321 Stainless Steel Round Bar / Hot Rolled Black Bar Cold Rolled
Bright Stainless Steel Bar
321 Stainless Steel Bar
UNS S32100 (Grade 321)
321 stainless steel bar, also known as UNS S32100 and Grade 321, is
primarily comprised of 17% to 19% chromium, 12% nickel, .25% to 1%
silicon, 2% maximum manganese, traces of phosphorus and sulfur, 5 x
(c + n) .70% titanium, with the balance being iron. With regards to
corrosion resistance, 321 is equivalent to Grade 304 in the
annealed condition and is superior if the application involves
service in the 797° to 1652° F range. Grade 321 combines high
strength, resistance to scaling and phase stability with resistance
to subsequent aqueous corrosion.
Grade 321 Stainless Steel Datasheet
The following tables and lists give grade 321 stainless steel
datasheet and specification including chemical composition,
physical properties and mechanical properties, machinability, heat
treatment, welding, etc.
Chemical Composition
SS 321 stainless steel chemical composition is listed in the
following table based on cast analysis.
| Chemical Composition, % |
| ASTM Type | AISI Type (UNS) | C, ≤ | Si, ≤ | Mn, ≤ | P, ≤ | S, ≤ | Cr | Ni | N, ≤ | Other Elements | Notes |
| ASTM A240/A240M | 321 (UNS S32100) | 0.08 | 0.75 | 2.00 | 0.045 | 0.03 | 17.0-19.0 | 9.0-12.0 | 0.10 | ≥ Ti 5×(C+N), ≤ 0.70 | Plate, Sheet, and Strip for Pressure Vessels |
| ASTM A276A/276M | 1.00 | – | Stainless Steel Bars and Shapes |
| ASTM A580/A580M | – | ≥ Ti 5×C | Stainless Steel Wire |
| ASTM A959 | 0.10 | ≥ Ti 5×(C+N), ≤ 0.70 | Wrought Stainless Steels |
| ASTM A473 | – | ≥ Ti 5×C | Stainless Steel Forgings |
| ASTM A314 | – | ≥ Ti 5×(C+N), ≤ 0.70 | Billets and bars for forging |
| ASTM A240/A240M | 321H (UNS S32109) | 0.04-0.10 | 0.75 | 2.00 | 0.045 | 0.03 | 17.0-19.0 | 9.0-12.0 | 0.10 | ≥ Ti 4x(C+N), ≤ 0.70 | Plate, Sheet, and Strip |
| ASTM A959 | 1.00 | 0.10 | Wrought Stainless Steels |
| ASTM A312/A312M | TP321 (UNS S32100) | 0.08 | 1.00 | 2.00 | 0.045 | 0.03 | 17.0-19.0 | 9.0-12.0 | 0.10 | ≥ Ti 5×(C+N), ≤ 0.70 | Stainless Steel Pipes |
| TP321H (UNS S32109) | 0.04-0.10 | 1.00 | 2.00 | 0.045 | 0.03 | 17.0-19.0 | 9.0-12.0 | 0.10 | ≥ Ti 4x(C+N), ≤ 0.70 |
AISI 321 Stainless Steel Properties
The tables below list AISI 321 stainless steel properties,
including physical and mechanical properties.
Physical Properties
AISI 321 steel physical properties are given in the following
lists, including density, thermal expansion, elastic modulus,
thermal conductivity, specific heat capacity and electrical
resistance.
Notes:
- 10-6·K-1 = 10-6/K
- 1 Ω·mm²/m = 1 μΩ·m
- 1 g/cm3 = 1 kg/dm3 = 1000 kg/m3
- 1 GPa = 1 kN/mm2
- 1 MPa = 1 N/mm2
| SS321 Physical Properties |
| Density, g/cm3 (lb/in.3) | 7.9 (0.29) |
| Melting point, °C (°F) | 1400-1425 (2550-2600) |
| Specific heat capacity, J/kg·K (Btu/lb ·°F) | 500 (0.12) at 20 °C |
| Electrical resistivity, μΩ·m | 0.72 at 20 °C |
| Magnetic permeability | 1.02 (Approximate) |
| Elastic modulus, GPa (106 psi) | 193 (28) |
| Thermal conductivity, W/m·K (Btu/ft · h ·°F) | 16.1 (9.3) at 100 °C (212 °F) |
| 22.2 (12.8) at 500 °C (932 °F) |
| Coefficient of thermal expansion, 10-6/K (μin./in. ·°F) | 16.6 (9.2) at 0-100 °C (32-212 °F) |
| 17.2 (9.6) at 0-315 °C (32-600 °F) |
| 18.6 (10.3) at 0-538 °C (32-1000 °F) |
Mechanical Properties
AISI 321 stainless steel mechanical properties are listed in the
following tables.
| SS 321 Mechanical Properties |
| ASTM | AISI Type (UNS) | Conditions | Tensile Strength, MPa (ksi), ≥ | 0.2% Yield Strength, MPa (ksi), ≥ | Elongation in 50 mm (2 in.), %, ≥ | Reduction of Area, %, ≥ | Brinell Hardness (HBW), ≤ | Rockwell Hardness (HRBW), ≤ | Product forms |
| ASTM A276/A276M | 321 (UNS S32100) | Annealed, Hot finished | 515 (75) | 205 (30) | 40 | 50 | – | – | Bars and Shapes |
| Annealed, Cold finished, Dia ≤ 12.7 mm (0.5 in.) | 620 (90) | 310 (45) | 30 | 40 | – | – |
| Annealed, Cold finished, Dia > 12.7 mm (0.5 in.) | 515 (75) | 205 (30) | 30 | 40 | – | – |
| ASTM A580/A580M | Annealed | 520 (75) | 210 (30) | 35 | 50 | | | Wire |
| Cold finished | 620 (90) | 310 (45) | 30 | 40 | – | – |
| ASTM A473/A473M | Annealed, Sections ≤ 5 in. (127 mm) | 515 (75) | 205 (30) | 40 | 50 | – | – | Forgings |
| Annealed, Sections > 5 in. (127 mm) | 70 (485) |
| ASTM A240/A240M | 321, 321H (UNS S32109) | – | 515 (75) | 205 (30) | 40 | – | 201 | 92 | Plate, Sheet, and Strip |
Products partially or completely constructed of 321 include:
- Aircraft exhaust stacks
- Aircraft piston engine manifolds
- Chemical processing equipment
- Compensators and expansion bellows
- Expansion joints
- Furnace components
- High temperature chemical process equipment
- Jet engine parts
- Manifolds
- Refinery equipment
- Superheater and afterburner parts
- Thermal oxidizers
- Welded equipment
