Udimet 188 Alloy

Udimet 188 (UNS R30188 / W.Nr. 2.4683), also known as Alloy 188, is a cobalt-nickel-chromium-tungsten superalloy designed for extreme high-temperature service. Unlike precipitation-hardened nickel alloys, Udimet 188 derives its strength primarily from solid-solution strengthening by tungsten and carbide strengthening mechanisms.

The alloy offers one of the best combinations of oxidation resistance, thermal fatigue resistance, hot corrosion resistance, and fabricability among cobalt-based superalloys. Its ability to maintain structural integrity at temperatures approaching 1095°C makes it a preferred material for aerospace gas turbine hot-section components and industrial thermal processing systems.

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Udimet 188 At a Glance

Key Attribute	Value
Alloy Name	Udimet 188
UNS Number	R30188
Werkstoff Number	2.4683
Material Type	Cobalt-Nickel-Chromium-Tungsten Superalloy
Strengthening Mechanism	Solid Solution Strengthening
Density	9.14 g/cm³
Melting Range	1315 – 1410°C
Maximum Service Temperature	1095°C
Main Strength	Oxidation & Thermal Fatigue Resistance
Typical Forms	Sheet, Plate, Bar, Wire, Pipe
Main Applications	Combustors, Afterburners, Transition Ducts
Key Standards	AMS 5608, AMS 5772

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Features of Udimet 188

• Exceptional oxidation resistance up to 1095°C
• Excellent hot corrosion resistance
• Outstanding thermal fatigue resistance
• Superior thermal stability during cyclic heating
• Excellent weldability compared with many superalloys
• Good ductility after long-term thermal exposure
• High resistance to sulfidation environments
• Excellent fabrication characteristics
• Strong resistance to combustion gases
• Proven aerospace hot-section performance

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Chemical Composition of Udimet 188

Element	Content (%)
Cobalt (Co)	Balance
Nickel (Ni)	20.0 – 24.0
Chromium (Cr)	20.0 – 24.0
Tungsten (W)	13.0 – 16.0
Iron (Fe)	≤ 3.0
Manganese (Mn)	≤ 1.25
Silicon (Si)	≤ 0.50
Carbon (C)	0.05 – 0.15
Lanthanum (La)	0.02 – 0.12
Boron (B)	≤ 0.015

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Physical Properties of Udimet 188

Property	Value
Density	9.14 g/cm³
Melting Range	1315 – 1410°C
Electrical Resistivity	1.05 μΩ·m
Thermal Conductivity	11.7 W/m·K
Specific Heat Capacity	435 J/kg·K
Modulus of Elasticity	214 GPa

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Mechanical Properties of Udimet 188

Solution Annealed Condition

Property	Metric Value
Tensile Strength	960 MPa
Yield Strength (0.2% Offset)	435 MPa
Elongation	45%
Hardness	HB 220 – 280

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Corrosion Resistance

Udimet 188 exhibits exceptional resistance to oxidation, hot corrosion, sulfidation, and combustion gas attack. The combination of chromium and lanthanum additions promotes the formation of highly protective oxide scales even under severe thermal cycling conditions.

The alloy performs particularly well in:

• Aerospace exhaust systems
• Combustion chambers
• Sulfur-bearing atmospheres
• High-temperature oxidizing environments
• Thermal cycling applications

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High Temperature Performance

One of the primary reasons for selecting Udimet 188 is its ability to maintain structural stability at temperatures approaching 1095°C.

Key benefits include:

• Excellent oxidation resistance to 1095°C
• Outstanding thermal fatigue resistance
• Superior creep resistance at elevated temperatures
• Resistance to thermal shock
• Long-term microstructural stability
• Reliable hot-section turbine performance

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Available Forms

J&A Alloy supplies Udimet 188 in:

• Plate
• Sheet
• Strip
• Round Bar
• Wire
• Pipe
• Tube
• Forgings
• Rings
• Custom Machined Parts

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Applications of Udimet 188

Aerospace

• Combustor liners
• Afterburner components
• Exhaust nozzles
• Transition ducts
• Flame holders

Gas Turbines

• Hot gas path components
• Combustion systems
• Diffuser assemblies

Industrial Furnaces

• High-temperature fixtures
• Heat treatment equipment
• Burner systems

Energy & Power Generation

• Combustion hardware
• Thermal processing equipment

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Udimet 188 vs Other High Temperature Alloys

Alloy	Main Advantage	Service Temperature	Typical Applications
Udimet 188	Oxidation & Thermal Fatigue Resistance	Up to 1095°C	Combustors, Afterburners
Haynes 188	Equivalent Grade	Up to 1095°C	Gas Turbine Hot Sections
Haynes 230	Creep Resistance	Up to 1149°C	Industrial Furnaces
Inconel 625	Corrosion Resistance	Up to 982°C	Chemical Processing

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Welding & Fabrication

Forming

Udimet 188 exhibits excellent forming characteristics and can be cold worked or hot worked using conventional fabrication methods.

Machining

• Use rigid machine setups
• Employ carbide tooling
• Moderate cutting speeds recommended
• Adequate coolant required

Welding

Udimet 188 is regarded as one of the most weldable cobalt-based superalloys and can be welded using:

• GTAW (TIG)
• GMAW (MIG)
• Plasma Arc Welding
• Resistance Welding

Post-weld heat treatment is generally not required.

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Standards & Equivalent Grades

Standard	Designation
UNS	R30188
Werkstoff	2.4683
AMS	AMS 5608
AMS	AMS 5772
Equivalent Grade	Haynes 188

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Frequently Asked Questions

What is Udimet 188?

Udimet 188 is a cobalt-based superalloy designed for extreme high-temperature applications requiring oxidation resistance and thermal fatigue resistance.

Is Udimet 188 the same as Haynes 188?

Yes. Udimet 188 and Haynes 188 refer to the same UNS R30188 cobalt-based alloy.

What is the UNS number of Udimet 188?

UNS R30188.

What temperature can Udimet 188 withstand?

Continuous service temperatures up to approximately 1095°C.

Is Udimet 188 weldable?

Yes. Udimet 188 is one of the most weldable cobalt-based superalloys available.

What is Udimet 188 used for?

Combustors, afterburners, transition ducts, exhaust systems, and gas turbine hot-section components.

Does Udimet 188 resist oxidation?

Yes. It provides exceptional oxidation resistance under severe thermal cycling conditions.

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Why Choose J&A Alloy

Specialized High-Temperature Alloy Supplier

J&A Alloy provides premium nickel and cobalt superalloys for aerospace, energy, petrochemical, and industrial applications worldwide.

Strict Quality Control

• PMI Testing
• Chemical Analysis
• Mechanical Testing
• Ultrasonic Inspection
• Third-Party Inspection Available

Complete Documentation

• EN 10204 3.1
• Mill Test Certificate (MTC)
• Full Traceability Records

Flexible Manufacturing

• Custom Dimensions
• Precision Machining
• Forging Services
• Fast Global Delivery

Global Industry Experience

Trusted supplier for aerospace manufacturers, gas turbine OEMs, industrial furnace builders, and energy companies worldwide.