What is 321 Stainless Steel Round Bar? Properties, Uses, and Composition

What is 321 Stainless Steel Round Bar? Properties, Uses, and Composition

Are you looking for a specific type of steel bar to use for your industrial projects? If so, learning about the types of steel and their properties is crucial. 321 stainless steel round bar can be an excellent option when choosing which metal alloy is appropriate to meet the needs or expectations of any particular project. Explore all this alloy has to offer, including its chemical composition, properties, uses, and more, in this comprehensive guide!

Properties of 321 Stainless Steel Round Bar

321 Stainless Steel Round Bar is a titanium-stabilized austenitic stainless steel. It contains 18 – 20% chromium, 8 – 10.5% nickel, and 0.8 – 1.25% titanium, which increases its corrosion resistance compared to 304 Stainless Steel Round Bars. In addition, it has better thermal properties at elevated temperatures, improved strength when welded, and superior stress corrosion cracking resistance in adverse environments while remaining nonmagnetic even after welding and cold working processes are completed. Its higher creep and tensile strength offer greater flexibility than other grades of stainless steel round bars, making it ideal for high-temperature applications such as aircraft exhaust manifolds or turbochargers that may require frequent fabrication operations involving welding and forming. Additionally, its ability to resist scaling under high temperatures makes the 321 grade an excellent choice for formability under various corrosive conditions, including acidic chloride environments like those found near marine atmospheres or coastal industrial facilities where exposure to salt water is a potential issue.

Composition of 321 Stainless Steel Round Bar

321 stainless steel round bar is an austenitic chromium-nickel-stainless steel containing Titanium, which is added to enhance its intergranular corrosion resistance. The titanium content of 321 stainless steel imparts excellent resistance properties to the alloy in most oxidizing and reducing environments between 800oF (427oC) and 1500oF (816oC). Its composition typically contains 18% chromium, 9% nickel, 0.25%-0.7% titanium, and up to a maximum of 0.15% carbon, with trace amounts of other elements such as manganese and phosphorus as well as sulfur from ferrite or sulfide formation. This combination makes it resistant to chloride ion stress cracking corrosion at higher temperatures while providing a general increase in corrosion resistance compared to other alloys today.

Uses of 321 Stainless Steel Round Bar

The 321 stainless steel round bar is an excellent choice for many applications. It has exceptional corrosion resistance and strength. Its high chromium content gives it superior properties to other grades of stainless steel, allowing it to have better impact and abrasion resistance as well as good formability and weldability. Common uses include aerospace components, medical equipment, marine fittings, fasteners, pumps, valves, pressure vessels and tanks, and chemical processing equipment. This grade of stainless steel has excellent creep strength at elevated temperatures, so it’s often used in ovens and steam generation systems up to 1500°F (816°C). Moreover, due to its higher silicon and nitrogen content, many industrial furnaces also use this grade of stainless steel for their refractory lining materials due to its superb corrosion protection properties. Finally, the 316L/321 alloy boasts low thermal expansion rates, which make it perfect for water-based heating systems, including solar panel manufacturing processes where stability is a key requirement from the material used in production line machines and components.

Fabrication of 321 Stainless Steel Round Bar

Because of its excellent formability, 321 stainless steel is readily fabricated into different welding geometries and shapes. However, care should be taken during welding since 321 stainless steel can crack at temperatures lower than 700°C. Fabricated parts from 321 stainless steel should be subjected to annealing at 1600°F to support the welding procedures.


In conclusion, 321 stainless steel is an excellent choice of material in various industries, thanks to its excellent properties. Its resistance to high temperatures and corrosion and its excellent formability and weldability make it a popular choice in aerospace, chemical processing, and medical equipment manufacturing. Additionally, care must be taken during welding, and fabricated parts from 321 stainless steel should be subjected to an annealing procedure to enhance their overall mechanical strength. With these features, 321 stainless steel is an excellent choice of material for different applications.