Black steel pipes are usually made of carbon steel or alloy steel, which have extremely high mechanical strength and anti-corrosion properties.
How to blacken steel? With black paint for steel on the surface, the object presents a deep black tone, leaving the viewer with a calm and atmospheric feeling.
Compared with conventional metal pipes, the durability of black steel pipes is more excellent, especially under extreme environmental conditions.
Black Steel Pipes
Black Steel Pipe Common Specifications
The production and application of black steel pipes follow a series of international and regional standards, such as ASTM, ISO, and GB. These standards specify the size, materials, test methods, and application requirements of black steel pipes to ensure product quality and safety.
ASTM A53：Suitable for general purpose welding or seamless common standard black steel pipe.
ISO 3183：Suitable for pipeline transportation of oil, natural gas and other fluids.
GB/T 3091：Standard for welded black steel tubes for low pressure fluid transport.
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Black Steel Pipes Size
In ASTM standards, the common size of black steel pipe is this:
Outside diameter: 1/8″ to 72″ (3.2 mm to 1828.8 mm).
Wall thickness: Usually proportional to the outer diameter of the pipe, can be customized according to the specific needs of the customer.
Length: Usually a fixed length (e.g., 6 meters, 12 meters) or customized according to customer requirements.
Manufacture of Black Steel Pipe
The manufacturing process of black pipe mainly has the following two methods.
Manufacturing Process of Seamless Black Steel Pipe
a. Hot rolling manufacturing:
- Billet preheating: First, the solid billet of carbon steel needs to be preheated to a high-temperature state.
- Perforation: Under high-temperature conditions, the preheated billet is placed into the perforating equipment so that it becomes a hollow cylinder shape.
- Extension and rolling: The perforated billet is then extended and rolled by several rolling units to meet predetermined size and thickness requirements. Shape adjustment: The size and shape are further adjusted precisely by a tuning mill.
- Shape adjustment: Further precise size and shape adjustment with a rolling mill.
- Cooling: Remove the tube from the furnace and begin cooling.
b. Cold drawing manufacturing:
- When smaller sizes and tighter dimensional tolerances are required, the cold drawing process may be a viable option.
- Cold drawing means that after the tube has been thoroughly cooled, it is drawn to the exact size required by the cold drawing machine.
Manufacturing Process of Welded Black Steel Pipe
a. Prepare raw materials:
- Cutting steel plates: First, large steel plates are cut into strips of the desired width.
- Forming: The steel strip is rolled into a tube shape in the forming machine.
b. Welding:
- Resistance welding: In the welding equipment, the two ends of the steel pipe are connected by resistance welding (ERW – resistance welding).
- Weld inspection: To confirm the quality of the weld, it is necessary to go through a series of inspection procedures.
c. Cooling and cutting:
- Cooling: The welded pipe must be cooled in the air.
- Cutting: After cooling is completed, the pipe is cut to the length specified by the customer.
d. Surface and end treatment:
- Burrs: Remove burrs from the inside and outside surfaces of the weld.
- End processing: The end can be chamfered according to actual requirements.
e. Inspection and packing:
- Quality inspection: Including non-destructive inspection to ensure that the weld and pipe quality is up to standard.
- Surface treatment: Sandblasting and other methods to enhance its corrosion resistance.
- Packaging: Packaging the pipes that meet the quality requirements.
Both types of black steel pipes can be subjected to additional heat treatment, cold working or coating treatment according to actual needs to meet the specific application needs.
Black Steel Pipe Conclusion
Black steel pipe with its unique corrosion resistance, high strength, cost-effective and other properties, established its irreplaceable position in the field of materials science. In the modern social development and industrial progress, black tube plays a fundamental and key role, becoming one of the important pillars of modern civilization.
1. Is black steel same as carbon steel?
Carbon steel has a higher carbon content than ordinary steel, but black steel gets its name because it is coated with black iron oxide. Black steel is formed by layering malleable cast iron, carbon steel is formed in a seamless process.
2. What is cheaper black pipe or galvanized pipe?
Compared with the two, the cost of black iron pipe is lower than that of galvanized pipe. This is due to the absence of zinc coating. In contrast, during the manufacturing process, the black iron tube is covered with iron oxide.
3. Is Black steel stronger than steel?
Yes, high carbon steel is generally stronger than low carbon steel. Because high carbon steel has a higher carbon content, usually between 0.60% and 1.0%, low carbon steel has a lower carbon content, usually between 0.05% and 0.25%.
