A Complete Guide to Incoloy 925 Plates

Incoloy 925 plates are a high-performance nickel-based alloy product widely used in demanding industrial applications. Known for their superior strength, corrosion resistance, and ability to withstand high temperatures and pressure, these plates have become indispensable in sectors like oil and gas, marine engineering, and chemical processing.

This guide offers a detailed overview of Incoloy 925 plates, including their composition, mechanical properties, manufacturing standards, common applications, and benefits. Whether you are a procurement specialist or an engineer, this article will help you understand why Incoloy 925 plates are a strategic material choice for your projects.

What Is Incoloy 925?

Incoloy 925 is a precipitation-hardenable nickel-iron-chromium alloy with additions of molybdenum, copper, and titanium. This unique combination gives the alloy excellent corrosion resistance and high strength. It is especially resistant to stress corrosion cracking, pitting, and crevice corrosion in aggressive environments.

Incoloy 925 is designated under UNS N09925 and often produced according to ASTM B805 specifications.

Chemical Composition of Incoloy 925 Plates

The typical chemical composition of Incoloy 925 plates is as follows:

• Nickel (Ni): 42-46%

• Chromium (Cr): 19.5-23.5%

• Iron (Fe): Balance

• Molybdenum (Mo): 2.5-3.5%

• Copper (Cu): 1.5-3.0%

• Titanium (Ti): 1.9-2.4%

• Aluminum (Al): ≤ 0.2%

• Manganese (Mn): ≤ 1.0%

• Carbon (C): ≤ 0.03%

• Sulfur (S): ≤ 0.01%

This carefully balanced chemistry enables the alloy to perform in chloride-containing and acidic environments where standard stainless steels would fail.

Mechanical Properties

Incoloy 925 plates offer impressive mechanical properties, especially after aging heat treatment. The following are typical values:

• Tensile Strength: ≥ 760 MPa

• Yield Strength (0.2% offset): ≥ 450 MPa

• Elongation: ≥ 30%

• Hardness: Approx. 180-240 HB

These properties make it ideal for components subjected to high stress, pressure, and mechanical wear.

Key Features and Advantages

1. Corrosion Resistance

One of the most important characteristics of Incoloy 925 plates is their exceptional corrosion resistance. The alloy resists:

• Sulfide stress cracking

• Pitting and crevice corrosion

• Oxidation and scaling at elevated temperatures

• Chloride-ion attack in seawater and brine solutions

2. High Strength and Toughness

The alloy is strengthened by precipitation hardening, giving it superior load-bearing capability compared to austenitic stainless steels.

3. Thermal Stability

Incoloy 925 maintains its integrity under fluctuating temperatures, making it ideal for applications involving thermal cycling.

4. Excellent Weldability and Fabrication

Despite its strength, Incoloy 925 plates can be welded and formed using conventional techniques, making them practical for manufacturing and repairs.

Common Applications of Incoloy 925 Plates

The durability and performance of Incoloy 925 make it suitable for a wide range of industries:

● Oil and Gas Industry

Used in downhole and surface gas-well components, tubing, and hangers due to its resistance to sulfide stress cracking.

● Chemical Processing

Incoloy 925 plates are used in heat exchangers, pressure vessels, and chemical reactor linings exposed to acids, chlorides, and aggressive media.

● Marine Engineering

Its resistance to seawater corrosion makes it ideal for marine hardware and offshore platform components.

● Pollution Control Equipment

Used in systems dealing with flue gases, acids, and chemical by-products.

● Nuclear and Power Generation

Valued for structural components in high-temperature and corrosive environments in power plants.

Manufacturing Standards

Incoloy 925 plates are typically manufactured according to international standards to ensure quality and performance:

• ASTM B805 – Standard Specification for Wrought Nickel-Iron-Chromium-Molybdenum-Copper Alloys (UNS N09925)

• ASME Code Compliance – Required for pressure vessel and boiler applications

• EN and ISO Standards – European equivalents for global compatibility

Manufacturers like sasaalloy ensure strict compliance with these standards, offering traceability and material certifications for every batch.

Surface Finishes and Thickness Range

Incoloy 925 plates are available in various surface finishes to suit specific applications:

• Hot rolled (HR)

• Cold rolled (CR)

• Pickled

• Polished

• Brushed

Typical thickness ranges from 3 mm to 100 mm or more, depending on project requirements.

Fabrication and Machinability

Although Incoloy 925 is a high-strength alloy, it remains relatively machinable with high-speed steel or carbide tools. Proper coolant use and slow feed rates are recommended to ensure smooth cuts and avoid tool wear.

It can be welded using:

• Gas tungsten arc welding (GTAW)

• Gas metal arc welding (GMAW)

• Shielded metal arc welding (SMAW)

Welded structures maintain corrosion resistance and mechanical strength with proper post-weld heat treatment.

Stock and Availability

sasaalloy maintains a comprehensive inventory of Incoloy 925 plates in various dimensions, ready for immediate delivery. Custom-cut sizes and surface treatments are also available on request.

With a global supply network and strong production capability, sasaalloy can meet both standard and urgent demands for nickel alloy plates.

Comparison with Other Alloys