Study On The Fabrication Process And Fatigue Properties Of Steel Wire Rope For Application On The Elevator

In this paper, it is mainly studied on the steel wire of the austenitic heat treatment, phosphating treatment process, drawing process and the steel wire rope of the fatigue properties under different conditions. The microstructure and fracture morphology of the steel wire were observed by the optical microscope and scanning electron microscope(SEM). The influence of different process parameters on the microstructure and mechanical properties of steel wire was analyzed.The optimal preparation process parameters of steel wire rope with excellent comprehensive properties were obtained.Microstructures observation by SEM of the steel wire under different process conditions showed that the pearlite interlamellar spacing decreased with the increasing of austenitizing temperature, the pearlite size became larger with the holding time prolonged. With the increasing of austenitizing temperature, the hardness of the steel wire was increased, it was about 248 Hv at the temperature of 980 oC. The strength increases with the increase of DV value, while the twisting times and elongation decreases with the increase of DV value. Compared to DV value of 55, when the DV value is up to 65, the strength of the wire rope is increased by 1.37%, the twisting number is reduced by 6.67%, and the elongation is reduced by 5.26%.The optimal heat parameters were as following, the austenite temperature of steel wire was 980℃, the quenching temperature in the liquid plumbum was 540℃, and the DV value was 65. Phosphating process parameters were controlled as following, phosphating temperature was 85 ~ 90℃; free acidity in 12 ~ 16; total acidity was 90 ~ 100; acid ratio was 5-10; accelerator promotion point was 0.8 ~ 1.8. Drawing process was carried as dry pull and wet pull, the drawing speed was 5m/s.With fatigue cycles increasing, the average diameter of the steel wire rope was decreased. The fatigue performance of the steel wire rope with higher packing density was better. While the fatigue properties became worse with the thicker hemp rope in the center of the steep wire rope. Compared to the non-galvanized steel wire rope, the weared length, width and depth of the galvanized steel wire were smaller under the same fatigue cycles(60W or 90W). So the steel wire with a galvanization layer has higher fatigue life.The elastic modulus of the steel wire rope was increased with the pretension increasing. When the pretension is at range of 30%-40% broken force, the fatigue properties will be increased. While the pretension is more than 50% broken force, the fatigue properties will be decreased.