L605 (Haynes® 25) Cobalt Alloy
L605 (Haynes® 25) Cobalt Alloy 〞 Machinability, Welding Constraints, and Intermediate-Temperature Embrittlement
For gas turbine combustor, high-temperature bearing, and medical implant engineers and buyers 〞 supplied by ZYTC Alloy, China-based cobalt alloy manufacturer and exporter, ISO 9001 certified
"Strongest Machinable Cobalt Alloy" 〞 What It Actually Means
L605 (UNS R30605) offers a leading strength-to-fabricability balance among cobalt alloys that can be cold formed, machined, and welded. Continuous service reaches 1800∼F (982∼C).
But L605's strength comes from cold-work hardening, not age precipitation. Solution-annealed yield is ~470 MPa, tensile ~995 MPa, hardness ~HRC 24. At 25% cold work, yield rises to ~1270 MPa, tensile ~1605 MPa, hardness HRC 44.
Procurement action: State the condition on the PO 〞 solution annealed, or cold-worked with reduction/hardness range. If the certificate says only "L605," you cannot confirm design strength.
Intermediate-Temperature Exposure: Room-Temperature Ductility Drops
After prolonged service at 600每800∼C, L605 〞 like X alloy or 625 〞 loses room-temperature ductility. If the component later requires room-temperature disassembly, repair, or machining, it may have lost the ductility it had at delivery.
Procurement action: For components involving room-temperature operations after long-term intermediate-temperature service, require room-temperature ductility data after exposure, or account for this constraint in design.
Welding: SAW Not Recommended, Cooling Rate Critical
GTAW, GMAW, shielded metal arc, electron beam, and resistance welding are all suitable. Submerged arc welding (SAW) is not recommended 〞 high heat input plus slow cooling increase restraint and promote cracking.
Practice requirements: good joint fit-up, minimum restraint, low interpass temperature, rapid cooling after welding.
Post-weld heat treatment: Generally not required. For maximum ductility, solution anneal at 2150每2250∼F (1170每1230∼C) and rapid cool. Treatment below the solution temperature causes carbide precipitation and degrades properties.
Procurement action: Specify SAW prohibited, interpass temperature limit, and whether post-weld solution annealing is required.
Oxidation and Corrosion: 1900∼F Ceiling, Acid Resistance Has Conditions
L605 maintains good oxidation resistance to 1900∼F (1038∼C) with excellent sulfidation resistance. It resists hydrochloric acid, nitric acid, and wet chlorine 〞 but "use with caution at certain concentrations and temperatures." L605 is not designed for aqueous corrosion service; acid resistance is supplementary, not a primary design basis.
Procurement action: For acid media, provide concentration, temperature, and oxidizing/reducing conditions before quoting.
Chemical Composition (UNS R30605)
| Element | Content (wt%) |
|---|---|
| Co | Balance |
| Cr | 19.0 每 21.0 |
| W | 14.0 每 16.0 |
| Ni | 9.0 每 11.0 |
| Mn | 1.0 每 2.0 |
| Fe | ≒ 3.0 |
| C | 0.05 每 0.15 |
| Si | ≒ 0.40 |
Supply Specifications
| Item | Parameter |
|---|---|
| Standard | UNS R30605 / ASTM F90 (medical) / AMS 5537 (sheet) / AMS 5759 (bar) |
| Form | Round bar, sheet, strip, plate, custom forgings |
| Condition | Solution annealed (standard); cold-worked by agreement |
| Certificate | EN 10204 3.1, with measured chemistry and mechanical properties |
Applications
Gas turbines: Combustor and afterburner components.
High-temperature bearings: Ball bearings and races 〞 cold-worked condition for hardness and wear resistance.
Springs: High-temperature strength and relaxation resistance.
Heart valves: Biocompatibility and body-fluid corrosion resistance (ASTM F90).
Why ZYTC Alloy
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Condition stated explicitly: Annealed or cold-worked condition on the certificate, with measured hardness or reduction.
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Welding coordination: Incoming condition matched to welding process before quoting; SAW limitation flagged.
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Medical-grade option: ASTM F90 compliant material available.
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China-based manufacturer and exporter: Direct mill supply, full traceability.
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Certification: ISO 9001; EN 10204 3.1; third-party testing available.
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Lead time: Standard sizes 7每10 days; non-standard or tested orders 3每4 weeks; FOB.
Request a Quote
Please provide: form, size, target condition (annealed / cold-worked with hardness or strength), whether welding is involved, service temperature and medium, quantity, and whether ASTM F90 or third-party testing is required.
If welding or long-term intermediate-temperature service is involved, note this 〞 we will confirm condition and process compatibility before quoting.
📧 dominic@zytc-steel.com
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