In the process of use, failures such as fractures will not only bring serious economic losses to users, but also cause serious casualties. From the perspective of practical application, the measures to improve the fatigue life of galvanized galvanized steel wire rope are:
1. Raw materials and semi -finished products
1) It is required that the surface of the steel wire should not have obvious defects such as scratches, folds, flashes and micro-cracks.
2) The decarburized layer on the surface of the wire rod and steel wire is a very weak part, and its thickness is generally required not to be greater than 1.5% of the diameter.
3) It is required that the metallographic structure of the raw material (high-speed wire rod) is dominated by sorbite (volume fraction 85%) after the completion of hot rolling and controlled cooling, and the rest must be pearlite.
4) In order to ensure the corrosion resistance of galvanized galvanized steel wire rope, the most commonly used protection method of rope making wire is galvanized, and the most commonly used method is electroplating.
2. Drawing process
1) When formulating the drawing process of the steel wire, the dimensional tolerance and ovality of the semi-finished steel wire must be carefully selected.
2) Reasonable selection of the pass compression ratio, and on the premise of meeting the production efficiency, the multi-pass small compression ratio process is adopted.
3) Ensure sufficient cooling and lubrication to prevent surface scratches and excessive temperature rise during drawing, which will cause plasticity to drop.
4) There are certain requirements for the strength and chemical composition of the different layers of steel wire in the galvanized galvanized steel wire rope strand. The carbon content of the outer steel wire should be slightly lower than that of the inner steel wire, so that it has better toughness, and the manganese content can be slightly higher to increase the wear resistance and not easily break.
3. Design control
1) Control the pay-off tension of each wire in the strand and each strand in the rope to make the residual stress reasonably distributed.
2) Minimize or control the friction of steel wires and rope strands when they travel in the twisting equipment, so as to control the tension and ensure the surface quality.
3) Correctly design, process and rationally use the pre-deformer, otherwise, it will affect the contact pressure between the wires, which will cause stress balance changes, and also cause scratches on the surface of the wire or strands, increasing surface defects.
4) Pre-tensioning. When the pretension is 40%-50% of the breaking force, it is better to improve its fatigue life, and the effect time is more than 2h to obtain better results.
5) Post-processing. After the twisting is completed, the galvanized galvanized steel wire rope can be forged or compacted to improve its fatigue life.
4. Correct use
1) Pay attention to the material, hardness, shape and size of the wheel groove and machining accuracy of the pulley used for the galvanized galvanized steel wire rope.
2) Keep it well and properly lubricated.
3) Use within a reasonable temperature range.
4) Pay attention to the influence of environment and medium.
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