Steel pipes stand out due to their excellent durability. Right? Their use is common in water supply lines and oil and gas transportation. However, there are two types of steel pipes: black iron and black steel, which are very popular. Due to their popularity, people start the black iron pipe vs black steel pipe debate, considering them direct competitors.
Interestingly, some consider black iron pipes made solely of iron. First things first, the black iron pipe is not made of iron; it is made of mild steel. However, these two types are made of different kinds of steel. In this article, I’ll compare black iron and black steel pipes head-to-head. This comparison will help you choose the right steel types for your custom needs.
Basic Rundown of Black Iron and Black Steel Pipe
Before discussing differences, let’s first look at the basics of both black iron and black steel pipes.
Black iron pipes are mainly made of mild steel (type of carbon steel). On the other hand, black steel pipes are made with carbon steel (with high carbon content). Due to higher carbon content, the black steel is stronger and more durable than black iron pipes. Both look black due to oxide layers.
Interestingly, the black iron pipes have a long history. They were first developed and used back in the late 1800s. At that time, there were no other reliable options, but black iron was in high demand. Black steel pipes are newer development that emerged in the 20th century. They are quickly replacing the black iron pipes due to their better performance and durability.
There is a misconception that black iron pipes are made only of iron, which is incorrect. Remember, this pipe consists of steel (mild steel), which is an alloy. It consists of iron, carbon, manganese, and many other alloy elements, not just iron. However, iron is a central alloying element, accounting for over 95% of mild steel.
The black steel pipes are made of carbon steel (a type of steel). Both of these pipes look black, not because of the additional paint coat. Instead, their black look comes during the manufacturing process. As I said earlier, both pipes are made of iron. So, this iron reacts with oxygen, forming iron oxide layers on its surface. This layer protects the surface of these pipes but gives them a matte black appearance.
Differences Between Black Iron Pipe and Black Steel Pipe
In the section below, I’ll discuss the key differences between these steel types. Understanding these distinctions will help you choose the right steel pipes for your custom needs. So, let’s begin!
1- Composition & Major Material
As I said earlier, both of these pipes are made of steel. Steel is an alloy containing iron as its primary constituent. It means both pipes contain a higher proportion of iron. However, they differ in terms of their carbon content. Remember, steel has different types. The black iron pipes are made of mild steel (low-carbon steel).
The carbon content in this steel type is very low ( around 0.25%). On the other hand, the black steel pipe is made of carbon steel. This steel type has slightly higher carbon content (0.60% – 1.00%). Additionally, the iron content is higher in black iron pipes than in black steel pipes. However, the proportion of other alloy elements is almost the same. Those include manganese, silicon, sulfur, and more.
2- Corrosion Resistance & Durability
Black steel pipes are superior in terms of corrosion resistance. Why? The reason is that this steel pipe is made of carbon steel, having a higher carbon content. This higher carbon proportion gives the steel pipe decent strength and hardness. As a result, it becomes resistant to moisture and other environmental conditions.
This pipe type resists rust and remains in good condition for years. On the other hand, black iron pipes have a low carbon content because they are made from mild steel. So, they are weaker and cannot withstand moisture and other conditions well. Due to their superior rust and corrosion resistance, black steel pipes are more durable and long-lasting.
Quick Highlight: Their average lifespan is around 60 to 80 years. On the other hand, black iron pipes can only last around 30 to 40 years with regular maintenance. Remember, the black steel pipes can also withstand extreme pressure. So, they are an ideal option for applications where fluid pressure remains high.
3- Physical Appearance & Pressure Rating
In appearance, both steel pipes look similar. They have a dark, matte finish and black color as their name indicates. People think their black color is due to the paint or other colors. However, these pipes don’t have a coating, but have a layer of oxide. This layer forms when iron reacts with oxygen to form iron oxide.
This oxide layer protects the surface of these pipes, but makes them look black. However, the black steel pipes have a smoother surface. On the other hand, the black iron pipes feel rougher when you touch their surface. Regarding pressure rating, I consider black steel pipe a superior option. Why? The reason is that black steel pipes have higher carbon content.
This higher carbon content makes these pipes harder and increases their tensile strength. As a result, they can withstand higher flow pressure. The black iron pipes are only suitable for low-pressure applications. This is due to their lower carbon content, which reduces their tensile strength.
4- Strength & Ease of Installation
The black steel pipes offer greater strength than their counterparts. The reason is that these pipes are made of carbon steel with a higher carbon content. Higher carbon content increases the tensile strength and hardness of these pipes. As a result, they become resistant to mechanical stress. The black iron pipes are weaker because they have a lower carbon content.
However, the black iron pipes are easier to install than black steel pipes. The reason is that black iron pipes are made of mild steel, which is softer. Its cutting, threading, and welding are easier than those of carbon steel used in black steel pipes. cutting and welding of black steel pipes are more challenging, which affects their ease of installation.
5- Safety & Impurities
Generally, both of these steel pipes are safe. They won’t explode, causing safety issues out of nowhere. However, I consider black steel pipes safer than black iron pipes. These pipes are durable and less likely to leak or burst. Additionally, these pipes don’t have impurities. Remember, impurities in the composition can weaken the pipes.
Black iron pipes are prone to leakage, especially when old and used under medium pressure. Additionally, their composition contains impurities, which further weaken these pipes. This small leakage can be an issue if pipes transport gases or oil. Remember, neither of these pipes will burst or cause accidents.
6- Repair & Maintenance
Black iron pipes are generally easier to repair. As I said earlier, these pipes are softer and easier to cut and weld. If there is any defect, you can easily cut the affected section or piece and weld a new piece in its place. This way, you can easily repair the damaged or defective parts. However, the black steel pipes are harder and difficult to cut.
So, their repairs require specialized tools and machines. However, the black steel pipes require little to no maintenance. Why? That’s because of their excellent strength and durability. They don’t weaken over time, resulting in no maintenance cost. However, black iron pipes can weaken over time and even corrode. So these pipes need regular maintenance.
7- Cost/Affordability & Applications
Black iron pipes are inexpensive and readily available. Their low pricing makes them an ideal option for budget-friendly projects. Remember, these pipes are made of mild steel, which is very inexpensive. As a result, the cost of overall black iron pipes is low. On the other hand, black steel pipes are premium and expensive.
But better durability, strength, and quality make their higher price worth it. These black iron pipes are rated for low pressure. It means they should only be used in applications with less pressure. People use it for gas and sprinkling systems. On the other hand, black steel pipes are stronger and are used in heavy-duty applications.
You’ll see them in the transport of oil, gases, and so on. Here is the table showing the application comparison of black iron and black steel pipes:
| Black Iron Pipe | Black Steel Pipe |
| Natural gas lines (indoor) | Oil and gas transport pipelines |
| Fire sprinkler systems | Industrial water and steam lines |
| Low-pressure air systems | High-pressure systems and hydraulic lines |
| Heating and cooling (HVAC gas supply) | Structural and mechanical applications |
| Indoor residential use | Outdoor and industrial environments |
| Temporary or low-stress piping | Permanent, heavy-duty installations |
Conclusion: Which One to Choose, Black Iron Pipe or Black Steel Pipe?
Still confused and want my opinion on black iron vs black steel pipes?
My verdict goes in favor of black steel pipes. Why? That’s because of the excellent performance, durability, and high-pressure rating of these black steel pipes. Their higher tensile strength makes them a superior option over the black iron pipes. However, you should choose black iron if you’re on a tight budget.
If you use specific applications that don’t involve high-pressure fluid, black iron pipes are suitable. They are easier to install and repair, and they perform adequately for low-pressure water or gas systems. However, when it comes to quality, black steel pipes are matchless and are premium. Their performance in oil, gas, water, and steam transport will impress you.