Stainless Steel 321H · heat-treated state · default condition
Stainless Steel 321H Solution Annealed
Properties of the Solution Annealed condition, compared with the other 321H tempers.
Default mill condition for 321H plate, sheet, tube and pipe; maximum ductility and corrosion resistance, ASME-qualified for elevated-temperature service.
What is 321H Solution Annealed?
321H Solution Annealed is 321H heat treated to Solution Annealed — default mill condition for 321H plate, sheet, tube and pipe; maximum ductility and corrosion resistance, ASME-qualified for elevated-temperature service. 321H Solution Annealed has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 96% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 193 GPa (28 Msi). 321H Solution Annealed has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 67% of stainless steel grades. It melts at 1,398°C (2,548 °F).
Advantages
- Forms and bends easily — 78/100, better than 90% of stainless steel grades
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 84% of stainless steel grades
- High service temperature — 900°C (1,652 °F), better than 84% of stainless steel grades
- Readily welded — 82/100, better than 83% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
Limitations
- Low strength — 240 MPa (34.8 ksi), worse than 96% of stainless steel grades
- Hard to polish — 60/100, worse than 80% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
321H Solution Annealed properties
Typical room-temperature values for 321H Solution Annealed — 16 properties are specific to this condition; the rest are grade-level values shared by every 321H temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
321H Solution Annealed has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 67% of stainless steel grades. It melts at 1,398°C (2,548 °F).
Mechanical16
321H Solution Annealed has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 96% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
321H Solution Annealed is rated for continuous service to 900°C (1,652 °F). It conducts heat at 16.1 W/m·K (9.3 BTU/hr·ft·°F), better than 61% of stainless steel grades. Thermal expansion is 16.6 µm/m·K (9.22 µin/in·°F).
Electrical3
321H Solution Annealed conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (64/100), better than 53% of stainless steel grades.
Sustainability4
Producing a kilogram of 321H Solution Annealed takes about 56 MJ of energy and emits 5.5 kg of CO₂ — more than 59% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
321H Solution Annealed's machinability is fair (40/100, better than 73% of stainless steel grades); weldability very good (82/100); formability very good (78/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 321H tempers and conditions
321H is also supplied in 5 other conditions. The full side-by-side table is on the 321H overview.
- Solution AnnealedDefaultDefault mill condition for 321H plate, sheet, tube and pipe; maximum ductility and corrosion resistance, ASME-qualified for elevated-temperature service.240 MPa yield · 160 HB
- 1/4 HardLightly temper-rolled strip for springy clips, gaskets and expansion-joint bellows where extra yield strength is wanted at near-ambient temperature.530 MPa yield · 25 HRC
- Cold DrawnCold-finished bar with higher strength, closer tolerance and better surface for machined fasteners and shafts; anneal or stabilize before long high-temperature exposure.415 MPa yield · 200 HB
- AnnealedGeneric soft mill-annealed condition for cold-rolled sheet, strip and annealed bar; use when maximum formability is needed.250 MPa yield · 165 HB
- Hot Rolled AnnealedStandard supply state for thick 321H plate and hot-finished bar for pressure vessels and structural high-temperature parts.235 MPa yield · 165 HB
Working with 321H Solution Annealed
Is 321H easy to machine?
Treat as a gummy work-hardening austenitic: rigid setup, positive-rake sharp carbide, 0.15–0.35 mm/rev feed, 60–110 m/min, flood coolant, never dwell — TiC particles accelerate tool wear versus 304.
Can 321H be welded?
Excellent by GTAW/GMAW/SMAW without post-weld anneal; use ER347/E347 or ER321 filler (Nb-stabilized filler avoids Ti burn-off), keep heat input moderate and interpass low, no preheat, avoid carbon pickup and use back purge on tube.
Can 321H be formed, bent or molded?
Cold forms readily but work-hardens faster than 304 — allow ~15 % more press force, generous bend radii and interstage anneal at 1050–1100 °C for severe draws; hot work 1150–1200 °C, finish above 900 °C then solution anneal.
What surface finishes work on 321H?
Not anodizable: pickle in HNO₃/HF and passivate in nitric or citric acid; Ti carbonitride stringers can leave streaks in mirror polish, so electropolishing or bead blast is preferred for high-purity or decorative surfaces.
321H chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Craised carbon vs. 321 for creep strength | 0.04 – 0.1 | 0.06 |
| Cr | 17 – 19 | 18 |
| Ni | 9 – 12 | 10.5 |
| Tispec minimum = 4×(C+N); 0.24 shown as practical minimum | 0.24 – 0.7 | 0.4 |
| Mn | ≤ 2 | 1.2 |
| Si | ≤ 0.75 | 0.5 |
| N | ≤ 0.1 | 0.02 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance | — |
321H Solution Annealed — frequently asked
What is 321H Solution Annealed used for?
321H Solution Annealed is typically used for aircraft and engine exhaust manifolds, high-temperature pressure pipework, boiler and superheater components, expansion joints and bellows, refinery heater tubes and headers and furnace and heat-treatment fixtures. In short: high-temp titanium-stabilized stainless.
What is the yield strength of 321H Solution Annealed?
321H Solution Annealed has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 585 MPa (84.8 ksi) — weaker than 96% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 321H Solution Annealed easy to machine?
Not especially — machinability is rated fair (40/100, better than 73% of stainless steel grades). Treat as a gummy work-hardening austenitic: rigid setup, positive-rake sharp carbide, 0.15–0.35 mm/rev feed, 60–110 m/min, flood coolant, never dwell — TiC particles accelerate tool wear versus 304.
Can 321H Solution Annealed be welded?
Yes — weldability is rated very good (82/100). Excellent by GTAW/GMAW/SMAW without post-weld anneal; use ER347/E347 or ER321 filler (Nb-stabilized filler avoids Ti burn-off), keep heat input moderate and interpass low, no preheat, avoid carbon pickup and use back purge on tube.
What surface finishes work on 321H Solution Annealed?
Not anodizable: pickle in HNO₃/HF and passivate in nitric or citric acid; Ti carbonitride stringers can leave streaks in mirror polish, so electropolishing or bead blast is preferred for high-purity or decorative surfaces.
Can 321H Solution Annealed be formed, bent or molded?
Cold forms readily but work-hardens faster than 304 — allow ~15 % more press force, generous bend radii and interstage anneal at 1050–1100 °C for severe draws; hot work 1150–1200 °C, finish above 900 °C then solution anneal.
What is the maximum service temperature of 321H Solution Annealed?
321H Solution Annealed is rated for continuous use to about 900°C (1,652 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 321H Solution Annealed?
Yes — 321H Solution Annealed is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip — ASTM International (2023)
- ASTM A213/A213M — Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes — ASTM International (2022)
- ASTM A312 / A276 — Austenitic Stainless Steel Pipe and Bars — ASTM International (2022)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- GB/T 24511 / GB/T 1220 — (06Cr18Ni11Ti) — SAC (2017)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Outokumpu 4878 / 321H stainless steel data sheet — Outokumpu (2023)
- Sandvik 8R30 / TP321H tube data sheet — Alleima (Sandvik Materials Technology) (2022)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.