Carbon steel pipe is often referred to as carbon structural steel. It is iron, carbon and manganese as the main elements except C. It is not divided into other alloying elements. It is mainly divided into 10# seamless steel pipe, 20 # seamless steel pipe, 45# seamless steel pipe, of course, C is also controlled to a certain extent, and the hardness is larger than pure iron. Carbon steel has low cost, is prone to rust, and has a short use time, and is used in various structures and pipes that do not have any corrosion resistance.
Stainless steel pipe refers to alloy steel containing less than or equal to 13% Cr and not in the atmosphere. There are many types of stainless steel, such as ferritic stainless steel, austenitic stainless steel, and martensitic stainless steel. Different stainless steels have different resistance to corrosion and different corrosion resistance to different media. It is also different in terms of magnetism. Carbon steel is magnetic, and stainless steel generally does not have magnetic or magnetic properties.
The stainless steel tube contains a large amount of chromium, and some contain a large amount of nickel and a certain amount of titanium. The role of chromium is to make steel corrosion-resistant. Nickel is the main alloying element for the formation of austenitic stainless steel, but the role of nickel can only be fully demonstrated when it is combined with chromium. If pure nickel is used, a pure austenite single-phase structure is required in low-carbon nickel steel, and the nickel content needs to be more than 24%. In fact, when the nickel content needs to reach 27%, the corrosion resistance of the stainless steel pipe can be remarkably improved. , so there is no nickel as an alloying element in the stainless steel tube.
Common stainless steels are mostly austenitic stainless steels, such as 304, 316L, 321 and so on. The carbon content is lower, but the alloying element content is above 20%, of which the chromium is 18-20%, the Ni content is 8-10%, and there are elements such as vanadium, molybdenum and titanium. The stainless steel is used for corrosiveness. In the medium, especially in foods with high requirements for ring conditions, pharmaceuticals, daily chemical cosmetics and other industries, most of them are used. Of course, the chemical industry is also widely used. However, austenitic stainless steel is afraid of chloride ions and is very strict in controlling the chloride ions of water in the environment.
Carbon Steel Pipe vs Stainless Steel Pipe:
1. Chemical composition
Carbon steel pipe is mainly composed of iron and carbon, of which the carbon content is between 0.06-1.5%, and also contains a small amount of silicon, manganese, sulfur, phosphorus and other elements.
The stainless steel tube is mainly composed of chromium, nickel, molybdenum and other elements, and also contains a small amount of carbon, manganese, silicon and other elements. Therefore, the chemical composition of stainless steel pipes is more complex than that of carbon steel pipes.
2. Corrosion resistance
The main feature of stainless steel pipe is its resistance to corrosion, and its ability to maintain surface brightness and integrity for a long time. Because it contains elements such as chromium, a layer of dense chromium oxide film is formed, which can prevent external substances such as oxygen and water from entering the interior of the metal, thereby achieving the effect of preventing oxidation and corrosion.
Carbon steel pipes, on the other hand, do not have this ability to resist corrosion and often require coating protection to prevent corrosion.
3. Mechanical strength
Carbon steel pipe is a pipe with good mechanical properties, high strength and wear resistance, so it is often used to manufacture parts and components of mechanical equipment.
The mechanical properties of stainless steel pipes are relatively poor, mainly because they contain more alloying elements, which easily lead to problems such as particle precipitation and grain boundary corrosion.
Detailed explanation of stainless steel pipe:
Stainless steel pipe is unlike other steels in that it resists corrosion. One percent of the chromium in this form of steel, the corrosion resistance of stainless steel pipes is due to the presence of a large amount of chromium in the steel, which forms an invisible, thin and adherent oxide layer that makes the surface passive, in order to form this A passive oxide layer, the steel should contain enough chromium, it needs to be kept in an oxygen-rich environment, the passive layer protects the underlying metal by covering air and water, if scratched the oxide layer will heal automatically, the chromium content of the stainless steel pipe should exceed A certain weight.
In addition to chromium and carbon, stainless steel tubes contain silicon, phosphorus, manganese, sulfur, nickel and molybdenum.
Stainless steel tubes contain a certain weight of carbon. Increasing the carbon content above this value can be made to reduce the corrosion of the steel and reduce the chromium to create a passive oxide layer. According to its crystal structure, stainless steel tubes can be divided into austenite, ferrite, martensite, precipitation hardening, and due to some alloying elements, stainless steel tubes can become non-magnetic.
Detailed explanation of carbon steel pipe:
Apart from stainless steel pipes, all other carbon steel pipes contain carbon, manganese, silicon and copper, this type of steel can be further divided into low carbon steel pipes, medium carbon steel pipes and high carbon steel pipes according to the carbon content, the corrosion resistance of this alloy Much lower than that of stainless steel pipes. Carbon steel pipe should not be used in more corrosive environments.
Carbon steel pipes are much cheaper than stainless steel pipes. Its main alloying element is relatively expensive chromium is the main alloying element of stainless steel pipes. As the carbon content increases, the shape of this steel becomes harder and harder, which reduces ductility , to change the desired mechanical properties of this steel by heat treatment.
The above is the difference between stainless steel pipes and carbon steel pipes. When selecting pipes, you need to choose according to specific application scenarios and requirements. Customers who have certain requirements for the product should choose stainless steel pipes. Stainless steel pipes have excellent corrosion resistance, anti-aging, anti-explosion, anti-rust, environmental protection, safety, reliability, and can be used for a long time.
