AMS 5895 vs AMS 5891 Round Bar: Key Differences

Using the wrong alloy round bar for a high-heat or high-stress application can result in premature failure, unplanned downtime, and additional cost. AMS 5895 and AMS 5891 are both nickel-based superalloy round bars used in demanding environments, but they are built differently and suited to different conditions. If you are evaluating both grades, this comparison will help you make a clear, informed decision. For anyone specifically sourcing an AMS 5891 Round Bar or an AMS 5895 Round Bar, all the relevant information is covered below.

What is AMS 5891 Round Bar?

AMS 5891 covers a cobalt-nickel-chromium-tungsten alloy bar, most commonly associated with Haynes 188. It is designed to perform well at temperatures up to around 1095°C, with good oxidation resistance and reasonable fabricability. Unlike precipitation-hardened superalloys, it retains useful ductility after prolonged high-temperature exposure.

The AMS 5891 Bar is often preferred where both thermal cycling resistance and weldability are needed together. It is used in the annealed condition and does not require complicated heat treatment to develop its properties.

AMS 5891 Bar specifications usually include chemical composition, mechanical properties, dimensional tolerances, available sizes and testing requirements to provide for reliable performance in aerospace and industrial applications at high temperatures. For complete technical details, refer to AMS 5891 Bar Specifications.

If you are looking for an AMS 5891 Round Bar Supplier, confirm they can provide mill test reports and AMS specification certification with every order.

AMS 5895 Round Bar Overview

AMS 5895 covers a nickel-chromium alloy bar, typically associated with Haynes 230. It contains chromium, tungsten and molybdenum which help with high temperature strength and oxidation resistance. The alloy is especially noted for its resistance to coarsening of the grain, which means it retains its microstructure well after long service at elevated temperatures. It can operate at temperatures up to 1150°C in steady state.

Chemical Composition Comparison

Element	AMS 5891 (Haynes 188)	AMS 5895 (Haynes 230)
Nickel (Ni)	~22%	Balance (~57%)
Cobalt (Co)	Balance (~37%)	5% max
Chromium (Cr)	~22%	~22%
Tungsten (W)	~14%	~14%
Molybdenum (Mo)	None	~2%
Iron (Fe)	3% max	3% max
Carbon (C)	~0.10%	~0.10%

The most significant difference is the base metal. AMS 5891 is primarily cobalt-based with nickel added. AMS 5895 is nickel-based with minimal cobalt. This difference directly affects cost, density, and long-term thermal behaviour.

Mechanical Properties Comparison

Property	AMS 5891	AMS 5895
Tensile Strength (Room Temp)	~960 MPa	~870 MPa
Yield Strength (0.2% offset)	~485 MPa	~380 MPa
Elongation	~50%	~48%
Max Service Temperature	~1095°C	~1150°C

AMS 5891 has higher room-temperature strength. AMS 5895 can sustain performance at slightly higher maximum temperatures and is more stable over long service durations.

Key Differences Between AMS 5895 and AMS 5891

• Base Metal: AMS 5891 is cobalt-based, AMS 5895 is nickel-based.
• Room temperature strength: AMS 5891 has higher yield and tensile strength.
• Max service temperature: AMS 5895 is a little higher temperature (~1150°C vs 1095°C).
• Microstructure Stability: AMS 5895 exhibits better resistance to grain coarsening under long service hours.
• Cobalt content: AMS 5891 has ~37% cobalt; AMS 5895 has 5% or less, so AMS 5895 is typically more cost-effective.
• Thermal cycling: Good AMS 5891 performance in applications with cyclic temperatures.
• Weldability: AMS 5891 is easier to weld and fabricate generally.

Applications of AMS 5891 Round Bar

AMS 5891 Round Bar is designed for applications demanding good mechanical strength and oxidation resistance, particularly under cyclic thermal exposure.

• Aerospace Components: Used in combustion liners and transition ducts in jet engine components. The alloy can survive multiple thermal cycles in aircraft engines without losing its structural integrity.
• Heat Exchangers: AMS 5891 bar is used for tube supports and structural components in high temperature heat exchanger systems above 800°C where its resistance to oxidation extends service life.
• Chemical Processing: Suitable for reactor internals and supports in chemical plants where high temperature and aggressive atmospheres are experienced simultaneously.
• Marine Industry: Used in specialised marine applications involving high heat, such as exhaust system components. A qualified AMS 5891 Round Bar Supplier will provide the documentation and traceability that marine procurement typically requires.

AMS 5895 Round Bar Applications

AMS 5895 is preferred where components need to maintain their properties over long periods at high temperatures rather than cycling repeatedly.

• High Temperature Environments: Good for parts that are continuously exposed to high temperatures, not parts that are exposed to temperature cycling frequently.
• Gas Turbines: Combustor components and structural ring sections for industrial gas turbines. After thousands of hours at operating temperature, it still retains its properties.
• Furnace Components: Furnace fixtures, supports, and retorts use AMS 5895 because it resists both oxidation and grain growth in continuous high-temperature atmospheres.

How to Choose Between AMS 5895 and AMS 5891?

If your application runs above 1100°C continuously, AMS 5895 is the more suitable choice. If you need higher room-temperature strength or your components experience frequent thermal cycling, AMS 5891 is worth considering.

On cost, AMS 5895 is generally less expensive because it contains far less cobalt. Cobalt pricing is volatile, and AMS 5891’s high cobalt content makes it more sensitive to market changes.

Availability should also be checked. AMS 5891 is widely specified in aerospace, so it tends to be more readily stocked by aerospace-approved suppliers. Confirm size availability with your supplier before finalising the specification.

Where to Buy AMS 5891 Round Bar?

Three of the main things to look out for when buying from an AMS 5891 Round Bar Supplier are certification, documentation and ability to supply custom sizes. The supplier should be ISO 9001:2015 certified and provide complete material test reports, heat numbers and chemical composition reports with each order.

Parag Metals is an ISO 9001:2015 Certified exporter of high quality Nickel & Cobalt Alloy round bars and various other grades of round bars. All our orders go through rigorous quality checks. We have standard and custom sizes. If you have a specific requirement then contact Parag Metals with your size and quantity and the team will get back to you with the availability and pricing.

Conclusion

AMS 5891 and AMS 5895 are suitable for different purposes. AMS 5891 has better room temperature strength and resistance to thermal cycling. AMS 5895 is more cost-effective than AMS 5890 due to the lower content of cobalt. It is better for long-duration, high-temperature service. Select as appropriate for your temperature range, load requirements and budget. For immediate response to your query on AMS 5891 Round Bar or AMS 5895 Round Bar, contact Parag Metals.