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Galvanized steel pipe vs black steel pipe: Which one is right for your project?

Galvanized steel pipe vs black steel pipe: Which one is right for your project?

BlogDate: 08-07-2024 by: Ngoc Cam

Topics regarding the characteristics of galvanized steel pipe vs black steel pipe are frequently compared because these two are common materials in construction applications, piping systems, and various manufacturing fields. Although both are types of steel pipes, comparing their characteristics reveals significant differences.

To begin, let's explore the key differences between galvanized steel pipe and black steel pipe? Which type of pipe is best suited for contractors in specific applications? Read the article now and answer these questions with MRS Steel in the following lines!

The characteristics of galvanized steel pipe vs black steel pipes differ significantly
The characteristics of galvanized steel pipe vs black steel pipes differ significantly

Definition and structural composition of galvanized steel pipe vs black steel pipe

The main distinction of galvanized steel pipe vs black steel pipe is its appearance, specifically the presence of a zinc coating. Galvanized steel pipes are essentially formed from carbon steel but the manufacturer applies an additional layer of zinc to enhance their resistance to corrosion and oxidation. Therefore, when used over a long period, the zinc layer acts as a sacrificial layer and will rust before the oxidizing agents reach the base steel layer.

On the other hand, black steel pipes do not undergo the galvanizing process. They are identified by their characteristic dark or matte surface. This coloration is formed by a layer of black iron oxide, which results from the reaction between oxygen and iron during the production process. Although galvanized steel pipe and black steel pipe have significant differences in their external characteristics, they both share the same carbon steel core.

Galvanized and black steel pipes have same steel core layer but differ in surface treatment
Galvanized and black steel pipes have same steel core layer but differ in surface treatment

Comparing the properties of galvanized steel pipe vs black steel pipe

Based on the differences in their coatings, galvanized steel pipe and black steel pipe each have their own advantages and disadvantages in terms of corrosion resistance, strength, and durability. Furthermore, each type has its specific purposes and suitability for various industrial applications.

Corrosion resistance

The corrosion resistance of galvanized steel pipe is rated better than that of black steel pipe due to the zinc coating on the surface. Specifically, the galvanized coating acts as a sacrificial anode, interacting with H2O molecules to form zinc hydroxide, which helps prevent the contact of water and air, thereby protecting the steel from oxidation and corrosion.

In contrast, the surface of black steel pipe is only covered with a layer of iron oxide as a result of the reaction between the iron in the steel and the air. This coating does not significantly prevent corrosive agents, and their structure is not durable and can be easily broken down when exposed to salt or acids.

One way to protect black steel pipes from oxidation is to place them in dry environments or areas with stable climatic conditions with low levels of salt and acidity. Additionally, to enhance rust resistance, black steel pipes can be coated with paint or other protective layers after installation.

Galvanized steel pipe has higher corrosion resistance through its zinc layer
Galvanized steel pipe has higher corrosion resistance through its zinc layer

Steel strength and durability

In terms of steel strength, both types of steel originate from carbon steel, so they generally contain carbon content ranging from 0.25% to 0.55%, along with a few other alloys such as manganese, phosphorus, etc. This amount is sufficient to ensure a balance between hardness for good load-bearing capacity and flexibility in machining applications.

Galvanized steel pipe and black steel pipe both have natural heat resistance and can withstand pressures up to 150 PSI, as both types of steel have melting points up to 1370 degrees Celsius. Therefore, under natural environmental conditions or in harsh environments, the temperature will never reach levels that could damage the steel structure, except in cases where machining processes generate temperatures exceeding their endurance limits.

However, the thicker the coating, the better the steel product can withstand all weather conditions. Specifically, the zinc coating can extend the lifespan of steel pipes up to 50 years. When comparing durability, there is a significant disparity of galvanized steel pipe vs black steel pipe. Due to the lack of a protective coating, black steel pipes, although having good mechanical properties initially, tend to deteriorate and lose durability over time during use.

Both steel types have good heat resistance with the melting point to 1370 degrees Celsius
Both steel types have good heat resistance with the melting point to 1370 degrees Celsius

Flexibility in machining

In machining applications, workers often prefer black steel pipe vs galvanized steel pipe because this steel type does not have a zinc coating. Therefore, they can be easily cut, bent, and welded without worrying about damaging the protective layer. In contrast, galvanized steel pipe has a zinc coating, which can pose a risk of poisoning to the worker when machining, especially during welding.

Additionally, black steel pipes are produced through a hot rolling and welding process, which creates a seam along the length of the pipe. During pipe connection operations, black steel pipes are easier to work with compared to galvanized steel pipes because the seam makes them extremely easy to install without the need for welding.

Without zinc layer in surface, black steel pipe can be easily cut, bend and welded
Without zinc layer in surface, black steel pipe can be easily cut, bend and welded

Applications of galvanized vs black steel pipe

Fields such as construction, pipeline systems, and automotive manufacturing are the three most common application sectors for galvanized steel pipe and black steel pipe. However, within these fields, each type of steel demonstrates distinct and appropriate aspects!

Construction

The robustness providing excellent load-bearing capacity and resistance to corrosion has made galvanized steel pipe and black steel pipe are crucial materials for construction projects. However, in outdoor structures of infrastructure like railings, fences, and scaffolding frames, contractors prefer galvanized steel pipe vs black steel pipe due to its ability to withstand weather impacts and ensure long-term durability.

On the other hand, black steel, known for its strong load-bearing capacity and ease of fabrication and assembly, is often used for indoor structures where there is less direct exposure to weather, such as framework, temporary structures, or water piping systems. Currently, black steel pipes are more readily available on the market compared to galvanized steel pipes because their manufacturing process is typically simpler and less costly.

Galvanized steel pipe is used for outdoor structures in construction projects
Galvanized steel pipe is used for outdoor structures in construction projects

Piping systems

Piping systems are considered the most common application for galvanized steel pipe and black steel pipe. Particularly when considering water piping systems and other liquids such as oil pipelines, waste pipelines, chemical pipelines, etc., manufacturers prefer galvanized steel pipe vs black steel pipe due to its smooth zinc coating surface, which helps prevent the accumulation of mineral deposits that could clog water pipes.

Although black steel pipes are more common, they are often not prioritized in applications for fluid piping systems because this type of steel lacks a protective coating. As a result, black steel pipes are susceptible to corrosion and rust when exposed to fluids. Instead, black steel pipes are used for propane or natural gas piping systems to residential and commercial buildings. Additionally, this steel type is also used in fire sprinkler systems because this type of steel has better heat resistance and fire resistance compared to galvanized steel pipes.

Galvanized is applied for liquid piping systems while black steel pipe is common in natural gas piping systems
Galvanized is applied for liquid piping systems while black steel pipe is common in natural gas piping systems

Other common applications

Black steel pipe and galvanized steel pipe both have numerous important applications in various industries beyond construction and piping systems. In the automotive industry, galvanized steel pipe can be used in exhaust systems of vehicles due to their corrosion resistance or for components exposed to external environments. Additionally, galvanized pipes are also prevalent in the energy sector, where they are used in support structures for solar panel arrays because of their ability to withstand harsh weather conditions.

Black steel pipes, known for its ease of fabrication and high mechanical strength, are used in mechanical structures within the mechanical engineering industry. Moreover, they find application in manufacturing furniture frames and tables in the interior design sector. Their ease of fabrication supports easy bending and cutting operations, facilitating the creation of diverse designs with high durability.

Galvanized steel pipes are used in the energy sector as supports for solar panels
Galvanized steel pipes are used in the energy sector as supports for solar panels

Galvanized steel pipe vs black steel pipe: Which material costs more?

Comparing the cost of galvanized steel pipe vs black steel pipe, generally, black steel pipes are cheaper because in the manufacturing process of this material, they do not undergo the galvanizing stage. The absence of a protective zinc coating reduces raw material costs, making this type of steel a more economical choice for applications that do not require high corrosion resistance.

Black steel pipes will help optimize project costs better than galvanized steel pipes
Black steel pipes will help optimize project costs better than galvanized steel pipes

Save time and cost on galvanized and black steel pipe purchases with MRS Steel

In summary, galvanized steel pipes are the perfect choice for applications requiring high durability and corrosion resistance, especially projects in harsh environmental conditions. On the other hand, black steel pipes are a sensible choice due to their combination of mechanical strength, durability, and cost-effectiveness. The selection between galvanized and black steel pipe will depend on the specific technical requirements of the project along with considerations of cost.

Through this article, MRS Steel aims to provide readers with a comparative perspective on the properties of galvanized steel pipe vs black steel pipe, thereby assisting in the selection of the most suitable material for their projects. If you are looking for high-quality galvanized or black steel pipes that meet all standards and have clear origins, please contact MRS Steel via WhatsApp: +84 76 911 2358 or email: vanloc@mrssteel.com.vn.