Stainless Steel 348H Stabilize-Annealed
Heat-treated state
AISI/SAE 348H · UNS S34809 · ASTM A240 TP348H
Choose when maximum immunity to intergranular and knife-line attack is needed after welding or for severe nitric-acid/high-temperature service.
Values for the Stabilize-Annealed condition
Other 348H tempers and conditions
348H is listed in 6 conditions; see the grade overview at 348H.
- Hot Finished
- Stabilize-Annealed
- Annealed
- Cold Drawn
- 1/4 Hard
- 1/2 Hard
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot finished / hot rolled and annealed bar and plate | Economical heavy plate and large-section bar for pressure vessel and header parts where surface finish is not critical. | 260 | 600 | 48 | 165 HB | 2.4 % IACS |
Stabilize-AnnealedThis page ~900 °C hold after solution anneal | Choose when maximum immunity to intergranular and knife-line attack is needed after welding or for severe nitric-acid/high-temperature service. | 270 | 610 | 48 | 163 HB | 2.4 % IACS |
AnnealedDefault solution annealed (ASTM A240/A213/A479 condition A) | Standard supply condition for plate, sheet, pipe and tube used in high-temperature and nuclear pressure service. | 275 | 620 | 50 | 160 HB | — |
Cold drawn / cold finished bar and tube (lightly cold worked) | Pick for close tolerances, better surface finish and higher yield strength in small-diameter bar, tube and fasteners. | 480 | 725 | 25 | 18 HRC | 2.4 % IACS |
Quarter hard | Use for stiffer springs, clips and formed strip parts where some cold formability must remain. | 515 | 860 | 12 | 25 HRC | 2.4 % IACS |
Half hard | Highest strength normally stocked in strip form; only mild bending is possible. | 760 | 1,035 | 8 | 32 HRC | 2.4 % IACS |
What is 348H Stabilize-Annealed?
348H Stabilize-Annealed is 348H heat treated to Stabilize-Annealed — choose when maximum immunity to intergranular and knife-line attack is needed after welding or for severe nitric-acid/high-temperature service. 348H Stabilize-Annealed has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 610 MPa (88.5 ksi) — weaker than 79% of stainless steel grades. Elongation at break is 48% and the elastic modulus is 195 GPa (28.3 Msi). 348H Stabilize-Annealed has a density of 7.96 g/cm³ (0.288 lb/in³), heavier than 83% of stainless steel grades. It melts at 1,400°C (2,552 °F). Annealed is the default condition FabDigit quotes; Stabilize-Annealed is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 48%, better than 85% of stainless steel grades
- Readily welded — 82/100, better than 84% of stainless steel grades
- High service temperature — 870°C (1,598 °F), better than 83% of stainless steel grades
- Tough — resists crack growth — 195 MPa·√m (177.5 ksi·√in), better than 77% of stainless steel grades
- Forms and bends easily — 68/100, better than 75% of stainless steel grades
Limitations
- Low strength — 270 MPa (39.2 ksi), worse than 79% of stainless steel grades
348H Stabilize-Annealed properties
Typical room-temperature values for 348H Stabilize-Annealed; 22 are specific to this condition. Other listed values are 348H reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
348H Stabilize-Annealed has a density of 7.96 g/cm³ (0.288 lb/in³), heavier than 83% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
348H Stabilize-Annealed has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 610 MPa (88.5 ksi) — weaker than 79% of stainless steel grades. Elongation at break is 48% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
348H Stabilize-Annealed is rated for continuous service to 870°C (1,598 °F). It conducts heat at 16.3 W/m·K (9.42 BTU/hr·ft·°F), better than 68% of stainless steel grades. Thermal expansion is 16.6 µm/m·K (9.22 µin/in·°F).
Electrical3
348H Stabilize-Annealed conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), worse than 62% of stainless steel grades.
Sustainability4
Producing a kilogram of 348H Stabilize-Annealed takes about 78 MJ of energy and emits 5 kg of CO₂ — more than 87% of stainless steel grades. Typical recycled content is 55%.
Manufacturability7
348H Stabilize-Annealed's machinability is fair (38/100, better than 63% of stainless steel grades); weldability very good (82/100); formability good (68/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 348H Stabilize-Annealed
Is 348H easy to machine?
Gummy and work-hardening with abrasive Nb/Ta carbides — use rigid setups, sharp positive-rake carbide, ~30–60 m/min, heavy positive feed and flood coolant; avoid dwelling to prevent glazing.
Can 348H be welded?
Readily welded by GTAW/GMAW/SMAW with ER347/E347 filler; no post-weld anneal is normally required, but minimise heat input and consider a ~900 °C stabilising anneal where knife-line attack or hot nitric service is a concern.
Can 348H be formed, bent or molded?
Cold forms well in the annealed condition though springback and work hardening exceed 304; hot work at 1150–1200 °C and always solution anneal at 1040–1100 °C followed by rapid cooling.
What surface finishes work on 348H?
Cannot be anodised — pickle and passivate per ASTM A380/A967, electropolish for nuclear cleanliness; takes a good mechanical polish, with carbide stringers occasionally showing as faint comet tails.
348H 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 for creep strength (the 'H' grade) | 0.04 – 0.1 | 0.07 |
| Cr | 17 – 19 | 18 |
| Ni | 9 – 13 | 11 |
| NbNb (+Ta) ≥ 8 × C; Nb+Ta reported together | 0.56 – 1 | 0.75 |
| Tarestricted for nuclear (low neutron capture) | ≤ 0.1 | 0.05 |
| Corestricted for nuclear service | ≤ 0.2 | 0.1 |
| Mn | ≤ 2 | 1.5 |
| Si1.00 max in some product specs | ≤ 0.75 | 0.5 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Fe | balance | — |
348H Stabilize-Annealed — frequently asked
What is 348H Stabilize-Annealed used for?
348H Stabilize-Annealed is typically used for nuclear reactor piping, high-temperature nuclear components, reactor internal support structures, superheater and reheater tubing, high-temperature steam headers and spools and forged valve and fitting bodies for hot service. In short: creep-resistant 348 variant; nuclear-service stabilised grade; 815 °C service limit.
What is the yield strength of 348H Stabilize-Annealed?
348H Stabilize-Annealed has a typical yield strength of 270 MPa (39.2 ksi) and a tensile strength of 610 MPa (88.5 ksi) — weaker than 79% of stainless steel grades. Strength varies by condition: see the 6 listed tempers.
Is 348H Stabilize-Annealed easy to machine?
Not especially — machinability is rated fair (38/100, better than 63% of stainless steel grades). Gummy and work-hardening with abrasive Nb/Ta carbides — use rigid setups, sharp positive-rake carbide, ~30–60 m/min, heavy positive feed and flood coolant; avoid dwelling to prevent glazing.
Can 348H Stabilize-Annealed be welded?
Yes — weldability is rated very good (82/100). Readily welded by GTAW/GMAW/SMAW with ER347/E347 filler; no post-weld anneal is normally required, but minimise heat input and consider a ~900 °C stabilising anneal where knife-line attack or hot nitric service is a concern.
What surface finishes work on 348H Stabilize-Annealed?
Cannot be anodised — pickle and passivate per ASTM A380/A967, electropolish for nuclear cleanliness; takes a good mechanical polish, with carbide stringers occasionally showing as faint comet tails.
Can 348H Stabilize-Annealed be formed, bent or molded?
Cold forms well in the annealed condition though springback and work hardening exceed 304; hot work at 1150–1200 °C and always solution anneal at 1040–1100 °C followed by rapid cooling.
What is the maximum service temperature of 348H Stabilize-Annealed?
348H Stabilize-Annealed is rated for continuous use to about 870°C (1,598 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip (TP348H, S34809) — ASTM International (2023)
- ASTM A213/A213M — Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater and Heat-Exchanger Tubes — ASTM International (2022)
- ASTM A479/A479M — Stainless Steel Bars and Shapes for Boilers and Other Pressure Vessels — ASTM International (2021)
- ASME BPVC Section II Part D — Properties (Metric), austenitic stainless allowable stresses — ASME (2023)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ATI 347 / ATI 348 Technical Data Sheet — ATI Specialty Materials (2020)
- Machinery's Handbook — machinability ratings for stainless steels — Industrial Press (2020)
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.