Stainless Steel N08320 1/4H
Supply condition
UNS N08320
1/4H = quarter hard
Choose for springs, diaphragms and formed strip parts where extra strength is needed and full annealed ductility is not; sensitive to stress corrosion in hot chloride service.
Values for the 1/4H condition
Other N08320 tempers and conditions
N08320 is listed in 4 conditions; see the grade overview at N08320.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Hot Finished + Annealed | Choose for heavy sections, forgings and thick plate where hot working precedes the anneal; properties essentially the same as annealed with slightly lower strength in very heavy sections. | 255 | 565 | 45 | 150 HB | 1.7 % IACS |
AnnealedDefault solution annealed ~1010–1120 °C, rapid quench | Standard supply condition for plate, sheet, bar and tube in corrosive chemical process service; maximum corrosion resistance and ductility. | 265 | 585 | 45 | 160 HB | — |
Cold drawn | Choose for fasteners, shafts and pump/valve parts needing higher strength and better dimensional tolerance than annealed bar; slightly reduced ductility and corrosion margin. | 550 | 760 | 25 | 220 HB | — |
1/4HThis page Quarter hard | Choose for springs, diaphragms and formed strip parts where extra strength is needed and full annealed ductility is not; sensitive to stress corrosion in hot chloride service. | 620 | 860 | 18 | 25 HRC | 1.7 % IACS |
What is N08320 1/4H?
N08320 1/4H is N08320 supplied in the 1/4H condition — choose for springs, diaphragms and formed strip parts where extra strength is needed and full annealed ductility is not; sensitive to stress corrosion in hot chloride service. N08320 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 18% and the elastic modulus is 198 GPa (28.7 Msi). N08320 1/4H has a density of 8.08 g/cm³ (0.292 lb/in³), heavier than 99% of stainless steel grades. It melts at 1,370°C (2,498 °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 — 73/100, better than 77% of stainless steel grades
Limitations
- Poor heat conductor — 11.5 W/m·K (6.64 BTU/hr·ft·°F), worse than 97% of stainless steel grades
- Difficult to machine — 22/100, worse than 95% of stainless steel grades
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- Limited service temperature — 300°C (572 °F), worse than 90% of stainless steel grades
- High embodied carbon — 6.2 kg CO₂/kg, worse than 90% of stainless steel grades
N08320 1/4H properties
Typical room-temperature values for N08320 1/4H; 24 are specific to this condition. Other listed values are N08320 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
N08320 1/4H has a density of 8.08 g/cm³ (0.292 lb/in³), heavier than 99% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical13
N08320 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 18% and the elastic modulus is 198 GPa (28.7 Msi).
Thermal6
N08320 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 14.6 µm/m·K (8.11 µin/in·°F).
Electrical3
N08320 1/4H conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is very good (73/100), better than 77% of stainless steel grades.
Sustainability4
Producing a kilogram of N08320 1/4H takes about 85 MJ of energy and emits 6.2 kg of CO₂ — more than 92% of stainless steel grades. Typical recycled content is 40%.
Manufacturability7
N08320 1/4H's machinability is poor (22/100, worse than 95% of stainless steel grades); weldability very good (72/100); formability fair (35/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with N08320 1/4H
Is N08320 easy to machine?
Gummy and work-hardening like other high-Ni austenitics: use rigid setups, positive-rake sharp carbide, heavy positive feeds, low-to-moderate speeds (~20–35 m/min turning) and copious sulfochlorinated or emulsion coolant; never dwell or rub.
Can N08320 be welded?
Readily welded by GTAW/GMAW/SMAW with matching N08320 filler or over-alloyed Ni-base filler (ERNiCrMo-3); keep interpass below ~150 °C, low heat input, no preheat, and avoid post-weld sensitizing exposures — Ti stabilization protects HAZ.
Can N08320 be formed, bent or molded?
Cold forms well in the annealed condition but work-hardens rapidly, so allow 40–60% more press force than 304 and plan interstage anneals at 1010–1120 °C with rapid quench; hot work 1150–1230 °C, do not finish below ~950 °C.
What surface finishes work on N08320?
Pickle (HNO₃-HF) or grit-blast plus passivation after hot work/welding to restore the passive film; electropolishing gives the best surface for acid-service vessels — anodizing is not applicable.
N08320 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 |
|---|---|---|
| C | ≤ 0.05 | 0.03 |
| Mn | ≤ 2.5 | 1 |
| Si | ≤ 1 | 0.5 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cr | 21 – 23 | 22 |
| Ni | 25 – 27 | 26 |
| Mo | 4 – 6 | 5 |
| Cu | ≤ 0.4 | 0.2 |
| Ti4×C minimum (stabilization against sensitization) | ≤ 0.6 | 0.3 |
| Febalance, approx. 42–46% | balance | — |
N08320 1/4H — frequently asked
What is N08320 1/4H used for?
N08320 1/4H is typically used for sulfuric and phosphoric acid handling, chemical reactor vessels, scrubber and pollution control equipment and heat exchangers in aggressive media. In short: reducing-acid superaustenitic; ti-stabilized against HAZ sensitization; weldable high-Mo austenitic.
What is the yield strength of N08320 1/4H?
N08320 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 N08320 1/4H easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% of stainless steel grades). Gummy and work-hardening like other high-Ni austenitics: use rigid setups, positive-rake sharp carbide, heavy positive feeds, low-to-moderate speeds (~20–35 m/min turning) and copious sulfochlorinated or emulsion coolant; never dwell or rub.
Can N08320 1/4H be welded?
Yes — weldability is rated very good (72/100). Readily welded by GTAW/GMAW/SMAW with matching N08320 filler or over-alloyed Ni-base filler (ERNiCrMo-3); keep interpass below ~150 °C, low heat input, no preheat, and avoid post-weld sensitizing exposures — Ti stabilization protects HAZ.
What surface finishes work on N08320 1/4H?
Pickle (HNO₃-HF) or grit-blast plus passivation after hot work/welding to restore the passive film; electropolishing gives the best surface for acid-service vessels — anodizing is not applicable.
Can N08320 1/4H be formed, bent or molded?
Cold forms well in the annealed condition but work-hardens rapidly, so allow 40–60% more press force than 304 and plan interstage anneals at 1010–1120 °C with rapid quench; hot work 1150–1230 °C, do not finish below ~950 °C.
What is the maximum service temperature of N08320 1/4H?
N08320 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 N08320 Annealed and N08320-CD?
Annealed is the default condition — standard supply condition for plate, sheet, bar and tube in corrosive chemical process service; maximum corrosion resistance and ductility. CD: choose for fasteners, shafts and pump/valve parts needing higher strength and better dimensional tolerance than annealed bar; slightly reduced ductility and corrosion margin. Yield strength is 265 MPa in Annealed versus 550 MPa in CD.
Sources
- ASTM B620 — Ni-Fe-Cr-Mo Alloy (UNS N08320) Plate, Sheet, and Strip — ASTM International (2019)
- ASTM B621 — Ni-Fe-Cr-Mo Alloy (UNS N08320) Rod and Bar — ASTM International (2019)
- ASTM B622 — Seamless Nickel and Nickel-Alloy Pipe and Tube — ASTM International (2021)
- Carpenter 20Mo-4 Alloy Technical Data — Carpenter Technology (2020)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
- ASM Specialty Handbook: Stainless Steels — ASM International (1994)
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.