Haynes 188, UNS R30188, is a cobalt based superalloy strengthened by tungsten and stabilized by a lanthanum addition that improves oxide adherence. It resists oxidation and sulfidation at extreme temperature and keeps strength where nickel alloys begin to fade.
It is a combustor, transition duct and afterburner material and is also used in high temperature bellows and seal hardware.
Stocked as sheet, plate, bar and forgings in the solution annealed condition.
Sizes and stock
- Round bar: up to 7" DIA
- Sheet / plate: up to 2" THK
- Forgings and flat bar: by request
Processing capabilities
- Billet conversion and open die, closed die and ring forging
- Solution treat, age and anneal to the applicable spec
- Saw cutting, trepanning, gun drilling and CNC machining
- Ultrasonic, penetrant dye, micrography and physical testing
Specifications
Material is released to the applicable specification with mill test reports and, on request, independent lab verification.
Why engineers specify Haynes 188
- Cobalt base for high temperature strength and sulfidation resistance
- Excellent oxidation resistance to about 2100F
- Very good fabricability and weldability for a superalloy
- Established hot section sheet material
Nominal chemistry
Percent by weight, nominal composition per the governing specification. The mill test report for your heat is the controlling document.
Typical mechanical properties
| Condition | Tensile strength | Yield strength | Elongation | Hardness |
|---|---|---|---|---|
| Solution annealed | 130 ksi min | 65 ksi min | 40% min | - |
Typical published values for reference only, not for design. Properties vary with section size, product form and processing. Order to the specification and condition your drawing requires.
Typical applications
- Combustion chambers and transition ducts
- Afterburner and nozzle hardware
- High temperature bellows and seals
- Industrial heating hardware
Fabrication notes
Machining
Nickel and cobalt superalloys work harden aggressively. Use rigid setups, sharp tooling, slow speeds, positive feed that stays under the hardened skin, and flood coolant. Age hardened material machines far more slowly than solution treated material, so rough before aging wherever the print allows.
Welding
Most solid solution grades weld readily with matching filler. Age hardenable grades such as 718 and Waspaloy are welded in the solution treated condition and aged afterward to control strain age cracking.
Forming
Hot working ranges are narrow and forces are high. Cold form in the annealed condition with intermediate anneals, and stress relieve before final heat treatment.
Haynes 188 compared with similar grades
Haynes 230
Nickel based, excellent stability, generally lower cost.
L-605
Cobalt alloy with similar uses and slightly different oxidation behaviour.
Designations and cross reference
- Material family
- Nickel & Cobalt Alloys
- UNS number
- R30188
- Werkstoff (W.Nr)
- 2.4683
Working from an obsolete, foreign or superseded designation? Send it over and we will cross reference it to a current grade and specification.
Quality, testing and traceability
Supplied with mill test reports and heat traceability, with ultrasonic inspection, penetrant dye, micrography, grain size, stress rupture and mechanical testing available on request.
We are AS9100D and ISO 9001:2015 registered. If our stock does not already carry the inspection your specification requires, we can quote the material with that work performed. More on our quality system
Available forms
Custom sizes converted from billet, plus saw cut, waterjet and near-net blanks. See custom conversions
Haynes 188 frequently asked questions
What is Haynes 188?
Haynes 188, UNS R30188, is a cobalt based superalloy strengthened by tungsten and stabilized by a lanthanum addition that improves oxide adherence. It resists oxidation and sulfidation at extreme temperature and keeps strength where nickel alloys begin to fade.
What forms is Haynes 188 available in?
We supply Haynes 188 in bar, sheet, plate, forging. Custom sizes are converted from billet, and we can provide saw cut, waterjet or near net blanks so material arrives closer to your finished part.
What is the UNS or equivalent designation for Haynes 188?
Haynes 188 is designated UNS R30188, Werkstoff 2.4683. If your drawing calls out an obsolete or foreign designation we can cross reference it and confirm the equivalent before you order.
What specifications can Haynes 188 be supplied to?
Commonly ordered specifications include AMS 5608, AMS 5772, AMS 5807. Material is released to the specification and condition on your purchase order, with mill test reports supplied as standard.
What conditions can Haynes 188 be ordered in?
We can supply Solution annealed. If our stock is not already in the condition you need, we can quote it with the heat treatment performed before shipment.
Can you cut Haynes 188 to size?
Yes. Saw cutting, waterjet, laser and shearing are available, along with trepanning, gun drilling, lathe turning and CNC machining, so you can order blanks or rough machined pieces rather than full lengths.
Do you provide test reports and additional testing on Haynes 188?
Every order ships with mill test reports and heat traceability. If your print calls for ultrasonic inspection, penetrant dye, magnetic particle, chemical assay, micrography, hardness or mechanical testing and our stock does not already carry it, we can quote the material with that work performed.
Can Haynes 188 be supplied to DFARS domestic melt requirements?
Tell us at quote stage if the order is DFARS or domestic melt restricted and we will confirm availability against that requirement before you commit.
What do you need to quote Haynes 188?
Grade, form, dimensions, quantity, specification and condition, plus any testing or certification requirements and the date you need it. Send a drawing if you have one. Quotes are typically ready within 24 hours.
How does Haynes 188 compare with Haynes 230?
Nickel based, excellent stability, generally lower cost.