The difference between carbon steel and stainless steel

Steel is a general term for iron alloys with a carbon content of between 0.02% and 2.04% by mass. The chemical composition of steel can vary greatly. Steels containing only carbon are called carbon steel (carbon steel pipe) or ordinary steel. In actual production, steel often contains different alloying elements depending on the application, such as manganese. Nickel, vanadium, etc.

Iron-carbon alloys containing less than 2% carbon are classified into carbon steel and alloy steel depending on the composition. According to performance and use, it can be divided into structural steel, tool steel and special performance steel.

Carbon steel mainly refers to steel in which the mass fraction of carbon is less than 2.11% and does not contain intentionally added alloying elements. Sometimes called carbon steel or carbon steel. Carbon steel does not contain effective alloying elements, and is an alloy containing iron, carbon and manganese as main elements. Mechanical properties are usually not as good as alloy steel.

Carbon steel is often referred to as carbon structural steel. According to the carbon content, it can be divided into low carbon steel, medium carbon steel and high carbon steel, and the carbon content is 0.2-0.7% or even higher. Carbon steels generally do not have corrosion resistance and are used in a variety of configurations due to their low cost (relative to stainless steel).

Stainless steel refers to an alloy steel that is resistant to weak corrosive media such as air, steam, water, and chemically etched media such as acids, alkalis, and salts. The corrosion resistance of stainless steel depends on the alloying elements contained in the steel. The basic alloying elements of stainless steel are nickel, molybdenum, titanium, niobium, copper, and nitrogen.

Stainless steel belongs to the category of alloy steel, a high alloy steel containing a large amount of chromium, and a large amount of nickel and a certain amount of titanium. The role of chromium is to make steel corrosion-resistant, and the role of nickel is to lower the austenitizing temperature of stainless steel. The total content of alloying elements can reach 10~28%, so it is a high alloy steel.

Common stainless steels are mostly austenitic stainless steels, such as 0Cr18Ni9. The carbon content is low, 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 addition of these alloying elements is greatly improved. It has antioxidant capacity and thermal stability, but these alloys are all precious metals. So the price is also very expensive.

Stainless steel is used in highly corrosive media, especially in foods with high requirements for ring conditions, and in pharmaceutical, daily chemical and other industries. Of course, the chemical industry is also widely used. However, austenitic stainless steel is most afraid of chloride ions, and the chloride ion control of water in the environment is very strict.

Carbon steel has low cost, is prone to rust, and has a short use time, while stainless steel is not easy to rust, has a long use time, and has a smooth surface.