iron wire black wire black annealed iron wire building tie wire building binding wire steel bar 铁丝 黑铁丝 黑退火铁丝 建筑捆扎丝 建筑绑丝钢筋

Black wire, also known as annealed wire, fire-warmed wire, and binding wire, has a black or gray surface. It is mainly exported for use as binding wire and tying wire, and is also a semi-finished product or raw material in various wire mesh applications within China.

       Thicknessing:Common wire diameters range from 0.7 mm to 4 mm (BWG 22 to BWG 8) (see attached wire diameter comparison table).

       Features:Soft, highly resilient, easy to shape, with a wide range of applications.

     Purpose:Annealed silk is widely used in various fields such as construction binding, product packaging, handcrafts, and daily life. In the screen weaving industry, annealed silk serves as the raw material for producing black silk fabric, as well as an intermediate material for producing galvanized silk threads.

     Packaging<t_XXXXXXXXX> <t_XXXXXXXXX>We weigh the items according to the customer's requirements and required weight, then wrap them in plastic film, and finally pack them in woven bags or linen bags.

Black wire is made ofrodafter drawingCold Drawing WireFormed through annealing, the rod and cold-drawn wire have been introduced earlier. Today, we will mainly discuss the annealing process.

During cold drawing, the structure and mechanical properties of the steel wire change, leading to work hardening. As cooling occurs, this process increases the tensile strength, hardness, and elastic limit of the wire, while reducing the elongation and cross-sectional shrinkage rates. Due to work hardening, once the deformation reaches a certain level, the cooling and processing properties of the wire significantly decline, making further drawing unsuitable. In such cases, intermediate heat treatment is required to restore various processing properties; this process is known as annealing.

The purpose of annealing is to reduce hardness and improve machinability: eliminate residual stress, stabilize dimensions, reduce deformation and crack tendencies; refine grains, adjust the microstructure, and remove microstructural defects.
The annealing process isafter drawingCold Drawing WirePlace in an annealing tank or annealing furnace,Heat slowly to a certain temperature.MaintainEnough timeThen cool down at an appropriate speed.After removing it, the annealing purpose can be achieved. The annealing time is generally around 2 to 12 hours. The wire after annealing is called annealed wire.

The production process is basically completed, and then packaging begins. Before packaging, there is a crucial step that cannot be skipped.Fuel injection. Oil injections are typically lubricating oil, rust preventive oil, or engine oil. They ensure that the threads do not rust over time and keep the surface shiny. Finally, it depends on the customer's requirements.Weighing, 50kg, 25kg, 5kg, 3kg, 1kg, etc., in a roll. Then wrap it with a layer of plastic film and another layer of burlap or woven bag. Finally, after being inspected by factory inspectors, if it passes the tests, it can be shipped from the factory to the customer.