15.2 steel strand Manufacturers consider steel strands to be finished steel products composed of several steel wires twisted together, also known as prestressed steel strands, unbonded steel strands, galvanized steel strands, etc. High-carbon steel coils are accepted, cold-drawn into wires after surface treatment, and then wires with a certain lifespan goal are twisted into strands according to the layout of the steel strand, omitting the stress stabilization process.

15.2 steel strand manufacturers believe that for durability, steel strands are coated with metallic or non-metallic coatings, such as galvanized and epoxy resin coatings. To increase the adhesion to concrete, the appearance may have notches, etc. After twisting, the prestressed steel strand drawn from the mold undergoes a compression process in a mold, the layout becomes denser, and the surface becomes increasingly suitable for anchor grip. This allows unbonded prestressed steel strands to accept ordinary prestressed steel strands and be coated with anticorrosion grease or paraffin wax and high-density polyethylene.

　　Precautions for using 15.2 steel strand according to manufacturers:

　　1. Heating and deformation of prestressing steel bars are strictly prohibited during use to avoid reducing the mechanical properties of the prestressing steel bars.

　　2. Welding is strictly prohibited during use because the weld strength is far lower than that of the steel itself, and wire breakage is easily caused during tensioning.

　　3. 15.2 steel strand manufacturers believe that prestressing steel bars should be cut using a toothless cutter (abrasive wheel). Electric and gas welding cutting can easily damage the surface around the steel. At the same time, local heating at the end significantly reduces performance.

　　4. When prestressing steel wire is used as reinforcing steel, its bending radius should not be less than 3 times the diameter of the wire.

　　5. Steel strands in axiless coil packaging should be released from the inner coil tap in a vertical state, and the drawn steel strands are spring-like and automatically straighten. Direction: The spiral direction after spring tapping is consistent with the twisting direction of the strand; otherwise, it will twist or strand.

　　6. 15.2 steel strand manufacturers believe that the twisting direction of mining steel strands is generally left-handed, and right-handed twisting should be specified in the contract; otherwise, it will directly affect the cooperation with the anchor.

　　7. The quality of prestressing steel wire upsetting is not directly related to the quality of the steel wire itself, but excessive strength will be detrimental to the quality of steel wire upsetting.

　　Acceptance points for mining steel strands according to 15.2 steel strand manufacturers:

　　1. 15.2 steel strand manufacturers believe that the acceptance of prestressing steel bars should comply with relevant national standards, and the testing instruments should be legally calibrated measuring instruments and comply with the provisions of the testing standards.

　　2. When checking quality issues, pay attention to whether the following items meet the requirements:

　　(1) Whether new national standards and testing methods are used for acceptance.

　　(2) Whether the tonnage of the testing machine is appropriate; whether the measurement is accurate; whether the fracture of the steel is sticky; whether the nominal area is used to calculate the strength.

　　(3) Whether the bending clamps of the bending testing machine comply with national standards, and whether the surface finish, hole height, and test bending angle of the clamps comply with the standards.

　　(4 )15.2 steel strand Manufacturers believe that the elongation of steel bars should be measured using a sharp standard marking tool to measure the distance, and the surface of the steel bars should not be damaged.

　　(5) Whether the steel itself has serious rust or surface damage caused by artificial storage.