What is Carbon Steel?
Primarily refers to steel whose mechanical properties are largely determined by its carbon content and which typically does not add a significant amount of alloying elements. When referring to iron-carbon alloys with a carbon content of less than 2% WC, it is also known as plain carbon steel or carbon steel.
Carbon steel typically includes small amounts of silicon, manganese, sulfur, and phosphorus in addition to carbon. Carbon steel’s hardness and strength increase with increasing carbon content while its plasticity decreases.
Classification of carbon steel:
- Depending on its use, carbon steel can be divided into three categories: carbon structural steel, carbon tool steel, and free-cutting structural steel. Architectural structural steel and machine-made structural steel are the additional two categories of carbon structural 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); 2. According to the smelting method, it can be divided into open hearth steel, converter steel, and electric furnace steel
- Based on the carbon content, carbon steel can be classified as low carbon (WC 0.25%), medium carbon (WC 0.25%-0.6%), and high carbon (WC > 0.6%)
- Carbon steel can be classified into ordinary carbon steel (higher phosphorus and sulfur), high-quality carbon steel (lower phosphorus and sulfur), high-quality high-quality steel (lower phosphorus and sulfur), and super high-quality steel depending on the amount of phosphorus and sulfur present.
What is Stainless Steel ?
Stainless steel is a type of steel that is resistant to acid. Acid-resistant steel and stainless steel make up its two components. In a nutshell, stainless steel is steel that can withstand atmospheric corrosion, and acid-resistant steel is steel that can withstand corrosion from chemical media. With more than 60% iron as the matrix and alloying elements like chromium, nickel, and molybdenum added, rusty steel is a high-alloy steel.
Steel is difficult to corrode and rust in the air and dilute nitric acid when the chromium content is above 12%. The reason is that chromium has the ability to create an extremely thin layer of chromium oxide on the surface of steel, effectively shielding it from corrosion. Despite having a chromium content that typically exceeds 14%, stainless steel does not rust completely. The stainless steel surface exposed to the atmosphere may have some rust spots in coastal areas or other areas with significant air pollution when the chlorine ion content is high, but these rust spots are only on the surface and won’t erode the stainless steel’s internal matrix.
Generally speaking, steel with a WCr content higher than 12% possesses stainless steel properties. Ferritic stainless steel, martensitic stainless steel, austenitic stainless steel, austenitic-ferritic stainless steel, and precipitation carbide stainless steel are the five categories that stainless steel can be categorized into after heat treatment.
What are the different types of stainless steel?
The most popular steel grades, 304 and 316, are austenitic. This type of steel has 16–26% chromium and up to 35% nickel. Stainless steel with the highest level of corrosion resistance is often austenitic, which cannot be heat treated to harden. This family of stainless steel is also ductile, nonmagnetic, and hard. If a metal can change shape without losing strength, it is considered to be ductile.
Grade 304, usually known as 18/8 due to its 18% chromium and 8% nickel concentration, is the most widely used austenitic steel. Austenitic steels are frequently used in the aerospace and food processing industries.
Physically, austenitic steel is similar to ferritic and martensitic steels in most respects. The variation in chemical composition is the cause.
Ferritic
Ferritic steels are heat hardenable because of their low carbon content (less than 0.2%). Only cold working to a reasonable degree of hardness is possible. As a result, they have lower corrosion resistance than austenitic steels. Standard ferritic steels contain a chromium concentration of 10.5-27% and no nickel. The most popular grades of ferritic stainless steel are 409, 430, 439, and 441. Ferritic steel is commonly used in architectural applications as well as auto trim.
Martensitic
Martensitic steels, which typically contain 11.5-18% chromium and up to 1.2% carbon (and occasionally nickel), can be hardened through heat treatment. These steels are magnetic, have a fair amount of corrosion resistance, good strength, and ductility. They usually attend classes at the 400-level. Martensitic steel is used to make surgical instruments, cutlery, and tools.
Austenitic-ferritic (duplex)
Duplex steels, which evenly combine austenitic and ferritic stainless steels, contain chromium in the range of 21-27%, copper in the range of 1.05-3%, and molybdenum in the range of 0.05-5%. Due to the mix of components, duplex steels are more resistant to corrosion than either austenitic or ferritic steel. As a result, storage tanks and other containers for the transfer of chemicals are typically made of duplex steel.
Precipitation Hardening
Precipitation-hardening stainless steel is notable for its strength. Aluminum, copper, and niobium make up the final 3-5% of the mass of the steel, along with nickel and chromium, which together make up 15–17.5% of the steel’s mass. Precipitation-hardening steel has equal corrosion resistance to austenitic steel. This kind of steel can be toughened by aging it at a temperature that is quite low. Metalworkers use it to create lengthy shafts for pumps or valve spindles.
What is the differences between carbon steel and stainless steel:
- Different colors: Stainless steel is primarily bright silver on the outside and is richer in chromium and nickel metals. Other metal elements are relatively insignificant in carbon steel, which is primarily an alloy of carbon and iron. Iron is the primary color of the outer surface, though it will be much darker.
- Different textures: Stainless steel has a smooth surface and many other metal elements, whereas carbon steel has the same amount of iron and carbon as stainless steel but a rougher surface.
- Different magnetism: Carbon steel has a magnetized surface that can draw magnets. Under normal circumstances, stainless steel is not magnetic and is not drawn to magnets.
- Different carbon elements: The term “carbon steel” primarily refers to steel whose mechanical properties depend on the carbon content of the steel and which typically does not add a significant amount of alloy metal elements, where the carbon content WC is less than 2%. Stainless steel contains carbon to maintain corrosion resistance. The maximum is 1.2%, both of which are low.
- Different alloy content: Silicon, manganese, sulfur, and phosphorus, which are the few alloying elements found in carbon steel, are also in small amounts. The main chromium and nickel elements in stainless steel are over 12%, and the metal contains a lot of gold elements.
- Different corrosion resistance: Stainless steel contains more chromium-nickel metal, which has a strong corrosion resistance, than carbon steel, which has fewer alloying elements and weaker corrosion resistance.