SS 321 / UNS S32100 / W.Nr. 1.4541
Stainless Steel 321
Stainless steel 321 (also known as Alloy 321 or SS 321), is a highly popular titanium-stabilized grade of stainless steel known for its exceptional performance in high-temperature environments. Ideal for use in applications that demand temperatures ranging from 1000-1600°F, this alloy is specially treated to provide optimum resistance against intergranular corrosion and polythionic acid stress corrosion cracking.
To enhance its high-temperature performance, a stabilizing treatment is performed at 1550-1650°F and cooled in air, making Stainless steel 321 an ideal choice for various industries, including aerospace, medical equipment, and chemical processing. This alloy is also known for its excellent welding characteristics, as it can be welded using all common welding methods, including submerged arc welding. When it comes to welding filler materials, AWS ER347 bare wire and E347 covered electrodes are the most appropriate options.
Stainless steel 321 is known for its machinability, which is rated at 45% relative to AISI B1112. This makes it an ideal choice for various machining operations, and its similarity to 304 stainless steel only adds to its versatility and versatility.
Industries and Applications
Stainless Steel 321 is a highly versatile and widely used type of stainless steel known for its excellent performance in high-temperature environments. The unique properties of this alloy make it a popular choice for various industries, including:
Aerospace: Due to its excellent high-temperature resistance, Stainless steel 321 is widely used in aerospace applications, including aircraft exhaust systems, engine components, and structural parts.
Medical Equipment: The high-temperature resistance and non-toxic nature of Stainless steel 321 make it an ideal material for use in medical equipment, such as surgical instruments and implants.
Chemical Processing: The ability of SS 321 to resist corrosion in harsh chemical environments makes it a popular choice for use in chemical processing equipment, such as reaction vessels, heat exchangers, and piping systems.
Oil and Gas: The high-temperature resistance and corrosion resistance of Stainless steel 321 make it an ideal material for use in oil and gas exploration and production equipment, including valves, fittings, and wellheads.
Food and Beverage: The non-toxic and non-reactive nature of Stainless steel 321 make it a popular material for use in food and beverage processing equipment, such as storage tanks, mixers, and conveyors
Resistance to Corrosion
SS 321, is a highly popular type of stainless steel that is renowned for its excellent resistance to corrosion and its ability to withstand high-temperature environments. The unique combination of its high-temperature stability and resistance to corrosion makes it an ideal choice for a wide range of industries.
One of the most significant benefits of Stainless steel 321 is its ability to resist intergranular corrosion, even in high-temperature environments. This is due to its titanium stabilization, which helps to prevent the formation of chromium carbides at the grain boundaries. Additionally, Stainless steel 321 is highly resistant to polythionic acid stress corrosion cracking, making it an ideal choice for use in harsh chemical environments.
In terms of general corrosion resistance, Stainless steel 321 is highly resistant to many types of corrosives, including acids, alkalis, and salts. This makes it an ideal material for use in applications where corrosion resistance is a top priority, such as in chemical processing equipment, oil and gas exploration and production equipment, and food and beverage processing equipment.
Fabrication and Heat Treatment
Stainless steel 321 widely used due to its excellent fabrication and heat treatment properties. The unique combination of its high-temperature stability and resistance to corrosion makes it an ideal choice for a wide range of industries.
Fabrication of Stainless steel 321 is relatively straightforward, and it can be easily formed, machined, and welded using standard fabrication techniques. This alloy has a machinability rating of 45% relative to AISI B1112, making it similar to 304 stainless steel in terms of machinability. It is also readily welded by all common methods, including submerged arc welding, and appropriate weld fillers include AWS ER347 bare wire and E347 covered electrodes.
In terms of heat treatment, Stainless steel 321 is designed for use in high-temperature environments, and it has a stabilizing treatment at 1550-1650°F that can be used to provide optimum resistance to intergranular corrosion and polythionic acid stress corrosion cracking. The stabilizing treatment is followed by an air cool, and this treatment provides excellent high-temperature stability, making it an ideal material for use in applications that require resistance to high-temperature environments.
Stainless Steel 321 – Applicable Specifications
| Form | ASTM | ASME | Other |
|---|---|---|---|
Stainless Steel 321 Plate & Sheet |
A240 | SA240 | NACE MR0175/ISO 15156, EN 10088-2 |
Stainless Steel 321 Bar |
A276 | SA276 | NACE MR0175/ISO 15156, EN 10088-3 |
Stainless Steel 321 Pipe & Tube |
A312 | SA312 | NACE MR0175/ISO 15156, EN 10216-5 |
Stainless Steel 321 Fitting |
A403 | SA403 | NACE MR0175/ISO 15156 |
Stainless Steel 321 Wire |
A580 | SA580 | NACE MR0175/ISO 15156, EN 10088-3 |
Stainless Steel 321 Forging |
A479 | SA479 | NACE MR0175/ISO 15156 |
Stainless Steel 321 Bolting |
A193 | SA193 | NACE MR0175/ISO 15156 |
Stainless Steel 321 Flange |
A182 | SA182 | NACE MR0175/ISO 15156 |
Stainless Steel 321 Welding Electrode |
AWS A5.9 ER347 | – | – |
Common Trade Names
Stainless steel 310, also known as Alloy 310 or SS 310, is a heat-resistant and highly alloyed austenitic stainless steel that is commonly referred to by its trade names, such as Altemp 310, Nicrofer 6020, and Austral Wright Metals 310. These trade names are recognized in various industries for their high-temperature resistance, good weldability, and excellent oxidation resistance.
Key Properties
(in annealed condition)
| Property | SS 321 |
|---|---|
| Tensile Strength (MPa) | 515 min |
| Yield Strength (MPa) | 205 min |
| Elongation | 40 min |
| Hardness (HRB) | 95 max |
Chemical Composition (%)
| Chemical Element | SS 321 |
|---|---|
| Carbon (C) | 0.03 max |
| Manganese (Mn) | 2 max |
| Phosphorus (P) | 0.045 max |
| Sulfur (S) | 0.03 max |
| Silicon (Si) | 1 max |
| Chromium (Cr) | 18 – 20 |
| Nickel (Ni) | 11 – 15 |
| Molybdenum (Mo) | 3 – 4 |
| Nitrogen (N) | 0.1 – 0.2 |
| Iron (Fe) | Balance |
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