Hastelloy G-35

About Hastelloy G-35

Name and Equivalent Name: Hastelloy G-35 is identified under the UNS number N06035 and corresponds to DIN/EN 2.4643. It meets ASTM B582, AMS 5936, and NACE MR0175 standards. It is also known as Alloy G-35, reflecting its high nickel and chromium content optimized for corrosion resistance.

Hastelloy G-35 Basic Introduction

Hastelloy G-35 is a high-performance superalloy designed to withstand aggressive environments, especially in the chemical industry. Its composition offers exceptional resistance to wet process phosphoric acid and other highly corrosive media, making it a preferred choice for chemical reactors and piping systems.

Hastelloy G-35 maintains structural integrity at elevated temperatures with excellent thermal stability and high cyclic fatigue resistance. Its ability to perform reliably under stress and prevent corrosion ensures a long service life, even in the harshest environments.

Alternative Superalloys of Hastelloy G-35

Alternatives to Hastelloy G-35 include Hastelloy G-30, which offers similar corrosion resistance but slightly different mechanical properties. Inconel 625 is another option for high-temperature strength. Alloy 20 performs well in sulfuric acid environments, and Monel 400 is ideal for marine applications due to its excellent corrosion resistance in seawater.

Hastelloy G-35 Design Intention

Hastelloy G-35 was developed to enhance corrosion resistance in aggressive chemical environments, particularly in applications handling phosphoric acid. Its unique combination of nickel, chromium, and molybdenum ensures durability against pitting, crevice corrosion, and stress corrosion cracking.

The alloy is intended for use in environments with prevalent thermal cycling and mechanical stress. Its high thermal fatigue resistance suits critical components exposed to high temperatures and fluctuating loads.

Hastelloy G-35 Chemical Composition

The alloy’s optimized chemical composition highly resists corrosion and mechanical stress.

Hastelloy G-35 Physical Properties

Hastelloy G-35 demonstrates physical solid properties, enhancing its performance in harsh conditions.

Metallographic Structure of Hastelloy G-35 Superalloy

Hastelloy G-35 exhibits a face-centered cubic (FCC) structure, providing high ductility and mechanical stress resistance. The alloy's microstructure ensures uniform distribution of molybdenum and chromium, which enhances corrosion resistance in acidic environments.

The alloy’s low carbon content minimizes the formation of carbides at grain boundaries, preventing intergranular corrosion. This stability is essential for maintaining performance in welded and high-temperature applications, ensuring long-term reliability.

Hastelloy G-35 Mechanical Properties

The mechanical properties of Hastelloy G-35 make it ideal for demanding applications.

Key Features of Hastelloy G-35 Superalloy

1. Exceptional Corrosion Resistance

Hastelloy G-35 offers superior resistance to wet-process phosphoric acid and other aggressive chemicals, making it suitable for chemical reactors and piping systems.

2. High Mechanical Strength

The alloy's 690-725 MPa tensile strength ensures durability under high-stress conditions, supporting chemical processing and energy applications.

3. Thermal Stability

Hastelloy G-35 maintains its mechanical properties at temperatures up to 700°C, making it ideal for components exposed to thermal stress and cyclic loading.

4. Resistance to Cyclic Fatigue

The alloy is designed to perform reliably under cyclic fatigue conditions, ensuring structural integrity in reactors and heat exchangers subjected to fluctuating stress.

5. Long Service Life

Hastelloy G-35 resists pitting, crevice corrosion, and stress corrosion cracking, reducing maintenance requirements and ensuring long-term performance in harsh environments.

Hastelloy G-35 Superalloy’s Machinability

Vacuum Investment Casting: Hastelloy G-35 is not ideal for Vacuum Investment Casting due to its lower castability and high chromium content, which can complicate precise molding in a vacuum environment.

Single Crystal Casting: Hastelloy G-35 is unsuitable for Single Crystal Casting because it lacks the required crystallographic alignment for high-stress, creep-resistant applications like turbine blades.

Equiaxed Crystal Casting: While Equiaxed Crystal Casting is technically feasible, Hastelloy G-35’s primary advantage lies in corrosion resistance rather than mechanical strength, limiting its application in this process.

Directional Casting: Hastelloy G-35 performs poorly in Superalloy Directional Casting due to insufficient creep resistance under extreme thermal gradients.

Powder Metallurgy Turbine Disc: The alloy is not typically used for Powder Metallurgy Turbine Disc production as it lacks the necessary mechanical properties for high-stress turbine components.

Precision Forging: Hastelloy G-35 can be used in Superalloy Precision Forging to produce durable, corrosion-resistant components for chemical and industrial applications.

Superalloy 3D Printing: Superalloy 3D Printing with Hastelloy G-35 is viable for customized parts exposed to corrosive environments, such as chemical reactors and heat exchangers.

CNC Machining: Hastelloy G-35 is compatible with CNC Machining, although it requires specialized tooling to prevent work hardening and ensure a smooth surface finish.

Superalloy Welding: Hastelloy G-35 performs well in Superalloy Welding, with low carbon content minimizing carbide precipitation, making it ideal for corrosive environments.

Hot Isostatic Pressing (HIP): Hot Isostatic Pressing (HIP) enhances the structural integrity of Hastelloy G-35 by eliminating internal porosity and improving mechanical properties.

Hastelloy G-35 Superalloy Applications

Aerospace and Aviation: In Aerospace and Aviation, Hastelloy G-35 is used for exhaust systems and chemical processing units, offering durability under corrosive and high-temperature conditions.

Power Generation: Hastelloy G-35 is employed in Power Generation for heat exchangers and scrubbers, providing corrosion resistance against aggressive chemicals.

Oil and Gas: The alloy plays a key role in Oil and Gas equipment such as pipelines, reactors, and valves exposed to harsh chemical environments.

Energy: Hastelloy G-35 is effective in Energy applications, including chemical storage tanks and reactors, where high corrosion resistance is essential.

Marine: Hastelloy G-35 is used in Marine environments, ensuring durability for desalination plants and other equipment exposed to seawater.

Mining: In Mining, Hastelloy G-35 provides corrosion-resistant components for chemical extractors and equipment operating under extreme environmental conditions.

Automotive: Hastelloy G-35 supports Automotive industries by providing corrosion-resistant components for exhaust systems and other parts exposed to harsh environments.

Chemical Processing: In chemical processing, the alloy ensures durability and performance in reactors and heat exchangers that handle aggressive chemicals like wet phosphoric acid.

Pharmaceutical and Food: Hastelloy G-35 meets hygiene standards in the Pharmaceutical and Food industry, offering corrosion-resistant components for reactors and mixers.

Military and Defense: In Military and Defense, the alloy provides reliability in chemical handling systems and storage units exposed to extreme environments.

Nuclear: Hastelloy G-35 finds application in Nuclear reactors, offering long-term durability and corrosion resistance under high temperatures.

When to Choose Hastelloy G-35 Superalloy

Custom superalloy parts made from Hastelloy G-35 are ideal for applications requiring corrosion resistance, mechanical strength, and thermal stability. Its ability to resist aggressive chemicals makes it well-suited for chemical reactors, heat exchangers, and scrubbers in the chemical and power generation industries.

Hastelloy G-35 should be chosen for operations with frequent thermal cycling, as it offers excellent fatigue resistance and maintains structural integrity under varying temperatures. This alloy ensures a long service life with minimal maintenance, especially in environments exposed to wet phosphoric acid, seawater, or corrosive gases.