How to avoid the fatigue life of galvanized steel wire rope? What measures are there?

What are the measures to improve the fatigue life of galvanized steel wire rope? Failure forms such as fracture during use not only bring serious economic losses to users, but also cause major personnel accidents. From the perspective of practical application, the measures to change the fatigue life are as follows:

1. Raw materials and semi-finished products

1) It is required that the steel wire surface shall be free of defects such as scratches, folds, flash and microcracks.

2) The decarburization layer on the surface of wire rod and steel wire is a weak part, and its thickness is generally required not to be greater than 1.5% of the diameter.

3) It is required that after hot rolling and controlled cooling of raw materials (high-speed wire rod), the metallographic structure is mainly sorbite (volume fraction 85%), and the rest is pearlite.

4) The corrosion resistance of galvanized steel wire rope. The commonly used protection method for rope steel wire is galvanizing, and the commonly used method is electroplating.

Galvanized steel wire rope

2. Drawing process

1) When formulating the steel wire drawing process, the dimensional tolerance and ovality of semi-finished steel wire should be carefully selected.

2) Reasonably select the pass compression rate, and adopt the multi pass small compression rate process on the premise of production efficiency.

3) Cooling and lubrication, so as to avoid surface scratch and plastic drop caused by too high temperature rise during drawing.

4) There are requirements for the strength and chemical composition of steel wires in different layers of galvanized steel wire strands. The carbon content of the outer steel wire should be slightly lower than that of the inner steel wire to make it have better toughness, and the manganese content can be slightly higher.

3. Design control

1) Control the paying off tension of each steel wire in the strand and each strand in the rope to make the residual stress distribute reasonably.

2) Try to reduce or control the friction of steel wire and strand when walking in the twisting equipment, so as to control the tension and confirm its surface quality.

3) Correctly design, process and reasonably use the pre deformer, otherwise, the contact pressure between wires will be affected, resulting in changes in stress balance, friction on the surface of wires or strands, and increase the surface defects of galvanized steel wire rope.

4) Pretension. When the pretension is 40% - 50% of the breaking force, it is good for changing its fatigue life, and a good effect can be obtained when the action time is more than 2H.

5) Post treatment. After twisting, forging or compacting the galvanized steel wire rope can change its fatigue life.

4. Correct use

1) Pay attention to the material, hardness, groove shape, size and machining accuracy of the pulley used for the supporting galvanized steel wire rope.

2) Maintain good and correct lubrication.

3) Use within a reasonable temperature range.

4) Pay attention to the influence of environment and medium.