Cobalt-Chrome Alloy L605 · heat-treated state
Cobalt-Chrome Alloy L605 Stress Relieved
Properties of the Stress Relieved condition, compared with the other L605 tempers.
Use to relax residual stress in welded, cold-formed or additively built parts while keeping most of the strength.
What is L605 Stress Relieved?
L605 Stress Relieved is L605 heat treated to Stress Relieved — use to relax residual stress in welded, cold-formed or additively built parts while keeping most of the strength. L605 Stress Relieved has a yield strength of 570 MPa (82.7 ksi) and a tensile strength of 1,030 MPa (149 ksi) — weaker than 52% of cobalt-chrome alloy grades. Elongation at break is 32% and the elastic modulus is 225 GPa (32.6 Msi). L605 Stress Relieved has a density of 9.13 g/cm³ (0.33 lb/in³), heavier than 98% of cobalt-chrome alloy grades. It melts at 1,329°C (2,424 °F). Solution Annealed is the default condition FabDigit quotes; Stress Relieved is available on request or by drawing note.
Advantages
- Forms and bends easily — 60/100, better than 95% of cobalt-chrome alloy grades
- Readily welded — 72/100, better than 93% of cobalt-chrome alloy grades
- High service temperature — 950°C (1,742 °F), better than 90% of cobalt-chrome alloy grades
- Ductile — tolerates forming and impact — 32%, better than 86% of cobalt-chrome alloy grades
Limitations
- Poor heat conductor — 9.4 W/m·K (5.43 BTU/hr·ft·°F), worse than 100% of cobalt-chrome alloy grades
- High embodied carbon — 19 kg CO₂/kg, worse than 95% of cobalt-chrome alloy grades
L605 Stress Relieved properties
Typical room-temperature values for L605 Stress Relieved — 9 properties are specific to this condition; the rest are grade-level values shared by every L605 temper. Each bar shows where the value sits among the cobalt-chrome alloy grades in FabDigit's library — further right is higher.
Physical3
L605 Stress Relieved has a density of 9.13 g/cm³ (0.33 lb/in³), heavier than 98% of cobalt-chrome alloy grades. It melts at 1,329°C (2,424 °F).
Mechanical14
L605 Stress Relieved has a yield strength of 570 MPa (82.7 ksi) and a tensile strength of 1,030 MPa (149 ksi) — weaker than 52% of cobalt-chrome alloy grades. Elongation at break is 32% and the elastic modulus is 225 GPa (32.6 Msi).
Thermal6
L605 Stress Relieved is rated for continuous service to 950°C (1,742 °F). It conducts heat at 9.4 W/m·K (5.43 BTU/hr·ft·°F), worse than 100% of cobalt-chrome alloy grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
L605 Stress Relieved conducts electricity at 1.9 % IACS, worse than 54% of cobalt-chrome alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 52% of cobalt-chrome alloy grades.
Sustainability4
Producing a kilogram of L605 Stress Relieved takes about 250 MJ of energy and emits 19 kg of CO₂ — more than 91% of cobalt-chrome alloy grades. Typical recycled content is 30%.
Manufacturability8
L605 Stress Relieved's machinability is poor (17/100, better than 90% of cobalt-chrome alloy grades); weldability very good (72/100); formability good (60/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other L605 tempers and conditions
L605 is also supplied in 4 other conditions. The full side-by-side table is on the L605 overview.
- Solution AnnealedDefaultStandard mill condition for sheet, plate, bar and tube — maximum ductility and formability, best corrosion and creep behaviour baseline.460 MPa yield · 240 HB
- Cold WorkedPick for high-strength springs, wire, stents and thin-wall tube where strength matters more than ductility.1,250 MPa yield · 42 HRC
- As PrintedBaseline LPBF/SLM condition: fine cellular structure gives high yield strength but reduced ductility and high residual stress — usually heat treated before service.700 MPa yield · 32 HRC
- Stress RelievedUse to relax residual stress in welded, cold-formed or additively built parts while keeping most of the strength.570 MPa yield · 28 HRC
- HIPChoose for AM or cast parts needing closed porosity, homogenised structure and best ductility/fatigue for flight or implant hardware.480 MPa yield · 245 HB
Working with L605 Stress Relieved
Is L605 easy to machine?
Machine like a work-hardening superalloy: rigid setups, positive-rake carbide or ceramic tooling, low speed / heavy feed, flood coolant and no dwelling to avoid glazing and rapid tool wear.
Can L605 be welded?
Readily GTAW/PAW/EB/laser welded with matching L605 filler (AMS 5796); keep heat input low, use clean argon shielding and re-solution anneal heavily restrained or cold-worked joints.
Can L605 be formed, bent or molded?
Cold forms well when annealed but hardens fast — allow generous bend radii, interstage anneals at 1175–1230 °C; hot work at 1150–1230 °C and finish above ~1050 °C.
What surface finishes work on L605?
Not anodizable; use pickling/passivation, electropolishing or fine mechanical polishing (excellent mirror finish for implants), plus aluminide or thermal-barrier coatings for hot-gas parts.
L605 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 |
|---|---|---|
| Cr | 19 – 21 | 20 |
| W | 14 – 16 | 15 |
| Ni | 9 – 11 | 10 |
| Fe | ≤ 3 | 1.5 |
| Mn | 1 – 2 | 1.5 |
| C | 0.05 – 0.15 | 0.1 |
| Si | ≤ 0.4 | 0.2 |
| P | ≤ 0.04 | — |
| S | ≤ 0.03 | — |
| Cobalance, nominally ~51 % | balance | — |
L605 Stress Relieved — frequently asked
What is L605 Stress Relieved used for?
L605 Stress Relieved is typically used for combustion liners and transition ducts, turbine and exhaust valves, hot-gas ducting and seals, high-temperature springs, afterburner and nozzle components and surgical implants and stents. In short: aerospace high-temp cobalt.
What is the yield strength of L605 Stress Relieved?
L605 Stress Relieved has a typical yield strength of 570 MPa (82.7 ksi) and a tensile strength of 1,030 MPa (149 ksi) — weaker than 52% of cobalt-chrome alloy grades. Strength varies by condition: see the 5 listed tempers.
Is L605 Stress Relieved easy to machine?
Not especially — machinability is rated poor (17/100, better than 90% of cobalt-chrome alloy grades). Machine like a work-hardening superalloy: rigid setups, positive-rake carbide or ceramic tooling, low speed / heavy feed, flood coolant and no dwelling to avoid glazing and rapid tool wear.
Can L605 Stress Relieved be welded?
Yes — weldability is rated very good (72/100). Readily GTAW/PAW/EB/laser welded with matching L605 filler (AMS 5796); keep heat input low, use clean argon shielding and re-solution anneal heavily restrained or cold-worked joints.
What surface finishes work on L605 Stress Relieved?
Not anodizable; use pickling/passivation, electropolishing or fine mechanical polishing (excellent mirror finish for implants), plus aluminide or thermal-barrier coatings for hot-gas parts.
Can L605 Stress Relieved be formed, bent or molded?
Cold forms well when annealed but hardens fast — allow generous bend radii, interstage anneals at 1175–1230 °C; hot work at 1150–1230 °C and finish above ~1050 °C.
What is the maximum service temperature of L605 Stress Relieved?
L605 Stress Relieved is rated for continuous use to about 950°C (1,742 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between L605 Solution Annealed and L605-HIP?
Solution Annealed is the default condition — standard mill condition for sheet, plate, bar and tube — maximum ductility and formability, best corrosion and creep behaviour baseline. HIP: choose for AM or cast parts needing closed porosity, homogenised structure and best ductility/fatigue for flight or implant hardware. Yield strength is 460 MPa in Solution Annealed versus 480 MPa in HIP.
Can FabDigit make parts in L605 Stress Relieved?
Yes — L605 Stress Relieved is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- AMS 5537 — Cobalt Alloy Sheet, Strip and Plate (UNS R30605) — SAE International (2020)
- AMS 5759 — Cobalt Alloy Bars, Forgings and Rings (UNS R30605) — SAE International (2019)
- ASTM F90 — Wrought Co-20Cr-15W-10Ni Alloy for Surgical Implant Applications — ASTM International (2021)
- HAYNES 25 alloy technical data — Haynes International (2020)
- ASM Handbook Vol.1 & Vol.2 — Superalloys / Cobalt-base alloys — ASM International (1990)
- Additive manufacturing (LPBF) L605 mechanical property compilations — peer-reviewed AM literature / powder producer datasheets (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.