Stainless Steel 347 · heat-treated state · default condition
Stainless Steel 347 Solution Annealed
Properties of the Solution Annealed condition, compared with the other 347 tempers.
Default stock condition for plate, sheet, bar, pipe and tube — maximum ductility and corrosion resistance.
What is 347 Solution Annealed?
347 Solution Annealed is 347 heat treated to Solution Annealed — default stock condition for plate, sheet, bar, pipe and tube — maximum ductility and corrosion resistance. 347 Solution Annealed has a yield strength of 245 MPa (35.5 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 94% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 193 GPa (28 Msi). 347 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
- Readily welded — 90/100, better than 95% of stainless steel grades
- Forms and bends easily — 80/100, better than 93% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 84% of stainless steel grades
- High service temperature — 870°C (1,598 °F), better than 82% of stainless steel grades
Limitations
- Low strength — 245 MPa (35.5 ksi), worse than 94% of stainless steel grades
- High embodied carbon — 5.5 kg CO₂/kg, worse than 77% of stainless steel grades
347 Solution Annealed properties
Typical room-temperature values for 347 Solution Annealed — 11 properties are specific to this condition; the rest are grade-level values shared by every 347 temper. Each bar shows where the value sits among the stainless steel grades in FabDigit's library — further right is higher.
Physical3
347 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).
Mechanical16
347 Solution Annealed has a yield strength of 245 MPa (35.5 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 94% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 193 GPa (28 Msi).
Thermal6
347 Solution Annealed is rated for continuous service to 870°C (1,598 °F). It conducts heat at 16 W/m·K (9.24 BTU/hr·ft·°F), better than 58% of stainless steel grades. Thermal expansion is 16.6 µm/m·K (9.22 µin/in·°F).
Electrical3
347 Solution Annealed conducts electricity at 2.4 % IACS, better than 67% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (66/100), better than 58% of stainless steel grades.
Sustainability4
Producing a kilogram of 347 Solution Annealed takes about 57 MJ of energy and emits 5.5 kg of CO₂ — more than 61% of stainless steel grades. Typical recycled content is 60%.
Manufacturability7
347 Solution Annealed's machinability is fair (38/100, better than 63% of stainless steel grades); weldability excellent (90/100); formability very good (80/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 347 tempers and conditions
347 is also supplied in 9 other conditions. The full side-by-side table is on the 347 overview.
- Solution AnnealedDefaultDefault stock condition for plate, sheet, bar, pipe and tube — maximum ductility and corrosion resistance.245 MPa yield · 160 HB
- Cold DrawnHigher strength, tighter tolerance and better surface for screw-machine parts and fasteners.550 MPa yield · 240 HB
Working with 347 Solution Annealed
Is 347 easy to machine?
Gummy and work-hardening with abrasive NbC particles — use rigid setups, positive-rake coated carbide, heavy constant feed, no dwelling, and flood coolant; ~40 % of 1212 speeds.
Can 347 be welded?
Excellent by GTAW/GMAW/SMAW with ER347/E347 filler; the Nb stabilization means no post-weld solution anneal is needed, but keep heat input low and interpass < 150 °C to limit distortion and hot-cracking risk.
Can 347 be formed, bent or molded?
Cold forms and deep draws well but work-hardens faster than 304 — allow extra power, generous radii and intermediate anneals at 1010–1120 °C followed by rapid cooling.
What surface finishes work on 347?
Passivate per ASTM A967 or electropolish after machining; not anodizable — bead blast, No.4 brush or mirror polish are the usual finishes, and pickling paste removes weld heat tint.
347 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 |
|---|---|---|
| C347H: 0.04–0.10 | ≤ 0.08 | 0.05 |
| Mn | ≤ 2 | 1.5 |
| Si | ≤ 0.75 | 0.5 |
| P | ≤ 0.05 | — |
| S | ≤ 0.03 | — |
| Cr | 17 – 19 | 18 |
| Ni | 9 – 13 | 11 |
| NbNb(+Ta) ≥ 10×C; EN 1.4550 requires Nb ≥ 10×C, max 1.00 | ≤ 1 | 0.6 |
| Talimited only in nuclear/Co-controlled orders | ≤ 0.1 | — |
| NEN 1.4550 limit | ≤ 0.1 | 0.04 |
| Fe | balance | — |
347 Solution Annealed — frequently asked
What is 347 Solution Annealed used for?
347 Solution Annealed is typically used for boiler and superheater piping, refinery and petrochemical process piping, exhaust systems and expansion bellows, welded pressure vessels for hot service, heat exchanger tubes and tubesheets and aircraft collector rings and ducting. In short: niobium-stabilized austenitic stainless.
What is the yield strength of 347 Solution Annealed?
347 Solution Annealed has a typical yield strength of 245 MPa (35.5 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 94% of stainless steel grades. Strength varies by condition: see the 10 listed tempers.
Is 347 Solution 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 NbC particles — use rigid setups, positive-rake coated carbide, heavy constant feed, no dwelling, and flood coolant; ~40 % of 1212 speeds.
Can 347 Solution Annealed be welded?
Yes — weldability is rated excellent (90/100). Excellent by GTAW/GMAW/SMAW with ER347/E347 filler; the Nb stabilization means no post-weld solution anneal is needed, but keep heat input low and interpass < 150 °C to limit distortion and hot-cracking risk.
What surface finishes work on 347 Solution Annealed?
Passivate per ASTM A967 or electropolish after machining; not anodizable — bead blast, No.4 brush or mirror polish are the usual finishes, and pickling paste removes weld heat tint.
Can 347 Solution Annealed be formed, bent or molded?
Cold forms and deep draws well but work-hardens faster than 304 — allow extra power, generous radii and intermediate anneals at 1010–1120 °C followed by rapid cooling.
What is the maximum service temperature of 347 Solution Annealed?
347 Solution 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.
What is the difference between 347 Solution Annealed and 347H?
Solution Annealed is the default condition — default stock condition for plate, sheet, bar, pipe and tube — maximum ductility and corrosion resistance. 347H: pick for ASME code creep service above 540 °C — higher allowable stresses and better rupture life than plain 347. Yield strength is 245 MPa in Solution Annealed versus 240 MPa in 347H.
Can FabDigit make parts in 347 Solution Annealed?
Yes — 347 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 — Cr and Cr-Ni Stainless Plate, Sheet and Strip — ASTM International (2023)
- ASTM A276/A276M — Stainless Steel Bars and Shapes — ASTM International (2023)
- EN 10088-2 — Stainless steels, technical delivery conditions for sheet/plate (1.4550) — CEN (2014)
- GB/T 1220 / GB/T 4237 (0Cr18Ni11Nb) — SAC (2015)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
- 347/347H Stainless Steel Product Data Sheet — AK Steel / Cleveland-Cliffs (2021)
- Outokumpu Steel Grade 4550 datasheet — Outokumpu (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.