Analyze the differences between different types of stainless steel from a professional perspective
Stainless steel is a very popular material due to its wide variety. Architects and contractors often use it in the construction industry. We can also see stainless steel used in automobile manufacturing or sewage treatment. Additionally, stainless steel is an excellent material that can be used to optimize a clean, sterile environment, such as kitchens and hospitals. Below is an introduction to the different types of stainless steel for reference.
ferritic stainless steel
Ferritic stainless steel contains less carbon and its microstructure is similar to carbon steel and low alloy steel. Compared to other types of stainless steel, typically only thinner profiles can be used due to the lack of toughness of the welds. Nonetheless, ferritic stainless steels are commonly used by contractors in areas where welding is not required. Furthermore, ferritic steel cannot be hardened by heat treatment. But when molybdenum is added, you can also use it in seawater or other corrosive conditions. Ferritic stainless steels are also magnetic but not as formable as austenitic stainless steels. On the other hand, steelworkers often choose ferritic stainless steel because it resists corrosion and is less prone to cracking.
Austenitic stainless steel
Austenitic stainless steel is one of the most common types of stainless steel on this list. Its microstructure includes nitrogen, nickel and manganese elements. The structure of austenitic stainless steel is the same as that of ordinary steel. But formability and weldability only occur at higher temperatures. In addition, the corrosion resistance of austenitic stainless steel can be improved by adding nitrogen, chromium and molybdenum. Although it cannot be hardened by heating, austenitic stainless steel has the useful property of maintaining a certain degree of toughness and ductility once it has hardened to high strength. Typical stainless steels are prone to stress corrosion cracking, while austenitic stainless steels with higher nickel content increase their resistance to stress corrosion cracking. Austenitic stainless steel is non-magnetic on the surface, but will exhibit some magnetic response depending on its composition.
martensitic stainless steel
Similar to ferritic stainless steels, martensitic stainless steels have higher chromium and carbon content. Like carbon and low-alloy steels, martensitic stainless steels can be tempered and hardened. Martensitic stainless steel has moderate corrosion resistance and high strength. Since it is one of the magnetic stainless steel types, it has lower formability and weldability. In most cases, companies use martensitic stainless steel for plate products that require long-term use.
Duplex stainless steel
Duplex stainless steels have a microstructure of half austenitic and half ferrite, giving them greater strength than these types of stainless steels. It is also resistant to stress, corrosion and cracking. "Scarce" duplex stainless steel with similar corrosion resistance to regular Austin stainless steel. However, its resistance to stress and corrosion and cracking have been improved. "Superduplex" stainless steel also has better corrosion resistance and strength than ordinary austenitic stainless steel. Additionally, they are solderable as long as care is taken to use the soldering material at the appropriate temperature. Duplex stainless steels are also magnetic stainless steels and have moderate formability.
Precipitation hardening increases the strength of different types of stainless steel
Precipitation hardening of stainless steel can create very high strengths when elements such as niobium, copper and aluminum are added. On the other hand, it develops strength by forming very fine particles in the steel matrix when properly "aging" heat treated. Finally, you can create some complex shapes when you work with this type of steel. However, a good level of resistance is required before the final aging treatment. The corrosion resistance of precipitation hardened steel is also comparable to that of ordinary austenitic steel.
