Stainless Steel HN AS-CAST
Heat-treated state · default condition
UNS J94213
Standard supply condition for HN furnace hardware; use for all high-temperature service where creep and carburization resistance matter.
Values for the AS-CAST condition
Other HN tempers and conditions
HN is listed in 3 conditions; see the grade overview at HN.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AS-CASTDefaultThis page no heat treatment, ASTM A297/A743 HN | Standard supply condition for HN furnace hardware; use for all high-temperature service where creep and carburization resistance matter. | 255 | 470 | 11 | 175 HB | — |
HN40 centrifugally cast tube | Choose for radiant tubes, reformer/carburizing furnace tubes: centrifugal casting gives a denser, finer columnar structure and slightly higher strength than static castings. | 275 | 500 | 10 | 185 HB | 1.7 % IACS |
Aged / service-exposed | Reference condition for assessing repair or re-use of furnace parts after prolonged high-temperature service: strength rises slightly, room-temperature ductility and impact energy collapse. | 310 | 490 | 4 | 200 HB | 1.8 % IACS |
What is HN AS-CAST?
HN AS-CAST is HN heat treated to AS-CAST — standard supply condition for HN furnace hardware; use for all high-temperature service where creep and carburization resistance matter. HN AS-CAST has a yield strength of 255 MPa (37 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of stainless steel grades. Elongation at break is 11% and the elastic modulus is 180 GPa (26.1 Msi). HN AS-CAST has a density of 7.83 g/cm³ (0.283 lb/in³), heavier than 58% of stainless steel grades. It melts at 1,315°C (2,399 °F).
Advantages
- High service temperature — 1,090°C (1,994 °F), better than 93% of stainless steel grades
Limitations
- Limited formability — 5/100, worse than 99% of stainless steel grades
- Limited ductility — 11%, worse than 96% of stainless steel grades
- Hard to polish — 45/100, worse than 96% of stainless steel grades
- Low electrical conductivity — 1.7 % IACS, worse than 93% of stainless steel grades
- Poor heat conductor — 12.5 W/m·K (7.22 BTU/hr·ft·°F), worse than 90% of stainless steel grades
HN AS-CAST properties
Typical room-temperature values for HN AS-CAST; 11 are specific to this condition. Other listed values are HN reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
HN AS-CAST has a density of 7.83 g/cm³ (0.283 lb/in³), heavier than 58% of stainless steel grades. It melts at 1,315°C (2,399 °F).
Mechanical14
HN AS-CAST has a yield strength of 255 MPa (37 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of stainless steel grades. Elongation at break is 11% and the elastic modulus is 180 GPa (26.1 Msi).
Thermal6
HN AS-CAST is rated for continuous service to 1,090°C (1,994 °F). It conducts heat at 12.5 W/m·K (7.22 BTU/hr·ft·°F), worse than 90% of stainless steel grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
HN AS-CAST conducts electricity at 1.7 % IACS, worse than 93% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), worse than 58% of stainless steel grades.
Sustainability4
Producing a kilogram of HN AS-CAST takes about 60 MJ of energy and emits 5 kg of CO₂ — more than 70% of stainless steel grades. Typical recycled content is 65%.
Manufacturability7
HN AS-CAST's machinability is poor (28/100, worse than 79% of stainless steel grades); weldability fair (40/100); formability not recommended (5/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with HN AS-CAST
Is HN easy to machine?
Machine with rigid setups, sharp carbide inserts, low speed / heavy positive feed and flood coolant; the massive carbide network and rapid work hardening make interrupted cuts and small drills the main failure modes — grind rather than turn hardened service-aged parts.
Can HN be welded?
Weldable by SMAW/GTAW/FCAW with matching HN or 25Cr-35Ni filler; preheat 150–250 °C, low heat input and slow cool to limit hot cracking, and expect drastically reduced ductility when welding parts already thermally aged (solution treat at ~1100 °C first if possible).
Can HN be formed, bent or molded?
Casting-only grade — sand, investment and centrifugal casting all practical; feed heavy sections generously, avoid abrupt section changes to control hot tearing, and design generous fillets since no cold forming or straightening is possible.
What surface finishes work on HN?
Normally supplied shot-blasted or pickled; a self-healing Cr₂O₃/spinel scale forms in service and needs no coating, but aluminizing or diffusion coatings can be applied for severe carburizing/sulphidizing duty.
HN 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 |
|---|---|---|
| CHN40 subgrade (A608) narrows to 0.35–0.45 | 0.2 – 0.5 | 0.35 |
| Cr | 19 – 23 | 21 |
| Ni | 23 – 27 | 25 |
| Mn | ≤ 2 | 1.2 |
| Simax; higher Si aids oxidation resistance | ≤ 2 | 1.4 |
| Moresidual, max | ≤ 0.5 | 0.1 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Fe | balance | — |
HN AS-CAST — frequently asked
What is HN AS-CAST used for?
HN AS-CAST is typically used for carburizing furnace fixtures, radiant tubes and heat-treatment baskets. In short: best carburization resistance vs HK; good thermal-fatigue life; lower strength, higher nickel.
What is the yield strength of HN AS-CAST?
HN AS-CAST has a typical yield strength of 255 MPa (37 ksi) and a tensile strength of 470 MPa (68.2 ksi) — weaker than 87% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is HN AS-CAST easy to machine?
Not especially — machinability is rated poor (28/100, worse than 79% of stainless steel grades). Machine with rigid setups, sharp carbide inserts, low speed / heavy positive feed and flood coolant; the massive carbide network and rapid work hardening make interrupted cuts and small drills the main failure modes — grind rather than turn hardened service-aged parts.
Can HN AS-CAST be welded?
With care — weldability is rated fair (40/100). Weldable by SMAW/GTAW/FCAW with matching HN or 25Cr-35Ni filler; preheat 150–250 °C, low heat input and slow cool to limit hot cracking, and expect drastically reduced ductility when welding parts already thermally aged (solution treat at ~1100 °C first if possible).
What surface finishes work on HN AS-CAST?
Normally supplied shot-blasted or pickled; a self-healing Cr₂O₃/spinel scale forms in service and needs no coating, but aluminizing or diffusion coatings can be applied for severe carburizing/sulphidizing duty.
Can HN AS-CAST be formed, bent or molded?
Casting-only grade — sand, investment and centrifugal casting all practical; feed heavy sections generously, avoid abrupt section changes to control hot tearing, and design generous fillets since no cold forming or straightening is possible.
What is the maximum service temperature of HN AS-CAST?
HN AS-CAST is rated for continuous use to about 1,090°C (1,994 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between HN AS-CAST and HN Aged?
AS-CAST is the default condition — standard supply condition for HN furnace hardware; use for all high-temperature service where creep and carburization resistance matter. Aged: reference condition for assessing repair or re-use of furnace parts after prolonged high-temperature service: strength rises slightly, room-temperature ductility and impact energy collapse. Yield strength is 255 MPa in AS-CAST versus 310 MPa in Aged.
Sources
- ASTM A297/A297M — Steel Castings, Iron-Chromium and Iron-Chromium-Nickel, Heat Resistant, for General Application — ASTM International (2019)
- ASTM A743/A743M — Castings, Iron-Chromium, Iron-Chromium-Nickel, Corrosion Resistant, for General Application — ASTM International (2019)
- ASTM A608/A608M — Centrifugally Cast Iron-Chromium-Nickel High-Alloy Tubing for Pressure Application at High Temperatures (grade HN40) — ASTM International (2018)
- Steel Castings Handbook, Supplement 9 — High Alloy Data Sheets, Heat Series — Steel Founders' Society of America (2004)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (heat-resistant castings) — ASM International (1990)
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.