Stainless Steel S33550-HF (Hot Finished)
Grade
UNS S33550
Heavy plate, forged bar and rings where dimensional tolerance is coarse but section is thick.
Values for the HF condition
Other S33550 tempers and conditions
S33550 is listed in 5 conditions; see the grade overview at S33550.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
HFThis page Hot Finished | Heavy plate, forged bar and rings where dimensional tolerance is coarse but section is thick. | 300 | 670 | 42 | 175 HB | 1.5 % IACS |
ANNDefault Annealed | Standard supply condition for sheet, plate, bar and tube; best ductility, weldability and high-temperature stability. | 310 | 690 | 45 | 170 HB | 1.5 % IACS |
Cold Rolled + Annealed | Thin gauge sheet and strip for muffles, radiant tube liners and formed furnace hardware needing a clean surface. | 320 | 700 | 45 | 175 HB | 1.5 % IACS |
As-welded deposit | Property set for fabricated furnace assemblies joined with matching or Ni-base filler and used directly in service. | 340 | 650 | 32 | 185 HB | 1.5 % IACS |
Cold drawn | Choose for close-tolerance bar and fastener stock; higher strength but lower ductility and reduced hot-forming reserve. | 550 | 830 | 25 | 22 HRC | 1.5 % IACS |
What is S33550-HF?
S33550-HF is S33550 in the HF grade — heavy plate, forged bar and rings where dimensional tolerance is coarse but section is thick. S33550-HF has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 670 MPa (97.2 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 42% and the elastic modulus is 200 GPa (29 Msi). S33550-HF has a density of 8.14 g/cm³ (0.294 lb/in³), heavier than 99% of stainless steel grades. It melts at 1,330°C (2,426 °F). ANN is the default condition FabDigit quotes; HF is available on request or by drawing note.
Advantages
- High service temperature — 1,150°C (2,102 °F), better than 99% of stainless steel grades
- Tough — resists crack growth — 190 MPa·√m (172.9 ksi·√in), better than 77% of stainless steel grades
Limitations
- Low electrical conductivity — 1.5 % IACS, worse than 100% of stainless steel grades
- High embodied carbon — 8.5 kg CO₂/kg, worse than 99% 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
- Difficult to machine — 24/100, worse than 93% of stainless steel grades
S33550-HF properties
Typical room-temperature values for S33550-HF; 22 are specific to this condition. Other listed values are S33550 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S33550-HF has a density of 8.14 g/cm³ (0.294 lb/in³), heavier than 99% of stainless steel grades. It melts at 1,330°C (2,426 °F).
Mechanical16
S33550-HF has a yield strength of 300 MPa (43.5 ksi) and a tensile strength of 670 MPa (97.2 ksi) — weaker than 68% of stainless steel grades. Elongation at break is 42% and the elastic modulus is 200 GPa (29 Msi).
Thermal5
S33550-HF is rated for continuous service to 1,150°C (2,102 °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 14.4 µm/m·K (8 µin/in·°F).
Electrical3
S33550-HF conducts electricity at 1.5 % IACS, worse than 100% of stainless steel grades.
Chemical & Environmental2
Corrosion resistance is very good (70/100), better than 68% of stainless steel grades.
Sustainability4
Producing a kilogram of S33550-HF takes about 115 MJ of energy and emits 8.5 kg of CO₂ — more than 100% of stainless steel grades. Typical recycled content is 40%.
Manufacturability6
S33550-HF's machinability is poor (24/100, worse than 93% of stainless steel grades); weldability very good (75/100); formability good (62/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S33550-HF
Is S33550 easy to machine?
Machine like a nickel alloy: rigid setup, positive-rake sharp carbide, slow speed (~15–25 m/min) with heavy positive feed and flood coolant to cut under the work-hardened layer.
Can S33550 be welded?
Readily GTAW/GMAW/SMAW welded with matching or Ni-Cr-Mo filler; no preheat, low interpass temperature, no PWHT normally required, avoid heavy restraint and high heat input.
Can S33550 be formed, bent or molded?
Very ductile but strongly work hardening — allow extra press tonnage, generous bend radii and interstage solution anneals; hot work 1150–900 °C followed by rapid cooling.
What surface finishes work on S33550?
Pickle or grit blast plus passivation to remove heat-treat scale; takes a good mechanical polish, plating is rarely used and no anodizing response.
S33550 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 |
|---|---|---|
| Nifamily nominal (alloy 333 type); confirm against purchase specification | 42 – 47 | 45 |
| Croxidation/carburization resistance | 24 – 27 | 25 |
| Mo | 2.5 – 4 | 3 |
| W | 2.5 – 4 | 3 |
| Co | 2.5 – 4 | 3 |
| Sikey for carburization resistance | 0.75 – 1.5 | 1.2 |
| Mn | ≤ 2 | 1 |
| C | ≤ 0.08 | 0.05 |
| P | ≤ 0.03 | — |
| S | ≤ 0.02 | — |
| Febalance, nominally 16–20 % | balance | — |
S33550-HF — frequently asked
What is S33550-HF used for?
S33550-HF is typically used for furnace hardware, thermal-processing fixtures, carburizing and nitriding furnace retorts, radiant tube components, heat-treatment baskets and trays and muffle and retort liners. In short: carburizing-atmosphere furnace alloy; 1150 °C service austenitic; machines like nickel alloy.
What is the yield strength of S33550-HF?
S33550-HF has a typical yield strength of 300 MPa (43.5 ksi) and a tensile strength of 670 MPa (97.2 ksi) — weaker than 68% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is S33550-HF easy to machine?
Not especially — machinability is rated poor (24/100, worse than 93% of stainless steel grades). Machine like a nickel alloy: rigid setup, positive-rake sharp carbide, slow speed (~15–25 m/min) with heavy positive feed and flood coolant to cut under the work-hardened layer.
Can S33550-HF be welded?
Yes — weldability is rated very good (75/100). Readily GTAW/GMAW/SMAW welded with matching or Ni-Cr-Mo filler; no preheat, low interpass temperature, no PWHT normally required, avoid heavy restraint and high heat input.
What surface finishes work on S33550-HF?
Pickle or grit blast plus passivation to remove heat-treat scale; takes a good mechanical polish, plating is rarely used and no anodizing response.
Can S33550-HF be formed, bent or molded?
Very ductile but strongly work hardening — allow extra press tonnage, generous bend radii and interstage solution anneals; hot work 1150–900 °C followed by rapid cooling.
What is the maximum service temperature of S33550-HF?
S33550-HF is rated for continuous use to about 1,150°C (2,102 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S33550-ANN and S33550-CD?
ANN is the default condition — standard supply condition for sheet, plate, bar and tube; best ductility, weldability and high-temperature stability. CD: choose for close-tolerance bar and fastener stock; higher strength but lower ductility and reduced hot-forming reserve. Yield strength is 310 MPa in ANN versus 550 MPa in CD.
Sources
- ASM Handbook Vol.1 — Heat-Resistant Austenitic Steels and Iron-Nickel-Chromium Alloys — ASM International (1990)
- ASM Handbook Vol.13B — Corrosion in High-Temperature Environments — ASM International (2005)
- Ni-Cr-Fe furnace alloy (alloy 333 type) technical data — Rolled Alloys (2022)
- Metals & Alloys in the Unified Numbering System (UNS) — SAE/ASTM (2017)
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.