Stainless Steel V-57-STA (Solution treated and aged)
Heat-treated state · default condition
UNS S51770
Standard aerospace bar/forging condition — best balance of strength, ductility and 650 °C creep performance.
Values for the STA condition
Other V-57 tempers and conditions
V-57 is listed in 4 conditions; see the grade overview at V-57.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Soft supply condition for cold forming, deep drawing, machining of complex shapes and welding before aging. | 275 | 690 | 45 | 170 HB | — |
STADefaultThis page Solution treated and aged | Standard aerospace bar/forging condition — best balance of strength, ductility and 650 °C creep performance. | 725 | 1,070 | 20 | 32 HRC | — |
Solution treated ~900 °C (1650 °F) + aged 720 °C/16 h | Fine-grain low-temperature solution route for maximum room-temperature strength and notch ductility in fasteners and shafts. | 795 | 1,140 | 18 | 34 HRC | — |
Cold drawn/cold worked then aged | Choose for high-strength bolts, studs and springs where cold work plus aging pushes strength above the standard STA level. | 1,035 | 1,240 | 12 | 38 HRC | — |
What is V-57-STA?
V-57-STA is V-57 heat treated to STA — standard aerospace bar/forging condition — best balance of strength, ductility and 650 °C creep performance. V-57-STA has a yield strength of 725 MPa (105 ksi) and a tensile strength of 1,070 MPa (155 ksi) — stronger than 93% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 201 GPa (29.2 Msi). V-57-STA has a density of 7.92 g/cm³ (0.286 lb/in³), heavier than 77% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Advantages
- High strength — 725 MPa (105 ksi), better than 93% of stainless steel grades
Limitations
- Difficult to machine — 20/100, worse than 98% of stainless steel grades
- High embodied carbon — 6.8 kg CO₂/kg, worse than 95% of stainless steel grades
- Low electrical conductivity — 1.9 % IACS, worse than 84% of stainless steel grades
- Difficult to weld — 40/100, worse than 83% of stainless steel grades
- Limited ductility — 20%, worse than 79% of stainless steel grades
V-57-STA properties
Typical room-temperature values for V-57-STA; 18 are specific to this condition. Other listed values are V-57 reference data and may not represent this condition. Bars are the position among stainless steel grades.
Physical3
V-57-STA has a density of 7.92 g/cm³ (0.286 lb/in³), heavier than 77% of stainless steel grades. It melts at 1,370°C (2,498 °F).
Mechanical16
V-57-STA has a yield strength of 725 MPa (105 ksi) and a tensile strength of 1,070 MPa (155 ksi) — stronger than 93% of stainless steel grades. Elongation at break is 20% and the elastic modulus is 201 GPa (29.2 Msi).
Thermal6
V-57-STA is rated for continuous service to 650°C (1,202 °F). It conducts heat at 14 W/m·K (8.09 BTU/hr·ft·°F), worse than 80% of stainless steel grades. Thermal expansion is 16.5 µm/m·K (9.17 µin/in·°F).
Electrical3
V-57-STA conducts electricity at 1.9 % IACS, worse than 84% of stainless steel grades.
Chemical & Environmental3
Corrosion resistance is good (62/100), worse than 52% of stainless steel grades.
Sustainability4
Producing a kilogram of V-57-STA takes about 95 MJ of energy and emits 6.8 kg of CO₂ — more than 96% of stainless steel grades. Typical recycled content is 30%.
Manufacturability7
V-57-STA's machinability is poor (20/100, worse than 98% of stainless steel grades); weldability fair (40/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with V-57-STA
Is V-57 easy to machine?
Machine in the solution-treated state where possible; aged material is gummy and work-hardening — use rigid setups, positive-rake carbide or ceramic, low speed (15–25 m/min carbide), heavy feed and flood coolant.
Can V-57 be welded?
GTAW/EBW in the solution-treated condition with matching A-286/V-57 or Ni-base filler, then full solution + age; avoid welding aged material because of strain-age (post-weld) cracking.
Can V-57 be formed, bent or molded?
Cold form, roll-thread or coil springs before aging (solution-treated stock is quite ductile); hot work at 1010–1150 °C and finish above 950 °C to avoid tearing.
What surface finishes work on V-57?
Passivate per ASTM A967 or electropolish; no anodizing — for high-temperature fasteners silver, cadmium-free lubricious coatings or dry-film lubricants are typical.
V-57 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 |
|---|---|---|
| C | ≤ 0.08 | 0.05 |
| Mn | ≤ 0.35 | 0.25 |
| Si | ≤ 0.75 | 0.4 |
| P | ≤ 0.03 | — |
| S | ≤ 0.03 | — |
| Cr | 13 – 16 | 14.8 |
| Ni | 25.5 – 28.5 | 27 |
| Mo | 1 – 1.5 | 1.25 |
| Tiγ′ Ni₃(Ti,Al) former | 2.7 – 3.2 | 3 |
| Vvanadium addition distinguishing V-57 from A-286 | 0.1 – 0.5 | 0.3 |
| Al | ≤ 0.35 | 0.25 |
| Bgrain-boundary strengthener | 0.01 | 0.01 |
| Febalance, ~52 % | balance | — |
V-57-STA — frequently asked
What is V-57-STA used for?
V-57-STA is typically used for aerospace fasteners, turbine engine hardware and high-strength bolting. In short: higher-strength A-286 type; 650 °C aerospace fastener alloy; age-hardened iron-base superalloy.
What is the yield strength of V-57-STA?
V-57-STA has a typical yield strength of 725 MPa (105 ksi) and a tensile strength of 1,070 MPa (155 ksi) — stronger than 93% of stainless steel grades. Strength varies by condition: see the 4 listed tempers.
Is V-57-STA easy to machine?
Not especially — machinability is rated poor (20/100, worse than 98% of stainless steel grades). Machine in the solution-treated state where possible; aged material is gummy and work-hardening — use rigid setups, positive-rake carbide or ceramic, low speed (15–25 m/min carbide), heavy feed and flood coolant.
Can V-57-STA be welded?
With care — weldability is rated fair (40/100). GTAW/EBW in the solution-treated condition with matching A-286/V-57 or Ni-base filler, then full solution + age; avoid welding aged material because of strain-age (post-weld) cracking.
What surface finishes work on V-57-STA?
Passivate per ASTM A967 or electropolish; no anodizing — for high-temperature fasteners silver, cadmium-free lubricious coatings or dry-film lubricants are typical.
Can V-57-STA be formed, bent or molded?
Cold form, roll-thread or coil springs before aging (solution-treated stock is quite ductile); hot work at 1010–1150 °C and finish above 950 °C to avoid tearing.
What is the maximum service temperature of V-57-STA?
V-57-STA is rated for continuous use to about 650°C (1,202 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between V-57-STA and V-57-ST?
STA is the default condition — standard aerospace bar/forging condition — best balance of strength, ductility and 650 °C creep performance. ST: soft supply condition for cold forming, deep drawing, machining of complex shapes and welding before aging. Yield strength is 725 MPa in STA versus 275 MPa in ST.
Sources
- AMS 5770 — Fe-Ni-Cr precipitation-hardenable alloy bars, forgings and rings — SAE International (2018)
- ASTM A638/A638M — Precipitation Hardening Iron Base Superalloy Bars, Forgings and Forging Stock for High-Temperature Service — ASTM (2019)
- ASM Specialty Handbook: Heat-Resistant Materials — ASM International (1997)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels and High-Performance Alloys — ASM International (1990)
- MMPDS-18 (A-286 class Fe-Ni superalloy allowables, used as analogue) — Battelle/FAA (2023)
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.