Black annealed iron wire say goodbye to rust

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Black annealed iron wire is made from high-quality wire rod that has been drawn, annealed, and coated with a layer of black oil. Black annealed iron wire is commonly used in the construction projects as rebar tie wire or for temporary repairs or reinforcement. The black oil coating on the surface of black annealed iron wire effectively protects it from oxygen and moisture in the air, making the black annealed iron wire less prone to rusting and providing added safety for construction projects.

Black annealed iron wire say goodbye to rust

1.Impact of rusted iron wire on the construction project

2.Factors affecting the rusting of iron wire

3.A way to prevent the wire from rusting


►Iron wire is a common type of fastener, especially black annealed iron wire, which is widely used in the construction project. Black annealed iron wire has a broad range of applications in construction, not only using as rebar tie wire but also being used for temporary binding, repair and reinforcement, and as hangers for supports. In the construction tasks, there is great concern that rust in iron wire or other building materials,which can lead to construction project delays. So, what are some effective ways to prevent iron wire from rusting? Keep reading to find out.

1.Impact of rusted iron wire on the construction project

Do you know the impact of rusted iron wire on the construction industry? Rusted iron wire can have significant effects on the quality, safety, and overall performance of construction structures. 

Structural Integrity: Iron wire rusting can lead to a reduction in the load-bearing capacity of the iron wire, making the low carbon steel wire prone to breakage and resulting in potential building material collapse or fixation failure, leading to construction safety accidents.

Durability: Rusted iron wire is more prone to corrosion, reducing the lifespan and increasing maintenance costs. Over time, this can result in higher expenses for building owners.

Aesthetic Appeal: When iron wire rusts, it can negatively impact the overall look of a building or construction project. To address the issue of rusted iron wire, maintenance efforts such as painting or replacing the iron wire may be necessary.

Cost: The use of rusted iron wire can lead to increased material costs due to the need for replacement or repair of damaged iron wires. Labor costs may also rise as workers must spend more time dealing with rusty iron wire.

Project Delays: Rusted iron wire can lead to construction project delays, as builders may need to wholesale new iron wire and workers must replace the rusted iron wire in a timely manner. This can result in extended timelines for completion.

2.Factors affecting the rusting of iron wire

So what causes the iron wire to rust? First of all, we need to know "what kind of wire rusts?"

In daily life, it is easy to observe that cast iron, which is pure iron wire without any protective coating, is prone to rusting. This is because the iron reacts with oxygen in the presence of moisture, leading to oxidation and the formation of iron oxide, commonly known as rust.

So what are the other factors that make the iron wire easy to rust?

Temperature: Higher temperatures can accelerate the chemical reactions involved in rust formation. However, extremely low temperatures may slow down the process.

Acidity or pH Levels: Acidic environments can increase the rate of rust formation on iron wire surfaces. This is because acids can react with the iron, accelerating the oxidation process. Conversely, alkaline environments may slow down rusting.

Surface Condition: Rough or porous surfaces provide more sites for water and oxygen to come into contact with the iron wire, speeding up rust formation. Smoother surfaces may slow down the process by reducing the available iron wire surface area for oxidation.

Environmental Pollution: Airborne pollutants such as sulfur dioxide or nitrogen oxides can react with moisture in the atmosphere to form acidic compounds, which can accelerate rusting.

Coatings and Protection: Protective coatings such as paint or galvanization can inhibit rust formation by creating a layer between the iron surface and the surrounding environment. Proper maintenance of these coatings is essential to ensure continued protection against rust.

3.A way to prevent the wire from rusting

Based on the above information, we know that the simplest way to prevent rust on iron wire is to apply a protective coating on its surface. This layer serves as a barrier, isolating the iron from the external environment and preventing exposure to oxygen and moisture, which can trigger the oxidation process and lead to rust formation. 

For example, black annealed iron wire is created by high-temperature annealing of iron wire, followed by applying a layer of black oil on the surface of the annealed wire to protect the iron wire from the air's moisture and oxygen, thereby preventing the iron wire from rusting.

Some people might wonder"is annealed wire galvanized?" The answer is no. 

Black annealed iron wire is produced by coating the surface of iron wire with a layer of black oil, while galvanized iron wire has a zinc protective layer formed on its surface through electro-galvanization or hot-dipped galvanization. These two types of iron wire have different manufacturing processes. Black annealed iron wire is very common and cost-effective, making it well-suited for use in the construction tasks.

So what is the black annealed iron wire process? 

SUNSHINE Group 's production of black annealed iron wire generally involves five steps to ensure the manufacture of high-quality, rust-resistant black annealed iron wire.

1. Drawing: Firstly, high-quality iron wire rods(SAE1008) are drawn through a series of dies to reduce the wire diameter and achieve the desired thickness for the black annealed iron wire.This drawing process may be repeated multiple times to attain the desired wire diameter.

2. Annealing: After the iron wire has been drawn to the appropriate wire diameter, it undergoes annealing. Annealing involves heating the iron wire to a specific temperature, typically between 700°C to 900°C (1292°F to 1652°F), in a controlled atmosphere furnace. The iron wire is then held at this temperature for a certain period before being slowly cooled down. This annealing process relieves internal stresses in the iron wire, softening it and improving its flexibility and ductility.

3. Pickling: Following annealing, the iron wire can have its surface impurities removed by soaking in acid, which helps to smooth out the surface and make the iron wire easier to apply oil. 

4. Blackening: Depending on the application requirements, the black annealed iron wire may be coated with a thin layer of oil or wax to provide anti-corrosion and anti-rust capabilities.

5. Cooling and Coiling: After blackening, the black annealed iron wire is allowed to cool to room temperature before being coiled into spools or coils for storage and transportation.

Throughout the manufacturing process,the finished black annealed iron wire of SUNSHINE Group meets the required specifications and standards for tensile strength, diameter, surface finish, and other relevant properties.


Black annealed iron wire, after annealing and oil coating, is less susceptible to corrosion by oxygen and moisture in the air, making the black annealed iron wire less prone to rusting. This makes black annealed iron wire particularly suitable for use in outdoor construction projects. However, black annealed iron wire is not completely immune to rusting. Galvanized iron wire offers superior rust and corrosion resistance compared to black annealed iron wire, but it also comes with a higher price tag.

SUNSHINE Group can provide high-quality black annealed iron wire and galvanized iron wire in various sizes. Please feel free to contact us for more information.




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