Stainless Steel HL Aged
Heat-treated state
UNS N08604
Aged = service-exposed / thermally aged
Reference condition for repair and life assessment: carbide coarsening and σ-phase drop room-temperature ductility and impact energy sharply.
Values for the Aged condition
Other HL tempers and conditions
HL is listed in 3 conditions; see the grade overview at HL.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
FDefault As fabricated | Standard supply condition for HL furnace hardware — used as cast, no post-cast heat treatment. | 340 | 565 | 15 | 192 HB | 1.8 % IACS |
Centrifugally cast tube/ring | Pick for radiant tubes, rolls and sleeves where the denser, directionally solidified centrifugal structure gives higher soundness and creep life. | 360 | 600 | 17 | 200 HB | 1.8 % IACS |
AgedThis page Service-exposed / thermally aged | Reference condition for repair and life assessment: carbide coarsening and σ-phase drop room-temperature ductility and impact energy sharply. | 380 | 540 | 4 | 220 HB | 1.9 % IACS |
What is HL Aged?
HL Aged is HL heat treated to Aged — reference condition for repair and life assessment: carbide coarsening and σ-phase drop room-temperature ductility and impact energy sharply. HL Aged has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 4% and the elastic modulus is 175 GPa (25.4 Msi). HL Aged has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,340°C (2,444 °F). F is the default condition FabDigit quotes; Aged is available on request or by drawing note.
Advantages
- High service temperature — 1,100°C (2,012 °F), better than 96% of stainless steel grades
Limitations
- Limited ductility — 4%, worse than 100% of stainless steel grades
- Limited formability — 3/100, worse than 100% of stainless steel grades
- Low stiffness — 175 GPa (25.4 Msi), worse than 99% of stainless steel grades
- Hard to polish — 45/100, worse than 96% of stainless steel grades
- Difficult to machine — 22/100, worse than 95% of stainless steel grades
HL Aged properties
Typical room-temperature values for HL Aged; 23 are specific to this condition. Other listed values are HL reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
HL Aged has a density of 7.7 g/cm³ (0.278 lb/in³), lighter than 83% of stainless steel grades. It melts at 1,340°C (2,444 °F).
Mechanical15
HL Aged has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — stronger than 52% of stainless steel grades. Elongation at break is 4% and the elastic modulus is 175 GPa (25.4 Msi).
Thermal6
HL Aged is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 14.5 W/m·K (8.38 BTU/hr·ft·°F), worse than 72% of stainless steel grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
HL Aged conducts electricity at 1.9 % IACS, worse than 84% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (54/100), worse than 75% of stainless steel grades.
Sustainability4
Producing a kilogram of HL Aged takes about 62 MJ of energy and emits 4.6 kg of CO₂ — more than 75% of stainless steel grades. Typical recycled content is 70%.
Manufacturability8
HL Aged's machinability is poor (22/100, worse than 95% of stainless steel grades); weldability poor (20/100); formability not recommended (3/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with HL Aged
Is HL easy to machine?
Machine with rigid setups, sharp carbide or ceramic tooling, low speed/heavy positive feed to cut under the work-hardened skin; grind rather than turn heavily aged material.
Can HL be welded?
Weld with matching HL/high-Cr-Ni or 25-20 (ER310) filler, preheat 150–250 °C, low heat input and slow cooling; service-aged castings should be solution-annealed or buttered before repair welding to avoid hot cracking.
Can HL be formed, bent or molded?
Casting alloy only — sand, investment or centrifugal cast with generous risering and controlled section transitions; no cold forming, hot straightening above 1000 °C only.
What surface finishes work on HL?
Shot blast and pickle/passivate after casting; aluminizing or ceramic coating can extend life in high-sulfur ash, but painting and anodizing are not applicable.
HL 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 |
|---|---|---|
| Chigh C for creep strength | 0.2 – 0.6 | 0.4 |
| Mn | ≤ 2 | 1.2 |
| Siaids scaling resistance | ≤ 2 | 1.5 |
| P | ≤ 0.04 | — |
| S | ≤ 0.04 | — |
| Crhigher than HK for sulfidation/scaling resistance | 28 – 32 | 30 |
| Ni | 18 – 22 | 20 |
| Moresidual only | ≤ 0.5 | — |
| Fe | balance | — |
HL Aged — frequently asked
What is HL Aged used for?
HL Aged is typically used for furnace muffles, heat-treatment fixtures and combustion chamber parts. In short: better scaling than HK; sulfidizing-atmosphere furnace castings; cast-only, no cold forming.
What is the yield strength of HL Aged?
HL Aged has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 540 MPa (78.3 ksi) — stronger than 52% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is HL Aged easy to machine?
Not especially — machinability is rated poor (22/100, worse than 95% of stainless steel grades). Machine with rigid setups, sharp carbide or ceramic tooling, low speed/heavy positive feed to cut under the work-hardened skin; grind rather than turn heavily aged material.
Can HL Aged be welded?
Not readily — weldability is rated poor (20/100). Weld with matching HL/high-Cr-Ni or 25-20 (ER310) filler, preheat 150–250 °C, low heat input and slow cooling; service-aged castings should be solution-annealed or buttered before repair welding to avoid hot cracking.
What surface finishes work on HL Aged?
Shot blast and pickle/passivate after casting; aluminizing or ceramic coating can extend life in high-sulfur ash, but painting and anodizing are not applicable.
Can HL Aged be formed, bent or molded?
Casting alloy only — sand, investment or centrifugal cast with generous risering and controlled section transitions; no cold forming, hot straightening above 1000 °C only.
What is the maximum service temperature of HL Aged?
HL Aged 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 HL-F and HL Aged?
F is the default condition — standard supply condition for HL furnace hardware — used as cast, no post-cast heat treatment. Aged: reference condition for repair and life assessment: carbide coarsening and σ-phase drop room-temperature ductility and impact energy sharply. Yield strength is 340 MPa in F versus 380 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)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys (Heat-Resistant Castings) — ASM International (1990)
- Steel Castings Handbook, 6th ed. — High Alloy Data Sheets, Heat Series — Steel Founders' Society of America (1995)
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.