Stainless Steel 347H · heat-treated state · default condition
Stainless Steel 347H Solution Annealed
Properties of the Solution Annealed condition, compared with the other 347H tempers.
Standard as-supplied condition for plate, tube and pipe; maximum ductility and corrosion resistance, ASME-code creep properties.
What is 347H Solution Annealed?
347H Solution Annealed is 347H heat treated to Solution Annealed — standard as-supplied condition for plate, tube and pipe; maximum ductility and corrosion resistance, ASME-code creep properties. 347H Solution Annealed has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 195 GPa (28.3 Msi). 347H Solution Annealed has a density of 7.96 g/cm³ (0.288 lb/in³), heavier than 82% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 84% of stainless steel grades
- High service temperature — 815°C (1,499 °F), better than 77% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
Limitations
- Low strength — 275 MPa (39.9 ksi), worse than 77% of stainless steel grades
347H Solution Annealed properties
Typical room-temperature values for 347H Solution Annealed — 13 properties are specific to this condition; the rest are grade-level values shared by every 347H temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
347H Solution Annealed has a density of 7.96 g/cm³ (0.288 lb/in³), heavier than 82% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
347H Solution Annealed has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 77% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 195 GPa (28.3 Msi).
Thermal6
347H Solution Annealed is rated for continuous service to 815°C (1,499 °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
347H Solution Annealed conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (57/100), worse than 66% of stainless steel grades.
Sustainability4
Producing a kilogram of 347H Solution Annealed takes about 60 MJ of energy and emits 5.3 kg of CO₂ — more than 70% of stainless steel grades. Typical recycled content is 60%.
Manufacturability8
347H Solution Annealed's machinability is fair (35/100, better than 51% of stainless steel grades); weldability very good (78/100); formability good (68/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 347H tempers and conditions
347H is also supplied in 4 other conditions. The full side-by-side table is on the 347H overview.
- Solution AnnealedDefaultStandard as-supplied condition for plate, tube and pipe; maximum ductility and corrosion resistance, ASME-code creep properties.275 MPa yield · 160 HB
- Cold DrawnChoose for close-tolerance small-diameter bar, higher yield strength and better surface for machined fittings and studs.520 MPa yield · 225 HB
- AnnealedBar, forgings and fittings delivered fully annealed when softness and machining/forming ease matter more than strength.255 MPa yield · 150 HB
Working with 347H Solution Annealed
Is 347H easy to machine?
Machine like 321/304 but expect abrasive NbC: rigid setup, sharp coated carbide, 25–60 m/min, heavy positive feed to cut through the work-hardened skin, flood coolant, no dwelling.
Can 347H be welded?
Readily welded by GTAW/GMAW/SMAW with ER347/E347 filler (ER16-8-2 for thick multipass creep service); low heat input, no preheat, keep interpass low to limit hot cracking, and add a 900 °C stabilizing anneal where knife-line attack or polythionic SCC is a risk.
Can 347H be formed, bent or molded?
Cold forms well but work-hardens fast — allow ~50 % more press force than mild steel, generous bend radii, and interstage annealing; hot work at 1150–1200 °C and always solution anneal afterwards.
What surface finishes work on 347H?
Pickle and passivate (ASTM A380/A967) or electropolish after fabrication to restore the chromium oxide film; takes a good mechanical or mirror polish, never anodized, and can be Ni-brazed in vacuum or dry hydrogen.
347H 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 |
|---|---|---|
| Cdeliberately high for creep strength (H grade) | 0.04 – 0.1 | 0.06 |
| Si1.00 max in some product standards | ≤ 0.75 | 0.5 |
| Mn | ≤ 2 | 1.5 |
| P | ≤ 0.05 | 0.03 |
| S | ≤ 0.03 | 0.01 |
| Cr | 17 – 19 | 18 |
| Ni | 9 – 13 | 11 |
| NbNb(+Ta) ≥ 8 × C per ASTM A240/A213; min shown for C = 0.04 | 0.32 – 1 | 0.6 |
| Fe | balance | — |
347H Solution Annealed — frequently asked
What is 347H Solution Annealed used for?
347H Solution Annealed is typically used for boiler and superheater tubing, refinery heater and reformer piping, power plant steam headers, high-temperature pressure vessels, petrochemical reactor internals and expansion joints and bellows. In short: high-temp niobium-stabilized stainless.
What is the yield strength of 347H Solution Annealed?
347H Solution Annealed has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 77% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is 347H Solution Annealed easy to machine?
Not especially — machinability is rated fair (35/100, better than 51% of stainless steel grades). Machine like 321/304 but expect abrasive NbC: rigid setup, sharp coated carbide, 25–60 m/min, heavy positive feed to cut through the work-hardened skin, flood coolant, no dwelling.
Can 347H Solution Annealed be welded?
Yes — weldability is rated very good (78/100). Readily welded by GTAW/GMAW/SMAW with ER347/E347 filler (ER16-8-2 for thick multipass creep service); low heat input, no preheat, keep interpass low to limit hot cracking, and add a 900 °C stabilizing anneal where knife-line attack or polythionic SCC is a risk.
What surface finishes work on 347H Solution Annealed?
Pickle and passivate (ASTM A380/A967) or electropolish after fabrication to restore the chromium oxide film; takes a good mechanical or mirror polish, never anodized, and can be Ni-brazed in vacuum or dry hydrogen.
Can 347H Solution Annealed be formed, bent or molded?
Cold forms well but work-hardens fast — allow ~50 % more press force than mild steel, generous bend radii, and interstage annealing; hot work at 1150–1200 °C and always solution anneal afterwards.
What is the maximum service temperature of 347H Solution Annealed?
347H Solution Annealed is rated for continuous use to about 815°C (1,499 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 347H Solution Annealed?
Yes — 347H 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/A312M and A479/A484 (S34709 pipe and bar) — ASTM International (2022)
- ASME BPVC Section II Part D — allowable stresses for SA-213 TP347H — ASME (2023)
- GB/T 1220 / GB/T 24593 (0Cr18Ni11Nb, 07Cr18Ni11Nb) — SAC (2018)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Sandvik / Alleima 347H and Outokumpu 4550 datasheets — Alleima, Outokumpu (2023)
- (SMM / Mysteel / 1688 ) (2025)
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.