Stainless Steel 321H Stabilize Annealed
Heat-treated state
AISI/SAE 321H · UNS S32109 · ASTM A240 TP321H
Extra stabilizing soak that converts residual carbon to TiC; specified for refinery service to resist polythionic-acid and intergranular stress-corrosion cracking.
Values for the Stabilize Annealed condition
Other 321H tempers and conditions
321H is listed in 6 conditions; see the grade overview at 321H.
- Stabilize Annealed
- Hot Rolled Annealed
- Solution Annealed
- Annealed
- Cold Drawn
- 1/4 Hard
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stabilize AnnealedThis page 870–900 °C hold after solution anneal | Extra stabilizing soak that converts residual carbon to TiC; specified for refinery service to resist polythionic-acid and intergranular stress-corrosion cracking. | 235 | 575 | 42 | 160 HB | 2.4 % IACS |
Hot Rolled, Annealed and Pickled (HRAP plate / hot-finished bar) | Standard supply state for thick 321H plate and hot-finished bar for pressure vessels and structural high-temperature parts. | 235 | 560 | 45 | 165 HB | 2.4 % IACS |
Solution AnnealedDefault 1050–1100 °C, rapid cooled | Default mill condition for 321H plate, sheet, tube and pipe; maximum ductility and corrosion resistance, ASME-qualified for elevated-temperature service. | 240 | 585 | 45 | 160 HB | — |
mill-annealed sheet/strip and bar | Generic soft mill-annealed condition for cold-rolled sheet, strip and annealed bar; use when maximum formability is needed. | 250 | 600 | 45 | 165 HB | 2.4 % IACS |
cold-finished bar/wire (light cold work) | Cold-finished bar with higher strength, closer tolerance and better surface for machined fasteners and shafts; anneal or stabilize before long high-temperature exposure. | 415 | 690 | 30 | 200 HB | — |
Quarter hard | Lightly temper-rolled strip for springy clips, gaskets and expansion-joint bellows where extra yield strength is wanted at near-ambient temperature. | 530 | 790 | 15 | 25 HRC | 2.4 % IACS |
What is 321H Stabilize Annealed?
321H Stabilize Annealed is 321H heat treated to Stabilize Annealed — extra stabilizing soak that converts residual carbon to TiC; specified for refinery service to resist polythionic-acid and intergranular stress-corrosion cracking. 321H Stabilize Annealed has a yield strength of 235 MPa (34.1 ksi) and a tensile strength of 575 MPa (83.4 ksi) — weaker than 98% of stainless steel grades. Elongation at break is 42% and the elastic modulus is 193 GPa (28 Msi). 321H Stabilize Annealed has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,398°C (2,548 °F). Solution Annealed is the default condition FabDigit quotes; Stabilize Annealed is available on request or by drawing note.
Advantages
- Forms and bends easily — 76/100, better than 88% of stainless steel grades
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% of stainless steel grades
- High service temperature — 900°C (1,652 °F), better than 85% of stainless steel grades
- Readily welded — 84/100, better than 85% of stainless steel grades
Limitations
- Low strength — 235 MPa (34.1 ksi), worse than 98% 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 Stabilize Annealed properties
Typical room-temperature values for 321H Stabilize Annealed; 22 are specific to this condition. Other listed values are 321H reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
321H Stabilize Annealed has a density of 7.9 g/cm³ (0.285 lb/in³), heavier than 68% of stainless steel grades. It melts at 1,398°C (2,548 °F).
Mechanical16
321H Stabilize Annealed has a yield strength of 235 MPa (34.1 ksi) and a tensile strength of 575 MPa (83.4 ksi) — weaker than 98% of stainless steel grades. Elongation at break is 42% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
321H Stabilize 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 Stabilize Annealed conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 63% of stainless steel grades.
Sustainability4
Producing a kilogram of 321H Stabilize 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 Stabilize Annealed's machinability is fair (40/100, better than 72% of stainless steel grades); weldability very good (84/100); formability very good (76/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 321H Stabilize 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 Stabilize Annealed — frequently asked
What is 321H Stabilize Annealed used for?
321H Stabilize 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 Stabilize Annealed?
321H Stabilize Annealed has a typical yield strength of 235 MPa (34.1 ksi) and a tensile strength of 575 MPa (83.4 ksi) — weaker than 98% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 321H Stabilize Annealed easy to machine?
Not especially — machinability is rated fair (40/100, better than 72% 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 Stabilize Annealed be welded?
Yes — weldability is rated very good (84/100). 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 Stabilize 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 Stabilize 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 Stabilize Annealed?
321H Stabilize 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 Stabilize Annealed?
Yes — 321H Stabilize Annealed is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. 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.