？
In the stainless steel market, engineers and metalworkers often ask what is special about AISI 321 steel (also known as SUS 321 and UNS S32100)? This stainless steel grade has an outstanding combination of advantages that can meet the needs of many applications.
AISI 321 steel is an austenitic type of stainless steel, with a nickel-chromium content of 25 percent and a titanium addition of five percent. Titanium is an important element in the process of tempering this steel, especially when it is welded into a worksite. It is used in applications which require resistance to strong oxidizing media, as well as to moderately carburizing atmospheres.
The addition of titanium in AISI 321 steel helps to form titanium carbides along grain boundaries in the welded metal. These carbides form a hard, fine grain structure which gives this steel a kind of toughness that conventional austenitic steels do not possess. Its strength is even greater than that of standard grade 304 stainless steel.
At the same time, AISI 321 steel is more resistant to scaling at higher temperatures than conventional austenitic steels, and is far superior to grade 304 in resisting oxidation at temperature up to 1600°F (871°C). In the range of 1500°F - 1600°F (816°C - 871°C), the oxidation resistance of AISI 321 steel is considerably better than that of other stainless steel grades, especially grade 304.
These advantages make AISI 321 steel nicely adoptable for welding, where its improved formability lies in its favor. AISI 321 steel can be said to be both corrosion and heat resistant, and welders should keep in mind that weldments aren’t subject to post-weld heat treatment. AISI 321 steel is resistant to intergranular corrosion in normal temperatures, and even in extreme temperatures, where it can stand up to temperatures up to 1500°F (816°C).
Due to its performance qualities, AISI 321 steel is used often in high temperature industrial areas and other applications that require resistance to corrosive environments. It is effective in areas of moderate to low chloride ion concentration.
In conclusion, AISI 321 is an excellent choice for applications that require resistance to strong oxidizing agents as well as carburizing atmospheres, and its benefits are seen in high temperature industrial areas that require corrosion resistance. The titanium addition in AISI 321 steel provides superior weld strength and toughness, and temperature scaling and oxidation resistance. The increased resistance to corrosion and scaling makes AISI 321 steel the ideal choice for applications in areas such as deicing and chemical processing.
