Stainless steel pipes and carbon steel pipes are both good choices for a variety of uses, so it may be hard to know which one is right. By getting down to the basics of what steel pipe is and how it’s used, you should be able to better determine which will fit your needs.

Both carbon steel pipes and stainless steel pipes belong to metal steel pipes, but the content of metal elements contained in them is different, which also leads to the characteristics of stainless steel pipes that are more corrosion resistant than carbon steel but have a higher purchase cost. Typically, both have the same basic elements iron and carbon. The difference is carbon steel pipe has a 10.5% alloy content while stainless steel pipe has a chromium content of 10.5 % and more than it. Also, its essential difference is distinct physical characteristics.

1. What Are Carbon Steel Pipes Used For?

Carbon steel pipes are made of steel ingots or solid round steel through the perforation into capillary tubes and then made by hot rolling, cold rolling, or cold drawing. Carbon steel pipe has an important position in my country's steel pipe industry.

Carbon steel pipe is used for liquid, gas, and steam services both above- and belowground services. It is not recommended for use in corrosive services but may be used in caustic services.

Carbon Steel Pipe Types

Carbon steel pipes are divided into two types: hot-rolled and cold-rolled steel pipes.

• Hot-rolled carbon steel pipes: Hot-rolled carbon steel pipes are divided into general steel pipes, low and medium pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, geological steel pipes, and other steel pipes.
• Cold-rolled carbon steel pipes: In addition to general steel pipes, low and medium pressure boiler steel pipes, high-pressure boiler steel pipes, alloy steel pipes, stainless steel pipes, petroleum cracking pipes, and other steel pipes, cold-rolled carbon steel pipes also include carbon thin-walled steel pipes, alloy thin-walled steel pipes, stainless thin-walled steel pipes, and special-shaped steel pipes.

2. What Are Stainless Steel Pipes Used For?

Stainless steel pipes are made of acid-resistant and heat-resistant steel billets, which are heated, pierced, sizing, hot-rolled, and cut.

Stainless steel pipe is hollow long round steel and is primarily used in piping systems for the transport of fluids or gases, which is also widely used in petroleum, chemical, medical, food, light industry, machinery and instrumentation, and other industrial transportation pipelines and mechanical structural parts. In addition, when the bending and torsion strength are the same, the weight is lighter, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also often used as furniture and kitchen utensils.

Stainless Steel Pipe Types

Stainless steel pipes are divided into different types according to different manufacturing processes and shapes.

• Classified by process: stainless steel seamless steel pipe and stainless steel welded steel pipe (seam steel pipe) are basically two categories.
• Classified by the shape of the outer diameter of the steel pipe: round pipes and special-shaped pipes. Round steel pipes are widely used, but there are also some square, rectangular, semi-circular, hexagonal, equilateral triangle, octagonal, and other special-shaped steel pipes.

3. Carbon Steel Pipes vs Stainless Steel Pipes

Common carbon steel pipes are Q195 and Q235. Carbon steel can also be called magnet alloy steel, except for carbon and iron, generally, it also contains a small amount of silicon, manganese, sulfur, and phosphorus. Stainless steel is chromium-nickel steel, in addition to carbon and iron, there are other metal elements such as chromium, nickel, and copper. The chromium content in the steel pipe over 12.5% will form a protective film (passivation film) on the surface of the steel pipe, so as to achieve the effect of anti-corrosion. Therefore, the main difference between the two is corrosion resistance. Carbon steel pipes are easy to rust, while stainless steel pipes are corrosion-resistant steel.

Stainless steel pipe is lustrous and comes in various grades that can increase the chromium in the alloy until the steel finish is as reflective as a mirror. To the casual observer, carbon steel pipe and stainless steel pipe are easy to distinguish. Carbon steel pipe is dull, with a matte finish that is comparable to a cast iron pot or wrought iron fencing.

Stainless steel is a unique form of steel that does not corrode. It gets this property by employing chromium as a special hardening agent. With the use of chromium, stainless steel has the basic properties of steel with significantly increased corrosion resistance. Like carbon steel, stainless steel also reacts to oxygen in the air to form an oxide layer. However, rather than form an iron oxide layer, it forms a chromium oxide layer. Iron oxide is a volatile molecule that continues to aid in oxidation which is the problem we get on carbon steel. However, chromium oxide is inert – it forms a protective layer that prevents further oxidation. For this reason, stainless steel pipes can be used in open systems and also applications requiring high levels of hygiene, such as the food and brewing industries.

How To Choose Steel Pipes For Your Pipeline?

Here are a few factors that affect the selection of carbon steel pipes or stainless steel pipes.

(1) Substance

What is your pipeline used to transport? Gas or liquid? If you are transporting corrosive items, such as chemicals or saltwater, if so, you will need a metal that does not react so easily. This usually means choosing stainless steel pipe, but carefully check the characteristics of the material you are using to see what it will react with.

(2) Temperature

Will your pipes be exposed to extreme temperatures? Stainless Steel has lower thermal conductivity than Carbon steel. Carbon steel pipes are known for their ability to withstand high heat and are good for things like steam pipes. However, if you are working with extreme cold—for example, transporting cryogenic liquids—a different grade of pipe will be necessary.

(3) Cost

Fortunately, both stainless steel pipes and carbon steel pipes can be very affordable. Carbon steel pipe is frequently ranked as the least expensive steel for piping, but stainless steel pipe is also usually right behind. However, for carbon steel pipes, the cost of stainless steel pipes is higher, and the higher the chromium content, the more expensive the price.

(4) Appearance

If your pipes will be visible and appearance is a consideration for you, knowing the finish of these steels will help. Stainless steel usually has a shine to it and holds up if exposed to weather and other elements. Carbon steel is darker and has a matte finish look. This may also start to corrode if exposed, deteriorating in appearance. And stainless steel is preferred for many consumer products and can be used decoratively in construction, while carbon steel is often preferred in manufacturing, production, and in projects where the steel is mostly hidden from view.