The difference between carbon steel and stainless steel

It mainly refers to steel whose mechanical properties depend on the carbon content in the steel and generally does not add a large amount of alloying elements. It is sometimes also called plain carbon steel or carbon steel.
Carbon steel, also called carbon steel, refers to an iron-carbon alloy with a carbon content of less than 2%. In addition to carbon, carbon steel generally contains small amounts of silicon, manganese, sulfur, and phosphorus.
According to the use, carbon steel can be divided into three categories: carbon structural steel, carbon tool steel and free-cutting structural steel. Carbon structural steel is further divided into two types: building structural steel and machine-made structural steel;
According to the smelting method, it can be divided into open hearth steel, converter steel and electric furnace steel;
According to the deoxidation method, it can be divided into boiling steel (F), killed steel (Z), semi-killed steel (b) and special killed steel (TZ);
According to the carbon content, carbon steel can be divided into low carbon steel (WC ≤0.25%), medium carbon steel (WC0.25%-0.6%) and high carbon steel (WC>0.6%);
According to the phosphorus and sulfur content, carbon steel can be divided into ordinary carbon steel (higher phosphorus and sulfur content), high-quality carbon steel (lower phosphorus and sulfur content) and high-grade high-quality steel (lower phosphorus and sulfur content). Extra high quality steel.
Generally, the higher the carbon content in carbon steel, the greater the hardness and strength, but the lower the plasticity. Stainless acid-resistant steel is referred to as stainless steel. It is composed of two parts: stainless steel and acid-resistant steel. In short, steel that can resist atmospheric corrosion is called stainless steel, while steel that can resist chemical medium corrosion is called acid-resistant steel. Stainless steel is a high-alloy steel with more than 60% iron as the base and added elements such as chromium, nickel, and molybdenum.
When the chromium content in steel exceeds 12%, the steel will not easily corrode and rust in air and dilute nitric acid. The reason is that chromium can form a very tight chromium oxide film on the surface of steel, effectively protecting the steel from corrosion. The chromium content in stainless steel generally exceeds 14%, but stainless steel is not absolutely free from rust. In coastal areas or some places with serious air pollution, when the chloride ion content in the air is large, there may be some rust spots on the surface of the stainless steel exposed to the atmosphere, but these rust spots are limited to the surface and will not corrode the internal matrix of the stainless steel.

Generally speaking, steel with a Wcr content greater than 12% has the characteristics of stainless steel. Stainless steel can be divided into five categories according to its microstructure after heat treatment: ferritic stainless steel, martensitic stainless steel, austenitic stainless steel, Austenitic-ferritic stainless steel and precipitation carbonized stainless steel.

Stainless steel is usually divided into:
1. Ferritic stainless steel. Contains 12%~30% chromium. Its corrosion resistance, toughness and weldability increase with the increase of chromium content, and its chloride stress corrosion resistance is better than other types of stainless steel.
2. Austenitic stainless steel. It contains more than 18% chromium, and also contains about 8% nickel and a small amount of molybdenum, titanium, nitrogen and other elements. It has good comprehensive performance and can withstand corrosion from various media.
3. Austenitic-ferritic duplex stainless steel. It has the advantages of both austenitic and ferritic stainless steel and has superplasticity.
4. Tensite stainless steel. High strength, but poor plasticity and weldability.

The difference between carbon steel and stainless steel:
1. Different colors: Stainless steel contains more chromium and nickel metals, and its appearance is silvery. Carbon steel is mainly an alloy of carbon and iron, with relatively few other metal elements. The main color of its appearance is the color of iron, which will be much darker.
2. Different textures: Stainless steel contains many other metal elements and has a smooth surface. Carbon steel contains more iron and carbon, which has the essence of iron, and its surface is not as smooth as stainless steel.
3. Different magnetism: The surface of carbon steel is magnetic and can be absorbed by magnets. Stainless steel is not magnetic under normal circumstances and will not be attracted by magnets.
4. Different carbon elements: Carbon steel mainly refers to steel whose mechanical properties depend on the carbon content of the steel, and generally does not add a large amount of alloying metal elements. The carbon content WC is less than 2%. In order to maintain corrosion resistance, stainless steel has a lower carbon content. All are low, with the maximum not exceeding 1.2%.
5. Different alloy contents: Carbon steel contains very few alloy elements, only a small amount of silicon, manganese, sulfur and phosphorus. Stainless steel contains many gold elements, with the main chromium and nickel elements exceeding 12%.
6. Different corrosion resistance: carbon steel contains less chromium and has weak corrosion resistance, while stainless steel contains more chromium and nickel metal and has strong corrosion resistance.