Stainless Steel HD Aged
Heat-treated state
UNS J93005 · ASTM A297 Grade HD
Aged = aged / service-exposed
Represents the embrittled condition after prolonged exposure in the 600–900 °C range; use these values for design checks on repair, handling and thermal-cycling loads.
Values for the Aged condition
Other HD tempers and conditions
HD is listed in 3 conditions; see the grade overview at HD.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed ~1040–1065 °C, rapid cool | Optional treatment used to dissolve grain-boundary carbides and re-solution sigma phase, giving the best available room-temperature ductility before machining or welding. | 320 | 560 | 18 | 180 HB | 2.1 % IACS |
FDefault As fabricated | Standard supply condition for all A297 HD castings; no heat treatment is required or normally applied. | 345 | 585 | 16 | 12 HRC | 2 % IACS |
AgedThis page Aged / service-exposed | Represents the embrittled condition after prolonged exposure in the 600–900 °C range; use these values for design checks on repair, handling and thermal-cycling loads. | 415 | 655 | 4 | 20 HRC | 2 % IACS |
What is HD Aged?
HD Aged is HD heat treated to Aged — represents the embrittled condition after prolonged exposure in the 600–900 °C range; use these values for design checks on repair, handling and thermal-cycling loads. HD Aged has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Elongation at break is 4% and the elastic modulus is 200 GPa (29 Msi). HD Aged has a density of 7.6 g/cm³ (0.275 lb/in³), lighter than 98% of stainless steel grades. It melts at 1,370°C (2,498 °F). F is the default condition FabDigit quotes; Aged is available on request or by drawing note.
Advantages
- High service temperature — 1,090°C (1,994 °F), better than 93% of stainless steel grades
- Low embodied carbon — 3.6 kg CO₂/kg, better than 83% of stainless steel grades
Limitations
- Limited ductility — 4%, worse than 100% of stainless steel grades
- Limited formability — 2/100, worse than 100% of stainless steel grades
- Difficult to machine — 18/100, worse than 99% of stainless steel grades
- Difficult to weld — 15/100, worse than 98% of stainless steel grades
- Hard to polish — 45/100, worse than 96% of stainless steel grades
HD Aged properties
Typical room-temperature values for HD Aged; 23 are specific to this condition. Other listed values are HD reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
HD Aged has a density of 7.6 g/cm³ (0.275 lb/in³), lighter than 98% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical15
HD Aged has a yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Elongation at break is 4% and the elastic modulus is 200 GPa (29 Msi).
Thermal5
HD Aged is rated for continuous service to 1,090°C (1,994 °F). It conducts heat at 20 W/m·K (11.6 BTU/hr·ft·°F), better than 74% of stainless steel grades. Thermal expansion is 11.5 µm/m·K (6.39 µin/in·°F).
Electrical3
HD Aged conducts electricity at 2 % IACS, worse than 77% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (52/100), worse than 76% of stainless steel grades.
Sustainability4
Producing a kilogram of HD Aged takes about 50 MJ of energy and emits 3.6 kg of CO₂ — less than 80% of stainless steel grades. Typical recycled content is 75%.
Manufacturability8
HD Aged's machinability is poor (18/100, worse than 99% of stainless steel grades); weldability poor (15/100); formability not recommended (2/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with HD Aged
Is HD easy to machine?
Machine with rigid setups, positive-rake carbide, low speed and heavy feed to cut below the work-hardened skin; abrasive carbides give short tool life, so grinding is often preferred for finish surfaces.
Can HD be welded?
Weldable with E/ER 312 (29-9) or matching HD filler; preheat 150–260 °C, keep interpass moderate and slow-cool, then optionally solution anneal — as-cast and aged material is crack-sensitive.
Can HD be formed, bent or molded?
Sand or investment cast only; good fluidity but design generous fillets and avoid restrained sections because of the low hot ductility and high shrinkage of high-Cr alloys.
What surface finishes work on HD?
Normally supplied shot-blasted as-cast; passivate or leave the self-forming Cr₂O₃ scale — no anodizing, and plating adheres poorly to the cast skin.
HD 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 |
|---|---|---|
| C0.50 % max per ASTM A297 | ≤ 0.5 | 0.4 |
| Mn | ≤ 1.5 | 1 |
| Sihigh Si aids scaling resistance | ≤ 2 | 1.5 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Cr | 26 – 30 | 28 |
| Ni | 4 – 7 | 5.5 |
| Moresidual, not intentionally added | ≤ 0.5 | — |
| Fe | balance | — |
HD Aged — frequently asked
What is HD Aged used for?
HD Aged is typically used for radiant tube supports, furnace fixtures, heat treatment baskets and high-temperature process equipment. In short: stronger than Grade HC; 28Cr-5Ni heat-resisting casting; 1090 °C oxidizing service.
What is the yield strength of HD Aged?
HD Aged has a typical yield strength of 415 MPa (60.2 ksi) and a tensile strength of 655 MPa (95 ksi) — stronger than 62% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is HD Aged easy to machine?
Not especially — machinability is rated poor (18/100, worse than 99% of stainless steel grades). Machine with rigid setups, positive-rake carbide, low speed and heavy feed to cut below the work-hardened skin; abrasive carbides give short tool life, so grinding is often preferred for finish surfaces.
Can HD Aged be welded?
Not readily — weldability is rated poor (15/100). Weldable with E/ER 312 (29-9) or matching HD filler; preheat 150–260 °C, keep interpass moderate and slow-cool, then optionally solution anneal — as-cast and aged material is crack-sensitive.
What surface finishes work on HD Aged?
Normally supplied shot-blasted as-cast; passivate or leave the self-forming Cr₂O₃ scale — no anodizing, and plating adheres poorly to the cast skin.
Can HD Aged be formed, bent or molded?
Sand or investment cast only; good fluidity but design generous fillets and avoid restrained sections because of the low hot ductility and high shrinkage of high-Cr alloys.
What is the maximum service temperature of HD Aged?
HD Aged 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 HD-F and HD Aged?
F is the default condition — standard supply condition for all A297 HD castings; no heat treatment is required or normally applied. Aged: represents the embrittled condition after prolonged exposure in the 600–900 °C range; use these values for design checks on repair, handling and thermal-cycling loads. Yield strength is 345 MPa in F versus 415 MPa in Aged.
Sources
- ASTM A297/A297M — Steel Castings, Iron-Chromium and Iron-Chromium-Nickel, Heat Resistant, for General Application — ASTM International (2019)
- High Alloy Data Sheets, Heat Series (Grade HD) — Steel Founders' Society of America (SFSA) (2004)
- ASM Handbook Vol. 1: Properties and Selection — Irons, Steels, and High-Performance Alloys (Heat-Resistant Castings) — 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.