Incoloy 800, Incoloy 800H and Incoloy 800HT belong to the same high-temperature nickel-iron-chromium alloy family, but they are not interchangeable in every engineering application.

The differences become particularly important when designing heat exchangers, industrial furnaces, petrochemical equipment and high-temperature process systems.

What Is Incoloy 800?

Incoloy 800 is a nickel-iron-chromium alloy developed for high-temperature applications.

Its balanced chemistry provides:

• Oxidation resistance
• Carburization resistance
• Nitridation resistance
• Good mechanical properties
• Resistance to high-temperature corrosion

It is frequently used in heat-treatment and industrial heating environments.

What Is Incoloy 800H?

Incoloy 800H is a modified version of Alloy 800 designed for improved high-temperature creep and rupture performance.

The higher-temperature mechanical requirements make 800H attractive for pressure-containing components operating at elevated temperatures.

What Is Incoloy 800HT?

Incoloy 800HT is further optimized for high-temperature structural performance.

It is commonly considered when long-term creep resistance and elevated-temperature strength are major design requirements.

800 vs 800H vs 800HT

The simplest way to understand the three grades is:

Incoloy 800: general high-temperature service.

Incoloy 800H: improved high-temperature creep and rupture performance.

Incoloy 800HT: optimized for demanding elevated-temperature mechanical performance.

The actual selection must still follow the applicable specification and engineering design requirements.

Typical Applications

Industrial Furnaces

These alloys can be used for furnace components exposed to high temperatures and oxidizing atmospheres.

Heat Exchangers

High-temperature heat-transfer equipment may require resistance to oxidation, carburization and thermal cycling.

Petrochemical Processing

Hydrocarbon processing equipment may experience elevated temperatures combined with carburizing or other aggressive environments.

Power Generation

Selected high-temperature piping and components can require nickel-iron-chromium alloys for improved long-term reliability.

Why Is Nickel Important?

Nickel provides a stable matrix capable of retaining useful properties at elevated temperatures.

Chromium improves oxidation and corrosion resistance, while iron contributes to the overall alloy structure and economics.

The controlled combination allows these alloys to operate in environments where conventional steels may not provide adequate performance.

How Should Buyers Select Between 800, 800H and 800HT?

Consider:

• Design temperature
• Stress level
• Service duration
• Creep requirements
• Pressure
• Atmosphere
• Product form
• Applicable specification

If the application is primarily corrosion and oxidation related, Alloy 800 may be appropriate.

If long-term high-temperature mechanical performance is critical, 800H or 800HT may be more suitable.

Purchasing Checklist

When requesting a quotation, provide:

• Grade
• Standard
• Product type
• OD / ID or thickness
• Length
• Quantity
• Heat-treatment condition
• Inspection requirements
• Delivery requirements

This information allows the supplier to identify the correct material condition.

Conclusion

Incoloy 800, 800H and 800HT are closely related alloys, but their high-temperature mechanical performance and intended service conditions differ.

Understanding these differences can help engineers avoid both over-specification and under-specification.

AlloysFactory supplies Incoloy products including 800, 800H, 800HT, 825 and 925 in multiple product forms and can support customized specifications.

Company: Danyang Jiaxin New Materials Technology Co., Ltd.
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