Stainless Steel 310Cb Annealed
Temper · default condition
UNS S31040
Standard stocked condition for plate, sheet, bar and pipe; maximum ductility and corrosion/oxidation resistance.
Values for the Annealed condition
Other 310Cb tempers and conditions
310Cb is listed in 4 conditions; see the grade overview at 310Cb.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Stabilize annealed | Use when maximum immunity to intergranular attack/polythionic-acid cracking after service or welding is required, by tying carbon up as NbC. | 305 | 610 | 42 | 165 HB | 2.2 % IACS |
AnnealedDefaultThis page Annealed (solution annealed, 1050–1120 °C, rapid cool) | Standard stocked condition for plate, sheet, bar and pipe; maximum ductility and corrosion/oxidation resistance. | 310 | 620 | 45 | 160 HB | — |
As-welded deposit | Reference condition for welded pipe and fabrications used without post-weld solution anneal — the reason 310Cb exists. | 330 | 600 | 35 | 180 HB | 2.2 % IACS |
Cold drawn | Pick for machined fasteners, pins and shafts needing higher yield and better surface/tolerance than hot-finished bar. | 550 | 760 | 25 | 21 HRC | — |
What is 310Cb Annealed?
310Cb Annealed is 310Cb in the Annealed temper — standard stocked condition for plate, sheet, bar and pipe; maximum ductility and corrosion/oxidation resistance. 310Cb Annealed has a yield strength of 310 MPa (45 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi). 310Cb Annealed has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% of stainless steel grades
- Tough — resists crack growth — 200 MPa·√m (182 ksi·√in), better than 86% of stainless steel grades
- Forms and bends easily — 70/100, better than 79% of stainless steel grades
- Ductile — tolerates forming and impact — 45%, better than 76% of stainless steel grades
Limitations
- High embodied carbon — 6 kg CO₂/kg, worse than 88% of stainless steel grades
310Cb Annealed properties
Typical room-temperature values for 310Cb Annealed; 11 are specific to this condition. Other listed values are 310Cb reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
310Cb Annealed has a density of 7.98 g/cm³ (0.288 lb/in³), heavier than 85% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical15
310Cb Annealed has a yield strength of 310 MPa (45 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 63% of stainless steel grades. Elongation at break is 45% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
310Cb Annealed is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 14.2 W/m·K (8.2 BTU/hr·ft·°F), worse than 76% of stainless steel grades. Thermal expansion is 15.9 µm/m·K (8.83 µin/in·°F).
Electrical3
310Cb Annealed conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 63% of stainless steel grades.
Sustainability4
Producing a kilogram of 310Cb Annealed takes about 80 MJ of energy and emits 6 kg of CO₂ — more than 89% of stainless steel grades. Typical recycled content is 70%.
Manufacturability7
310Cb Annealed's machinability is poor (30/100, worse than 70% of stainless steel grades); weldability very good (75/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 310Cb Annealed
Is 310Cb easy to machine?
Gummy and strongly work-hardening: use rigid setups, positive-rake carbide, 25–60 m/min, heavy constant feed, no dwell, flood coolant; Nb carbides accelerate edge wear.
Can 310Cb be welded?
Weld with GTAW/GMAW/SMAW using matching 310Cb/ER310 or Nb-stabilized filler, low heat input, no preheat, interpass below ~150 °C; stabilization means no post-weld solution anneal is normally needed, but watch hot cracking from fully austenitic structure.
Can 310Cb be formed, bent or molded?
Cold forms well but needs ~50 % more press force than 304 and generous bend radii due to high work-hardening and springback; hot work 1150–1200 °C, finish above 950 °C, then solution anneal.
What surface finishes work on 310Cb?
Pickle and passivate or electropolish after fabrication to restore the chromium oxide film; no anodizing — descale heat tint with acid paste or abrasive blast plus passivation.
310Cb 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 |
|---|---|---|
| CNb stabilization ties up carbon as NbC | ≤ 0.08 | 0.05 |
| Mn | ≤ 2 | 1.5 |
| Sisome specs limit to 0.75 max | ≤ 1.5 | 0.8 |
| P | ≤ 0.05 | — |
| S | ≤ 0.03 | — |
| Cr | 24 – 26 | 25 |
| Ni | 19 – 22 | 20.5 |
| NbNb (+Ta) stabilizer; historically written as Cb | 0.75 – 1.5 | 1 |
| Fe | balance | — |
310Cb Annealed — frequently asked
What is 310Cb Annealed used for?
310Cb Annealed is typically used for furnace components and hangers, welded high-temperature ducting, radiant tubes, heat-treating fixtures, recuperator sections and flue and stack liners. In short: stabilized 310 for welding; resists post-service sensitization; 1100 °C furnace grade.
What is the yield strength of 310Cb Annealed?
310Cb Annealed has a typical yield strength of 310 MPa (45 ksi) and a tensile strength of 620 MPa (89.9 ksi) — weaker than 63% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is 310Cb Annealed easy to machine?
Not especially — machinability is rated poor (30/100, worse than 70% of stainless steel grades). Gummy and strongly work-hardening: use rigid setups, positive-rake carbide, 25–60 m/min, heavy constant feed, no dwell, flood coolant; Nb carbides accelerate edge wear.
Can 310Cb Annealed be welded?
Yes — weldability is rated very good (75/100). Weld with GTAW/GMAW/SMAW using matching 310Cb/ER310 or Nb-stabilized filler, low heat input, no preheat, interpass below ~150 °C; stabilization means no post-weld solution anneal is normally needed, but watch hot cracking from fully austenitic structure.
What surface finishes work on 310Cb Annealed?
Pickle and passivate or electropolish after fabrication to restore the chromium oxide film; no anodizing — descale heat tint with acid paste or abrasive blast plus passivation.
Can 310Cb Annealed be formed, bent or molded?
Cold forms well but needs ~50 % more press force than 304 and generous bend radii due to high work-hardening and springback; hot work 1150–1200 °C, finish above 950 °C, then solution anneal.
What is the maximum service temperature of 310Cb Annealed?
310Cb Annealed is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 310Cb Annealed and 310Cb-CD?
Annealed is the default condition — standard stocked condition for plate, sheet, bar and pipe; maximum ductility and corrosion/oxidation resistance. CD: pick for machined fasteners, pins and shafts needing higher yield and better surface/tolerance than hot-finished bar. Yield strength is 310 MPa in Annealed versus 550 MPa in CD.
Sources
- ASTM A240/A240M — Chromium and Chromium-Nickel Stainless Steel Plate, Sheet and Strip (UNS S31040) — ASTM International (2023)
- ASTM A479/A312 — stainless bar and welded/seamless pipe requirements — ASTM International (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Specialty Handbook — Stainless Steels — ASM International (1994)
- 310/310S/310Cb heat-resisting stainless datasheets — Outokumpu / Sandvik / NAS (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.