Stainless Steel S45503-H900
Precip hard
UNS S45503
H900 = 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.
Values for the H900 condition
Other S45503 tempers and conditions
S45503 is listed in 5 conditions; see the grade overview at S45503.
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 | — |
H900This page 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-H900?
S45503-H900 is S45503 in the H900 condition — maximum-strength condition (~250 ksi) for highly loaded fittings and fasteners where toughness and SCC margin are secondary. S45503-H900 has a yield strength of 1,620 MPa (235 ksi) and a tensile strength of 1,720 MPa (249 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 10% and the elastic modulus is 200 GPa (29 Msi). S45503-H900 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). H1000 is the default condition FabDigit quotes; H900 is available on request or by drawing note.
Advantages
- High strength — 1,620 MPa (235 ksi), better than 100% of stainless steel grades
- Polishes to a fine finish — 80/100, better than 89% of stainless steel grades
Limitations
- Limited ductility — 10%, worse than 98% of stainless steel grades
- Limited formability — 10/100, worse than 95% of stainless steel grades
- Low fracture toughness — 48 MPa·√m (43.7 ksi·√in), worse than 93% of stainless steel grades
- Difficult to machine — 25/100, worse than 88% of stainless steel grades
- Limited service temperature — 350°C (662 °F), worse than 84% of stainless steel grades
S45503-H900 properties
Typical room-temperature values for S45503-H900; 19 are specific to this condition. Other listed values are S45503 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
S45503-H900 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-H900 has a yield strength of 1,620 MPa (235 ksi) and a tensile strength of 1,720 MPa (249 ksi) — stronger than 100% of stainless steel grades. Elongation at break is 10% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
S45503-H900 is rated for continuous service to 350°C (662 °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-H900 conducts electricity at 2.2 % IACS, worse than 61% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 78% of stainless steel grades.
Sustainability4
Producing a kilogram of S45503-H900 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-H900's machinability is poor (25/100, worse than 88% of stainless steel grades); weldability fair (45/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with S45503-H900
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.
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.
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 | — |
S45503-H900 — frequently asked
What is S45503-H900 used for?
S45503-H900 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-H900?
S45503-H900 has a typical yield strength of 1,620 MPa (235 ksi) and a tensile strength of 1,720 MPa (249 ksi) — stronger than 100% of stainless steel grades. Strength varies by condition: see the 5 listed tempers.
Is S45503-H900 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 88% 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-H900 be welded?
With care — weldability is rated fair (45/100). 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-H900?
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-H900 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-H900?
S45503-H900 is rated for continuous use to about 350°C (662 °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.
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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.