Stainless Steel HL
UNS N08604
HL is a high-chromium heat-resistant cast stainless steel (UNS N08604) to ASTM A297 and A743, supplied as-cast, centrifugally cast or in the aged condition.
Reference datasheet — HL is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the F condition
HL tempers and conditions
HL is supplied in 3 conditions, soft to hard. F is the default FabDigit quotes; the values on this page are for it.
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 |
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?
HL is a high-chromium heat-resistant cast stainless steel (UNS N08604) to ASTM A297 and A743, supplied as-cast, centrifugally cast or in the aged condition. Its raised chromium content gives better scaling resistance than HK in aggressive oxidizing and sulfidizing furnace atmospheres, with 340 MPa yield, 565 MPa tensile, 15% elongation, 192 HB and service to about 1150 °C. It is a casting grade with no cold-forming route, and aged material must be solution-annealed or buttered before repair welding. HK remains the cheaper and more widely stocked choice where sulfur attack is not the limiting factor. HL 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). HL has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 565 MPa (81.9 ksi) — weaker than 55% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 180 GPa (26.1 Msi).
What is HL used for?
- furnace muffles
- heat-treatment fixtures
- combustion chamber parts
Advantages
- High service temperature — 1,150°C (2,102 °F), better than 99% of stainless steel grades
Limitations
- Hard to polish — 45/100, worse than 96% of stainless steel grades
- Limited formability — 10/100, worse than 95% of stainless steel grades
- Limited ductility — 15%, worse than 89% of stainless steel grades
- Low electrical conductivity — 1.8 % IACS, worse than 87% of stainless steel grades
- Difficult to weld — 40/100, worse than 83% of stainless steel grades
HL properties
Typical room-temperature values for HL-F; bars are the position among stainless steel grades.
Physical3
HL 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 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 565 MPa (81.9 ksi) — weaker than 55% of stainless steel grades. Elongation at break is 15% and the elastic modulus is 180 GPa (26.1 Msi).
Thermal6
HL is rated for continuous service to 1,150°C (2,102 °F). It conducts heat at 13.5 W/m·K (7.8 BTU/hr·ft·°F), worse than 83% of stainless steel grades. Thermal expansion is 15.5 µm/m·K (8.61 µin/in·°F).
Electrical3
HL conducts electricity at 1.8 % IACS, worse than 87% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of HL 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's machinability is poor (28/100, worse than 79% of stainless steel grades); weldability fair (40/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the stainless steel family
Yield strength against density for every stainless steel grade FabDigit runs. HL is highlighted; hover a dot for its name, or open the interactive family chart.
Working with HL
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.
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 |
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.
Surface treatments FabDigit runs on stainless steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Organic Coating
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Stainless Steel HL in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- N08604
How much does HL cost?
HL is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
HL — frequently asked
What is HL used for?
HL 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?
HL has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 565 MPa (81.9 ksi) — weaker than 55% of stainless steel grades. Strength varies by condition: see the 3 listed tempers.
Is HL easy to machine?
Not especially — machinability is rated poor (28/100, worse than 79% 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 be welded?
With care — weldability is rated fair (40/100). 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?
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 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?
HL 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 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.
How much does HL cost?
HL is a high-cost stainless steel ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.