Method for manufacturing rustproof coated steel strand

Abstract

To provide a method for producing rustproof-coated steel strand of low relaxation at low cost.The method comprises the following process: Steel strand A formed by laying up a plurality of steel wires 1, 1... is threaded through synthetic resin extruders 4 and 5 to subject the strand A to rustproof-coating treatment and fill a thermoplastic synthetic resin material in the voids formed among the respective steel wires along with coating the outer circumference of the strand A with the thermoplastic synthetic resin material. In this process, after forming the strand A by laying up the plurality of steel wires 1, 1..., the strand A is subjected to blueing treatment, and the strand A heated by the blueing treatment is threaded through the synthetic resin extruders 4 and 5 to subject the strand A to the rustproof-coating treatment.

Description

technical field [0001] The present invention mainly relates to a method of manufacturing a PC wire rod or a tension chord used for a tension girder, etc., and an antirust-coated steel strand. Background technique [0002] In the past, in the manufacture of antirust coated steel strands used for PC wires or tension chords for string beams, a plurality of steel core wires are arranged around a core wire composed of steel core wires. The side wires are twisted into steel strands by a stranding machine, and transferred to other anti-rust processing places for anti-rust coating treatment. [0003] In the manufacturing process of steel strands, after stranding each steel core wire, the steel strands should be heated to 300°C∽350°C and blued to improve the tensile strength, elastic limit, Fatigue limit, etc., by heating the steel strand to about 300°C to 350°C and applying a tensile load to give a certain permanent deformation, and then cooling it (so-called heat stretching treatm...

AI Technical Summary

Problems solved by technology

[0007] However, when using the above-mentioned conventional technology, since the wire stranding process and the antirust coating process are completed in different places, it is necessary to transport the product, that is, the steel strand, between the two work places, which requires expenses, which makes the cost of the product The main reason for the rise, and the scale of the steel strand must be removed during the operation (rust removal treatment), etc.

[0008] In addition, when performing anti-rust processing, since the steel strands that have been subjected to bluing treatment or heat-stretching treatment are reheated, the slack will be increased, and the effect of heat-stretching treatment will be impaired, and in order to reheat, Requires expensive heating equipment, which increases operating costs

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