321 stainless steel is based on Cr-Ni-Ti Austenitic stainless steel, and it is similar to 304 stainless steel, but with better resistance to intergranular corrosion resistance due to the addition of titanium element, and high temperature strength. The addition of titanium is effective in controlling the formation of chromium carbide.
321 stainless steel has excellent high-temperature stress rupture properties and high-temperature creep properties, its mechanical properties are better than 304 stainless steel, and it is also heat-resistant steel, better in high temperatures than 316L.
Grade 321 is the grade of choice for applications in the temperature range of up to about 900 °C, combining high strength, resistance to scaling, and phase stability with resistance to subsequent aqueous corrosion.
Titanium as the stable element exists in 321 stainless steel, it is a variation of 304 stainless steel, 321 stainless steel in different temperatures and different concentrations of organic acid and inorganic acid, especially has good wear and corrosion resistance in the oxidizing medium for the manufacture of the wear-resistant acid containers and equipment lining, pipeline.
321 Stainless Steel Chemical Composition(%)
| Standard | Grade | C | Mn | Cr | Ni | Mo | N | Other |
|---|---|---|---|---|---|---|---|---|
| ASME II A SA-240 | 321 | ≤0.08 | ≤2.00 | 17.0-19.0 | 9.0-12.0 | ≤0.10 | ||
| ASTM A240 | 321 | ≤0.08 | ≤2.00 | 17.0-19.0 | 9.0-12.0 | ≤0.10 | Ti 5 X C Min – 0.70 Max | |
| EN 10028-7 | 1.4541 | ≤0.08 | ≤2.00 | 17.0-19.0 | 9.0-12.0 | |||
| EN 10088-2 | 1.4541 | ≤0.08 | ≤2.0 | 17.0-19.0 | 9.0-12.0 | |||
| EN 10088-4 | 1.4541 | ≤0.08 | ≤2.0 | 17.0-19.0 | 9.0-12.0 | |||
| GOST 5632-72 | 08X18H10T | ≤0.08 | ≤2.0 | 17.00-19.00 | 9.00-11.00 | ≤0.35 | ≤0.10 | |
| GOST 5632-72 | 12X18H10T | ≤0.12 | ≤2.0 | 17.0-19.0 | 9.0-11.0 | ≤0.35 | ≤0.10 |
321 Stainless Steel Grade Mechanical Property
| Standard | Grade | Rp0.2 | Rp1.0 | Rm | Elongation | Rockwell | HB |
|---|---|---|---|---|---|---|---|
| MPa | MPa | MPa | % | ||||
| ASME II A SA-240 | 321 | ≥ 205 | ≥ 515 | ≤ 217 | |||
| ASTM A240 | 321 | ≥ 205 | ≥ 515 | ≤ 95HRB | ≤ 217 | ||
| EN 10028-7 | 1.4541 | ≥ 220 | ≥ 250 | 520-720 | ≥ 40 | ||
| EN 10088-2 | 1.4541 | ≥ 220 | ≥ 250 | 520-720 | ≥ 40 | ||
| EN 10088-4 | 1.4541 | ≥ 220 | ≥ 250 | 520-720 | ≥ 40 | ||
| GOST 5632-72 | 08X18H10T | ≥ 235 | ≥ 250 | ≥ 535 | ≥ 40 | ||
| GOST 5632-72 | 12X18H10T | ≥ 230 | ≥ 260 | 540-670 | ≥ 45 |
321 Stainless Steel Equivalent Grades
| AISI | UNS | DIN | EN | JIS | GB |
|---|---|---|---|---|---|
| 321 | 32100 | 1.4541 | X6CrNiTi18-10 | SUS321 | 0Cr18Ni10Ti |
321 Stainless Steel Physical Properties
| Density | Melting Point | Specific Heat | Thermal Conductivity [W/(M·K)] | Coefficient Of Expansion （ 10-6/K ） | Electrical Resistivity | Elastic Modulus |
|---|---|---|---|---|---|---|
| G/Cm3 | （ ℃ ） | [J/(Kg·K)] 0~100 ℃ | 100 ℃ | 0~100 ℃ | （ Ω·mm2/M | KN/Mm2 |
| 8.03 | 1398~1427 | 500 | 16.3 | 16.6 | 0.72 | 193 |
Corrosion Resistance
321 stainless steel exhibits good general corrosion resistance, and excellent resistance to intergranular corrosion after exposure to temperatures in the chromium carbide precipitation range of 800 – 1500°F (427 – 816°C), 321 resists oxidation to 1500°F (816°C) and has higher creep and stress rupture properties than alloys 304 and 304L.
Heat Resistance
Good oxidation resistance in intermittent service to 900°C and in continuous service to 925°C. These grades perform well in the 425-900°C range, and particularly where subsequent aqueous corrosive conditions are present, they also possess good low-temperature toughness.
Heat Treatment
Heat temperature range is limited to 950-1120°C and cool rapidly for maximum corrosion resistance, it cannot be hardened by heat treatment.
Dual Certification
Dual 321/321H stainless steel is usually used for high-temperature applications.
Notes
- Perform not well in chloride solutions, even in small concentrations, or in sulfuric acid service
- Grade 321 stainless steel does not polish well so that not recommended for decorative applications
- Excellent weldability by all standard fusion methods, both with and without filler metals
321/321H Stainless Steel Comparison
Grade 321H is a modification of 321 with higher carbon content, to provide improved high-temperature strength.
| C | Si | Mn | P | S | Cr | Ni | Ti | N | |
|---|---|---|---|---|---|---|---|---|---|
| 321 | 0.08 | 1.00 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 9.0-12.0 | 5 X C Min – 0.70 Max | 0.10 |
| 321H | 0.04 -0.10 | 1.00 | 2.00 | 0.045 | 0.030 | 17.0-19.0 | 9.0-12.0 | 4 X C Min – 0.70 Max | – |
| Tensile Strength(Mpa) | Yield Point(Mpa) | Elongation(%) | Hardness(HRB) | |
|---|---|---|---|---|
| 321 | 515 | 205 | 40 | 95 |
| 321H | 515 | 205 | 40 | 95 |
Related References
- ASTM A240/ASME SB240, Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications
- ASTM A480, Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel Plate, Sheet, and Strip
- EN 10088-2, Stainless steels. Technical delivery conditions for sheet/plate and strip of corrosion-resisting steels for general purposes
- EN 10088-3, Stainless steels. Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion-resisting steels for general purposes
- EN 10088-4, Stainless steels. Technical delivery conditions for sheet/plate and strip of corrosion-resisting steels for construction purposes
- EN 10088-5, Stainless steels. Technical delivery conditions for bars, rods, wire, sections and bright products of corrosion-resisting steels for construction purposes
- ASTM A249, Standard Specification for Welded Austenitic Steel Boiler, Superheater, Heat-Exchanger, and Condenser Tubes
- ASTM A213, Standard Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes
- ASTM A312, Standard Specification for Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes
- ASTM A276, Standard Specification for Stainless Steel Bars and Shape