropes pre-pull not only eliminates the ropes structural stretch, but also improves tension uniformity of strands and wires in rope, and lifts the usable performance, fatigued life and ropes quality.The author makes the research on the steel wire rope structural stretch theory and pre-pull theory from the following aspects.First, the steel wire rope structural theory is presented Starting from the structure of strands and wires in rope and twisting principle, the author sets forth the existent inevitability of the steel wire rope structural stretch and analyses that the structural stretch is permanent stretch and consider the stretch can be eliminatedSecond, controlling the steel wire rope twisting process, using rational and necessary technics methods, controlling the tension uniformity of wires and strands and eliminating the twisting stress not only control the steel wire rope structural stretch, but also are indispensable technics methods for improving the steel wire ropes quality.Third, the biggest contribution in this paper is that the author makes an initial and systematical research on the steel wire rope structural stretch theory and pre-pull method At the first time at home the design idea of pre-pull technics and pre-pull machine is put forward A practical and feasible method is provided for improving the steel wire ropes quality.Last, an analysis and introduction is made for variety of the steel wire rope pre-pull machines. And a concrete pre-pull machine is demonstrated which has good practicability, agile pre-pull technics and excellent affect...