ThePipingMart Blog Grades HAYNES 188 Alloy (UNS R330188) – Composition, Properties and Uses

HAYNES 188 Alloy (UNS R330188) – Composition, Properties and Uses

Haynes 188 Alloy

UNS R330188 is an alloy that has a wide variety of applications in many industries, from aerospace to medical. It is a nickel-based superalloy with excellent oxidation resistance, strength, and thermal stability. Thanks to its unique properties, Haynes 188 is used for a variety of applications such as aircraft components, heat exchangers, turbine blades, and more. Let’s take a closer look at the composition, mechanical properties, physical properties, uses, and corrosion resistance of this remarkable alloy.

Haynes 188 Alloy Composition

The composition of UNS R330188 includes iron (Fe), cobalt (Co), chromium (Cr), manganese (Mn), molybdenum (Mo), niobium (Nb), tungsten (W), tantalum (Ta) and yttrium (Y). The percentages vary depending on the application but typically range from 20-30% Cr; 10-25% Co; 2-4% Mn; 4-7% Mo; 1-3% Nb; 1-2%; Ta; 1-2%; W; 0.1-0.5%; Y and balance Fe.

Element Content (%)
Cobalt, Co ≥ 37
Nickel, Ni 22
Chromium, Cr 22
Tungsten, W 14
Iron, Fe ≤ 3
Manganese, Mn ≤ 1.25
Silicon, Si ≤ 0.50
Carbon, C ≤ 0.15
Lanthanum, La 0.040
Phosphorous, P 0.020
Sulfur, S 0.015

Haynes 188 Mechanical Properties

This alloy has superior strength even at elevated temperatures due to its high levels of nickel and cobalt content. It also has good ductility and can be formed into complex shapes with ease. Additionally, it has excellent fatigue strength, which makes it suitable for use in parts that are subject to repeated stress or vibration, such as those found in aircraft engines or gas turbines. Its fatigue limit is around 250 MPa when tested at room temperature or higher temperatures up to 600 °C.

Haynes 188 Physical Properties

UNS R330188 has an impressive melting point of 1350 °C which makes it suitable for applications where high temperatures are regularly encountered, such as in turbine blades or exhaust systems. It also has excellent thermal stability with good oxidation resistance up to 1000 °C in air environments without any protective coating required. Additionally, it has low magnetic permeability making it suitable for use in sensitive electronic equipment where magnetic fields may interfere with operation or performance.

Properties Metric Imperial
Density 8.9 g/cm3 0.324 lb/in3
Melting point 1330°C 2425°F

Haynes 188 Uses

Due to its unique combination of properties such as strength, thermal stability, corrosion resistance and oxidation resistance, this alloy is well suited for use in a wide variety of applications, including aircraft components such as turbine blades or exhaust systems; heat exchangers used in chemical processing plants; engine components used in the automotive industry; medical implants such as hip replacements due to its biocompatibility; nuclear power plant components due to its radiation resistance etc.

Haynes 188 Equivalent

  • AMS 5608
  • AMS 5772
  • GE B50A712
  • GE B50TF74
  • GE B50TF74A
  • PWA 1042

Haynes 188 Corrosion Resistance

This alloy offers good corrosion resistance even in harsh environments thanks to its high chromium content, which provides superior protection against rusting or other forms of metal degradation caused by exposure to water or air-containing oxygen molecules over time. Additionally, it provides excellent protection against chloride ion attack, making it suitable for use near salt water where other materials may not be able to withstand the corrosive effects of seawater over time without special coatings or treatments applied beforehand.


In conclusion, Haynes 188 is an incredibly versatile alloy with a wide range of uses across many industries, from aerospace engineering to medical devices, due to its superior strength even at elevated temperatures coupled with excellent oxidation resistance and corrosion protection capabilities even under harsh conditions like near saltwater environments without any additional coatings required beforehand making it an ideal material choice for numerous applications requiring reliable, long-lasting performance without fail over extended periods of time under extreme operating conditions making it well worth considering if you are looking for a reliable solution that can stand up to the test every time!

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