Stainless Steel N08366 1/4H
Supply condition
UNS N08366 · ASTM B676/B677
1/4H = quarter hard
Use for springy strip, gaskets and diaphragms where higher yield strength is needed and forming is minimal.
Values for the 1/4H condition
Other N08366 tempers and conditions
N08366 is listed in 4 conditions; see the grade overview at N08366.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedDefault solution annealed and water quenched (plate/sheet/tube) | Standard stocked condition for plate, sheet, pipe and tube; maximum corrosion resistance and ductility. | 305 | 655 | 45 | 170 HB | — |
As-welded deposit | Reference condition for welded tube and fabrication; expect some Mo segregation unless overalloyed Ni-base filler is used. | 320 | 640 | 35 | 185 HB | 1.7 % IACS |
Cold drawn | Choose for bar and fastener stock needing better straightness, surface finish and higher yield strength. | 480 | 760 | 30 | 19 HRC | 1.7 % IACS |
1/4HThis page Quarter hard | Use for springy strip, gaskets and diaphragms where higher yield strength is needed and forming is minimal. | 620 | 860 | 20 | 25 HRC | 1.7 % IACS |
What is N08366 1/4H?
N08366 1/4H is N08366 supplied in the 1/4H condition — use for springy strip, gaskets and diaphragms where higher yield strength is needed and forming is minimal. N08366 1/4H has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 88% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 196 GPa (28.4 Msi). N08366 1/4H has a density of 8.08 g/cm³ (0.292 lb/in³), heavier than 99% of stainless steel grades. It melts at 1,320°C (2,408 °F). Annealed is the default condition FabDigit quotes; 1/4H is available on request or by drawing note.
Advantages
- High strength — 620 MPa (89.9 ksi), better than 88% of stainless steel grades
- Good corrosion resistance — 78/100, better than 84% of stainless steel grades
Limitations
- Difficult to machine — 20/100, worse than 98% of stainless steel grades
- Poor heat conductor — 11.5 W/m·K (6.64 BTU/hr·ft·°F), worse than 97% of stainless steel grades
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- High embodied carbon — 6.5 kg CO₂/kg, worse than 93% of stainless steel grades
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
N08366 1/4H properties
Typical room-temperature values for N08366 1/4H; 24 are specific to this condition. Other listed values are N08366 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
N08366 1/4H has a density of 8.08 g/cm³ (0.292 lb/in³), heavier than 99% of stainless steel grades. It melts at 1,320°C (2,408 °F).
Mechanical14
N08366 1/4H has a yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 88% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 196 GPa (28.4 Msi).
Thermal5
N08366 1/4H is rated for continuous service to 300°C (572 °F). It conducts heat at 11.5 W/m·K (6.64 BTU/hr·ft·°F), worse than 97% of stainless steel grades. Thermal expansion is 15.3 µm/m·K (8.5 µin/in·°F).
Electrical3
N08366 1/4H conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 84% of stainless steel grades.
Sustainability4
Producing a kilogram of N08366 1/4H takes about 80 MJ of energy and emits 6.5 kg of CO₂ — more than 89% of stainless steel grades. Typical recycled content is 45%.
Manufacturability7
N08366 1/4H's machinability is poor (20/100, worse than 98% of stainless steel grades); weldability good (60/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with N08366 1/4H
Is N08366 easy to machine?
Slow speeds, heavy positive-rake carbide tooling, rigid setups and flood coolant; it work-hardens strongly and must be cut, not rubbed (~25 % of 1212).
Can N08366 be welded?
GTAW/GMAW/SMAW with overalloyed Ni-base filler (ERNiCrMo-3/-4) to keep weld Mo up; no preheat, low heat input, interpass below ~150 °C, no post-weld heat treat needed for thin sections.
Can N08366 be formed, bent or molded?
Cold forms well but needs ~1.5–2× the press force of 304 with allowance for springback; hot work 1150–1200 °C followed by rapid cooling to avoid σ/χ phase.
What surface finishes work on N08366?
Pickle in HNO₃-HF and passivate after hot work or welding to restore the passive film; electropolish or mechanically polish for sanitary service — no anodizing.
N08366 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 |
|---|---|---|
| Cmax per ASTM B688 | ≤ 0.04 | 0.02 |
| Mn | ≤ 2 | 1 |
| P | ≤ 0.03 | 0.02 |
| S | ≤ 0.03 | 0.01 |
| Si | ≤ 1 | 0.5 |
| Cr | 20 – 22 | 21 |
| Ni | 23.5 – 25.5 | 24.5 |
| Mosource of pitting/crevice resistance | 6 – 7 | 6.5 |
| Cu | ≤ 0.75 | 0.2 |
| Feremainder, ~46 % | balance | — |
N08366 1/4H — frequently asked
What is N08366 1/4H used for?
N08366 1/4H is typically used for seawater piping, pulp and paper bleach equipment, flue-gas desulfurization components and chemical process tanks. In short: first-generation 6Mo superaustenitic; chloride pitting resistance; AL-6XN predecessor grade.
What is the yield strength of N08366 1/4H?
N08366 1/4H has a typical yield strength of 620 MPa (89.9 ksi) and a tensile strength of 860 MPa (125 ksi) — stronger than 88% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is N08366 1/4H easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% of stainless steel grades). Slow speeds, heavy positive-rake carbide tooling, rigid setups and flood coolant; it work-hardens strongly and must be cut, not rubbed (~25 % of 1212).
Can N08366 1/4H be welded?
Yes — weldability is rated good (60/100). GTAW/GMAW/SMAW with overalloyed Ni-base filler (ERNiCrMo-3/-4) to keep weld Mo up; no preheat, low heat input, interpass below ~150 °C, no post-weld heat treat needed for thin sections.
What surface finishes work on N08366 1/4H?
Pickle in HNO₃-HF and passivate after hot work or welding to restore the passive film; electropolish or mechanically polish for sanitary service — no anodizing.
Can N08366 1/4H be formed, bent or molded?
Cold forms well but needs ~1.5–2× the press force of 304 with allowance for springback; hot work 1150–1200 °C followed by rapid cooling to avoid σ/χ phase.
What is the maximum service temperature of N08366 1/4H?
N08366 1/4H is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between N08366 Annealed and N08366-CD?
Annealed is the default condition — standard stocked condition for plate, sheet, pipe and tube; maximum corrosion resistance and ductility. CD: choose for bar and fastener stock needing better straightness, surface finish and higher yield strength. Yield strength is 305 MPa in Annealed versus 480 MPa in CD.
Sources
- ASTM B688 — Chromium-Nickel-Molybdenum-Iron (UNS N08366/N08367) Plate, Sheet, and Strip — ASTM International (2018)
- ASTM B676 / B677 — Welded and Seamless UNS N08366/N08367 Tube and Pipe — ASTM International (2019)
- ASTM B691 — UNS N08366/N08367 Rod, Bar, and Wire — ASTM International (2016)
- AL-6X / AL-6XN Alloy Technical Data — Allegheny Ludlum / ATI (2010)
- ASM Handbook Vol. 1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
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.