Heat Resistant SS · Austenitic
Stainless Steel 321
Stainless Steel 321 is a heat resistant stainless steel — creep resistant high-temp. Typical values: 205 MPa yield, 8 g/cm³, rated to 800 °C. Available for CNC machining, Sheet metal at FabDigit.
Properties
Typical room-temperature values in the Solution Annealed condition. Metric first, imperial in gray. The bars show where 321 sits against the other 87 stainless steel grades in the catalog.
Datasheet
| Yield strength | 205 MPa30 ksi |
|---|---|
| Tensile strength | 515 MPa75 ksi |
| Hardness | 150 HB |
| Density | 8 g/cm³0.289 lb/in³ |
| Specific strength (yield ÷ density) | 26 |
| Min service temp | -200 °C-328 °F |
| Max service temp | 800 °C1,472 °F |
| Electrical conductivity | 2.4 % IACS1.4 MS/m |
| Machinability | Fair40 / 100 |
| Weldability | Excellent95 / 100 |
| Formability | Very good70 / 100 |
| ISO 513 machining group | M |
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Against other stainless steel grades
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. 321 is highlighted; hover a dot for its name, or open the interactive family chart.
Manufacturability
The process limits FabDigit's quote engine applies to 321. Design inside these and the part quotes instantly; outside them it routes to an engineer.
CNC machining
| Machinability | Fair40 / 100 |
|---|---|
| ISO material group | M.1 |
| Cutting speed (rough / finish) | 150 / 180 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1.5 mm |
| Drill depth limit | 4× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better70 / 100 |
|---|---|
| Weldability | Better95 / 100 |
| Bendable | Yes |
| Minimum bend radius | 1× thickness |
| Spring-back | High |
| Welding processes | TIG, MIG, SPOT, SEAM, LASER |
Conditions and tempers
How 321 is supplied and what each state is for. The default is what FabDigit quotes unless your drawing says otherwise.
| Condition | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Solution AnnealedDefault Heat Treat State | Best corrosion resistance — food, chemical, marine hardware | — | — | — | — |
Annealed Temper | Softest supply state — for forming, or when you heat-treat after machining | — | — | — | — |
Heat treatment and post-processing
Operations FabDigit's suppliers routinely run on 321, ranked by how often they make sense for this grade.
Heat treatment
| Solution Anneal | Dissolve carbides; reset austenite (stainless) |
|---|---|
| Stress Relief | Reduce residual stress without changing structure |
| Quench & Temper | Achieve target hardness with controlled toughness28–55 HRC |
Post-processing
| Manual Deburr | Deburrstandard |
|---|---|
| Passivate (Citric) | Passivation |
| Edge Break (0.5mm) | Deburr |
| Passivate (Nitric / AMS 2700) | Passivation |
| Electropolish | Polish |
| Glass Bead Blast | Blast |
| Laser Mark | Marking |
| CMM Inspection | Inspection |
| FAI Report | Inspection |
| Individual Bag | Packaging |
Surface finishes for 321
Coatings and treatments compatible with stainless steel on the processes 321 runs on. Pick them in the quote configurator or call them out on the drawing.
Passivation
- Electropolishing
- Passivation (Stainless Steel)
- Pickling
Plating
- Chrome Plating
- Electroless Nickel (EN)
- Gold Plating
- Hard Chrome Plating
- Nickel Plating
- Silver Plating
PVD Coating
- AlCrN
- AlTiN
- CrN
- DLC
- MoS2
- TiAlN
- TiB2
- TiCN
- TiN
- WC/C
- ZrN
Organic Coating
- Cerakote
- Epoxy Coating
- Painting
- Powder Coating
- PTFE Coating
CVD Coating
- CVD Al2O3
- CVD TiCN
- CVD TiN
- Multilayer CVD
Marking / Decoration
- Chemical Etching
- Dot Peen Marking
- Electro-chemical Etching
- Embossing / Debossing
- Ink Stamping
- Laser Marking
- Mechanical Engraving
- Steel Stamping
- Vibro Engraving / Scribing
Black / Phosphate
- Black Oxide
Thermal Spray
- HVOF Coating
- Plasma Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel 321 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- S32100
- EN / DIN / Werkstoff-Nr.
- 1.4541X6CrNiTi18-10
- JIS
- SUS321
Stock forms
Raw-material forms FabDigit sources 321 in.
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.