Steel strand-reinforcing seven-wire rope

Steel strand-reinforcing seven-wire rope

Steel strand is a steel product consisting of multiple steel wires twisted together. The surface of carbon steel can be coated with galvanized layer, zinc-aluminum alloy layer, aluminum clad layer, copper plating layer, epoxy coated layer, etc. as needed.
Material: steel
Structure: composed of multiple steel wires twisted together
Classification: prestressed, unbonded, galvanized steel strand, etc.
Production process classification: single wire manufacturing and stranded wire manufacturing
Application: load-bearing cable, tension wire, reinforcing core, ground wire

(1) Classification by use
Prestressed steel strand, (electrical) galvanized steel strand and stainless steel strand. Prestressed steel strand coated with anti-corrosion grease or paraffin and then wrapped with HDPE is called unbonded prestressed steel strand. Prestressed steel strand is also made of galvanized or galvanized aluminum alloy steel wire.
(2) Classification by material properties
Steel strand, aluminum clad steel strand and stainless steel strand. (3) Classification by structure
Prestressed steel strands can be divided into 7-wire, 2-wire, 3-wire and 19-wire structures according to the number of steel wires, and the most commonly used is the 7-wire structure.
Galvanized steel strands and aluminum-clad steel strands for power use are also divided into 2, 3, 7, 19, 37 and other structures according to the number of steel wires, and the most commonly used is the 7-wire structure.
(4) Classification by surface coating
It can be divided into (smooth) steel strands, galvanized steel strands, epoxy-coated steel strands, aluminum-clad steel strands, copper-coated steel strands, plastic-coated steel strands, etc.
The manufacturing process is divided into single-wire manufacturing and stranded wire manufacturing. When making single-wires, (cold) wire drawing technology is used. Depending on the different materials of the product, it can be high-carbon steel wire rods, stainless steel wire rods or medium-low carbon steel wire rods. If galvanizing is required, electroplating or hot-dip treatment should be performed on the single wire. In the manufacturing process of stranded wire, a stranding machine is used to twist multiple steel wires into products. Prestressed steel strands also need to be continuously stabilized after forming. The final product is generally collected on a reel or reel-less.
Galvanized steel strands are usually used for messenger wires, guy wires, core wires or strength members, etc. They can also be used as earth wires/ground wires for overhead power transmission, barrier cables on both sides of roads, or structure cables in building structures. The commonly used prestressed steel strands are uncoated low-relaxation prestressed steel strands (uncoated steel strand for prestressed concrete), and there are also galvanized ones (galvanized), which are commonly used in bridges, buildings, water conservancy, energy and geotechnical engineering, etc. Unbonded prestressed steel strands (unbonded steel strand or monostrand) are commonly used in floor slabs, foundation engineering, etc.

The control tension force of the prestressed steel strand construction design refers to the tension of the steel strand before the anchor clamp after the prestressing is completed. Therefore, when calculating the theoretical elongation of the prestressed steel strand, the distance between the anchor points at both ends of the steel strand should be used as the calculated length of the steel strand. However, during the prestressing, the controlled tension force of the steel strand is controlled at the jack tool anchor. Therefore, for the convenience of control and calculation, the distance between the anchor points at both ends of the steel strand plus the working length of the steel strand in the tensioning jack is generally used as the calculated length of the theoretical elongation of the prestressed steel strand. During the prestressing of the steel strand, most of the exposed part of the steel strand is wrapped by the anchor and jack. The tension elongation of the steel strand cannot be directly measured on the steel strand. Therefore, the tension elongation of the steel strand can only be calculated by measuring the piston stroke of the tension jack. However, the amount of anchor retraction during the entire process of prestressing the steel strand should also be subtracted. The load-bearing capacity of the steel strand should be 4-6 times the total traction force .