Stainless Steel S45503
UNS S45503
S45503 is a restricted-composition variant of Custom 455 (S45500), a Ti/Cu-strengthened martensitic precipitation-hardening stainless with tighter chemistry control for more consistent toughness in critical aerospace forgings.
Reference datasheet — S45503 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 H1000 condition
S45503 tempers and conditions
S45503 is supplied in 5 conditions, soft to hard. H1000 is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Supply/stock condition for machining, forming and welding before the customer performs the single-step age. | 795 | 1,030 | 14 | 30 HRC | — |
Aged 4 h at 566 °C (1050 °F), air cool | Overaged, toughest condition (~200 ksi) for thick sections or parts needing maximum SCC and hydrogen-embrittlement margin. | 1,310 | 1,400 | 13 | 40 HRC | — |
H1000Default Aged 4 h at 538 °C (1000 °F), air cool | Default stocked aged condition: ~220 ksi with the best strength/toughness/SCC balance for aerospace forgings and shafts. | 1,450 | 1,520 | 12 | 44 HRC | — |
Aged 4 h at 510 °C (950 °F), air cool | Common aerospace compromise: ~235 ksi with better ductility and SCC behaviour than H900. | 1,550 | 1,620 | 11 | 47 HRC | — |
Aged 482 °C (900 °F) for 1 h, peak hardness | Maximum-strength condition (~250 ksi) for highly loaded fittings and fasteners where toughness and SCC margin are secondary. | 1,620 | 1,720 | 10 | 49 HRC | — |
What is S45503?
S45503 is a restricted-composition variant of Custom 455 (S45500), a Ti/Cu-strengthened martensitic precipitation-hardening stainless with tighter chemistry control for more consistent toughness in critical aerospace forgings. Aged properties reach about 1450 MPa yield, 1520 MPa tensile, 12 % elongation and 44 HRC, with service to 425 °C and H900 through H1050 tempers on file. It machines and welds better than most stainless steels at this strength level (scores 32 and 55), but formability is minimal (15) and corrosion resistance is moderate. Choose standard S45500 when restricted-chemistry certification is not required. S45503 has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 58% of stainless steel grades. It melts at 1,400°C (2,552 °F). S45503 has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,520 MPa (220 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
What is S45503 used for?
- Aircraft landing gear components
- High-strength precision forgings
- Actuator rods and pistons
- Flap and slat track hardware
- Torque tubes and drive shafts
- Fasteners and high-load fittings
Advantages
- High strength — 1,450 MPa (210 ksi), better than 99% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
Limitations
- Limited ductility — 12%, worse than 95% of stainless steel grades
- Limited formability — 15/100, worse than 91% of stainless steel grades
- Low fracture toughness — 65 MPa·√m (59.2 ksi·√in), worse than 85% of stainless steel grades
S45503 properties
Typical room-temperature values for S45503-H1000; bars are the position among stainless steel grades.
Physical3
S45503 has a density of 7.76 g/cm³ (0.28 lb/in³), lighter than 58% of stainless steel grades. It melts at 1,400°C (2,552 °F).
Mechanical16
S45503 has a yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,520 MPa (220 ksi) — stronger than 99% of stainless steel grades. Elongation at break is 12% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S45503 is rated for continuous service to 425°C (797 °F). It conducts heat at 17.9 W/m·K (10.3 BTU/hr·ft·°F), better than 73% of stainless steel grades. Thermal expansion is 10.3 µm/m·K (5.72 µin/in·°F).
Electrical3
S45503 conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 71% of stainless steel grades.
Sustainability4
Producing a kilogram of S45503 takes about 58 MJ of energy and emits 4.6 kg of CO₂ — more than 66% of stainless steel grades. Typical recycled content is 35%.
Manufacturability8
S45503's machinability is poor (32/100, worse than 62% of stainless steel grades); weldability good (55/100); formability poor (15/100).
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. S45503 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with S45503
Is S45503 easy to machine?
Rough machine in Condition A (~30 HRC) then age; in H900–H1000 use rigid setups, positive-rake carbide or ceramic inserts, slow speeds and heavy flood coolant — work hardens readily.
Can S45503 be welded?
GTAW/EBW with matching or 455 filler is feasible; avoid excessive heat input, then re-solution-treat plus age (or at minimum re-age) to restore joint strength.
Can S45503 be formed, bent or molded?
Form, bend and thread only in the solution-annealed condition; aging causes minimal (<0.1 %) dimensional change so final geometry can be cut before heat treatment.
S45503 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 |
|---|---|---|
| Crestricted vs 0.05 max of S45500 | ≤ 0.03 | 0.02 |
| Mn | ≤ 0.5 | 0.25 |
| Si | ≤ 0.5 | 0.2 |
| Prestricted-composition limit | ≤ 0.02 | 0.01 |
| Srestricted-composition limit for transverse toughness | ≤ 0.01 | 0 |
| Cr | 11 – 12.5 | 11.75 |
| Ni | 7.5 – 9.5 | 8.5 |
| Cuco-precipitation strengthener | 1.5 – 2.5 | 2.25 |
| Tiprimary η-Ni3Ti strengthener | 0.8 – 1.4 | 1.2 |
| NbNb+Ta | 0.1 – 0.5 | 0.3 |
| Mo | ≤ 0.5 | 0.2 |
| Fe | balance |
What surface finishes work on S45503?
Passivate per AMS 2700 after machining; takes a high polish, and for aged parts above ~1300 MPa avoid electroplating or bake immediately to prevent hydrogen embrittlement.
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 S45503 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Custom 455
- Similar grades
- S45500
How much does S45503 cost?
S45503 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.
S45503 — frequently asked
What is S45503 used for?
S45503 is typically used for aircraft landing gear components, high-strength precision forgings, actuator rods and pistons, flap and slat track hardware, torque tubes and drive shafts and fasteners and high-load fittings. In short: highest-strength PH stainless here; tight-chemistry Custom 455; minimal ageing distortion.
What is the yield strength of S45503?
S45503 has a typical yield strength of 1,450 MPa (210 ksi) and a tensile strength of 1,520 MPa (220 ksi) — stronger than 99% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is S45503 easy to machine?
Not especially — machinability is rated poor (32/100, worse than 62% of stainless steel grades). Rough machine in Condition A (~30 HRC) then age; in H900–H1000 use rigid setups, positive-rake carbide or ceramic inserts, slow speeds and heavy flood coolant — work hardens readily.
Can S45503 be welded?
Yes — weldability is rated good (55/100). GTAW/EBW with matching or 455 filler is feasible; avoid excessive heat input, then re-solution-treat plus age (or at minimum re-age) to restore joint strength.
What surface finishes work on S45503?
Passivate per AMS 2700 after machining; takes a high polish, and for aged parts above ~1300 MPa avoid electroplating or bake immediately to prevent hydrogen embrittlement.
Can S45503 be formed, bent or molded?
Form, bend and thread only in the solution-annealed condition; aging causes minimal (<0.1 %) dimensional change so final geometry can be cut before heat treatment.
What is the maximum service temperature of S45503?
S45503 is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between S45503-H1000 and S45503-A?
H1000 is the default condition — default stocked aged condition: ~220 ksi with the best strength/toughness/SCC balance for aerospace forgings and shafts. A: supply/stock condition for machining, forming and welding before the customer performs the single-step age. Yield strength is 1,450 MPa in H1000 versus 795 MPa in A.
How much does S45503 cost?
S45503 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
- AMS 5617 — Steel, Corrosion-Resistant, Bars and Forgings 11.75Cr-8.5Ni-2.25Cu-1.2Ti (Custom 455) — SAE International (2018)
- ASTM A564/A564M — Hot-Rolled and Cold-Finished Age-Hardening Stainless Steel Bars and Shapes — ASTM International (2019)
- Custom 455 Stainless alloy technical datasheet — Carpenter Technology (2021)
- ASM Handbook Vol.1: Properties and Selection — Irons, Steels and High-Performance Alloys — ASM International (1990)
- MMPDS-17 — Metallic Materials Properties Development and Standardization — Battelle/FAA (2022)
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.