QSM cable body

                        Cable is a linear flexible tension member with certain prestress, including steel strand, wire bundle, wire rope and other metal cables. At present, the commonly used cables for spatial structures in China are divided into two categories: steel strand cables and steel wire cables. With the material properties becoming more and more stable, the corrosion resistance and fatigue performance of the cable largely determine its safety and service life.

In China, more and more people have accepted the steel strand cable with good corrosion resistance and fatigue performance. In the newly built bridges, more and more bridges adopt the steel strand cable as the stressed cable.

Epoxy coated steel strand (steel wire) is a kind of pre-stressed high-strength material with superior anti-corrosion performance produced by electrostatic spraying process. In this process, the special epoxy powder is melted and evenly coated on the surface of steel strand or steel wire to form a dense physical protective layer. The mechanical and anti-corrosion properties of the finished product are better than those of the steel strand or steel wire after electro galvanizing. The cables made of epoxy coated steel strand (steel wire) are mainly used for external prestressing cables, cable-stayed bridge suspenders and large-scale public building structures.

The finished cable body of steel strand cables produced by our company is mainly epoxy sprayed unbonded tendons. With epoxy sprayed steel strand as the main material, the surface of the cable is coated with special anti-corrosion grease and then hot extruded with high-density polyethylene sheath to form a PE wrapped Unbonded Tendon. According to the stress demand, several unbonded tendons are arranged according to the stable structure of regular hexagon or hexagon, twisted to the left for 2 ~ 4 ° and then wrapped and fixed, and then hot extruded one or two outer PE sheath layers to finally become the cable body of the finished cable. The cable body has epoxy coating, special anti-corrosion grease layer, inner PE layer and outer PE layer, with no less than four layers of anti-corrosion performance, which is an important guarantee for the safe use of bridge cables.

● epoxy sprayed steel strand

       Epoxy sprayed steel strand is divided into single wire coating type and filling type. Epoxy resin powder is sprayed on the steel strand heated in advance by high-voltage electrostatic spraying method, and then melted, solidified and cooled to form a dense epoxy coating on the steel wire surface. The standard of "epoxy coated seven wire prestressed steel strand" is implemented. Its main advantages are: excellent chemical stability, good temperature stability, good adhesion to metal materials, good cathode decomposition resistance, excellent bending resistance, excellent impact resistance, good wear resistance and low oxygen permeability.

Because the center wire and six side wires of epoxy sprayed steel strand are coated with a dense epoxy resin protective film, the protective film gives the steel strand many beneficial properties, which can be applied in more severe corrosion environment. At the same time, because of its unique structure and excellent adaptability with QSM anchor fixture and tensioning equipment, epoxy sprayed steel strand is the first choice in the field of anti-corrosion engineering.

Single wire coated epoxy coated steel strand

(GB / t25823-2010 single wire coated epoxy coated prestressed steel strand)

Filled epoxy coated steel strand

(JT / t737-2009 filled epoxy coated steel strand)

● unbonded prestressed steel strand

The PE wrapped protective steel strand applied in post tensioned prestressed system is called unbonded prestressed steel strand, which is mainly divided into single wire coating type and filling type, which is in accordance with jg161-2016 standard of unbonded prestressed steel strand.

PE coated protective steel strand is made of epoxy sprayed steel strand as the main material and hot extruded high density polyethylene sheath after coating anti-corrosion grease on its surface, which is called unbonded prestressed steel strand.

Based on the excellent anti-corrosion performance of epoxy sprayed steel strand, as well as the weather resistance, wear resistance and full waterproof structure of anti-corrosion grease and hot extruded high-density polyethylene sheath, the PE coated steel strand has reliable protection function.

Unbonded prestressed steel strand is suitable for all kinds of steel strand cable systems such as low tower cable-stayed bridge and high tower cable-stayed bridge.

                                               Single wire coated unbonded prestressed steel strand and filled unbonded prestressed steel strand

Parameter comparison between epoxy sprayed strand and unbonded prestressed strand

● epoxy coated steel wire for cables

Since the first use of epoxy coating technology in the United States in the 1970s, it has been widely used in the United States, Japan, Europe, the Far East, the Middle East and other countries and regions. It is mainly used in cable-stayed bridge, arch bridge suspender, tie bar, suspension bridge sling and large-scale public building structure.

Epoxy coated steel wire is a kind of prestressed high strength steel wire material with better corrosion resistance than galvanized steel wire. The principle of the technology is to use the electrostatic spraying process, the special epoxy powder is melted and coated on the steel wire surface to form a dense protective film. It has the following characteristics:

1. The coating has strong adhesion, excellent alkali resistance, acid resistance, solvent resistance and other chemical properties, and its corrosion resistance is better than that of galvanized steel wire;

2. The coating process will not cause the loss of steel wire strength and other properties;

3. Because the bonding property of epoxy coated steel wire is better than that of galvanized steel wire, the combination of epoxy coated steel wire and cold cast anchor has better anchorage performance;

4. There is almost no waste discharge in the processing process of epoxy coated steel wire, which does not pollute the environment and is more environmentally friendly.

5. The technical performance index of epoxy coated steel wire meets the relevant requirements of GB / t25835-2010 "epoxy coated steel wire for cable".

Basic structure of QSM cable body

1. Cable type

2. Parameters of finished cable body

qsm-s8, qsm-s9 cable body

Qsm-s8 and qsm-s9 cable bodies are composed of high-strength steel wire bundles. The cross-section of the wire bundles is arranged closely in hexagonal or open angle hexagons, and is formed by left-handed slight twisting with the twist angle of 2 ° to 4 °. Outside the wire bundle, right-handed winding tape is continuously wound along the cable length, and then the polyethylene sheath is extruded. The sheath is a black single-layer structure or a double-layer structure with a black inner layer and a colored outer layer. The high strength polyethylene cable is generally called hot cable.

Schematic diagram of cable body of hot extruded polyethylene high strength steel wire