Notes on the selection of steel wire rope used in gantry crane
Wire rope is a flexible component used in gantry cranes, mainly used for lifting machinery. The lifting of the hook group is realized by winding the drum and the pulley group, and the steel wire rope is a directly stressed component in the bridge crane. If the wire rope cannot be used correctly, there will be a big hidden danger.
Wire rope can be divided into five grades according to the strength grade. For lifting goods of the same weight, the higher the strength level, the smaller the diameter of the wire rope. There are two kinds of fillers for wire rope core: hemp core and steel core. Steel cores are generally used in high temperature environments, such as metallurgical cranes. According to the contact form of the steel wire rope, the steel wire rope can be divided into three types: point contact form, line contact form and surface contact form. Each form has its own advantages and disadvantages, which can be selected according to the actual situation. Ordinary bridge and gantry cranes usually use steel wire rope with a strength level of 1670 MPa, hemp core, line contact and smooth surface.
When the load mass increases, the torque or rotation will increase; when the lifting height increases, the tendency of the wire rope to rotate will also increase. In a multi-winding system, the shorter the distance between each wire rope, the greater the tendency to wind each other. The torque or degree of rotation produced by the wire rope will be affected by its structure. Therefore, when choosing a wire rope structure, it is important to decide whether to use "anti-rotation" wire rope or "low-rotation" wire rope, which is usually a multi-strand structure. Under normal circumstances, choose a 6-strand or eight-strand wire rope structure, in addition to the load or the rotation of the multi-winding system may cause difficulty in operation.
The manufacturer of the lifting equipment should determine the minimum strength of the wire rope used in a specific system, be familiar with the local regulations, standards or practical application regulations, and indicate the design factors, use factors or safety factors of the wire rope. In addition, each steel wire rope of a certain length should be sampled for tensile damage test to confirm whether the steel wire rope meets the minimum breaking force listed in its product catalog, and record the actual minimum breaking force on the inspection certificate.
