Hot gas filtration systems operate under extreme conditions where high temperature and corrosive compounds can quickly degrade filter media. Choosing the wrong alloy can lead to early system failure, expensive production suspension, and safety risks. For engineers and plant managers, the challenge lies in balancing corrosion resistance, mechanical strength, and cost without compromising reliability.
Two alloys dominate the conversation: 316 stainless steel and Hastelloy C-22. Both are widely used in woven wire mesh filter elements, yet they serve very different roles. Understanding how each performs under thermal stress and chemical attack is critical to optimizing service life and minimizing maintenance costs.
At W.S. Tyler, our mission is to help you achieve cleaner, safer, and more efficient operations through engineered filtration solutions backed by over 150 years of expertise. By comparing these two alloys, we aim to provide clarity on which material best suits your application, whether you prioritize cost efficiency or maximum corrosion resistance.
In this article, we’ll break down the performance characteristics of 316 Stainless Steel and Hastelloy C-22 in hot gas filtration. You’ll learn the strengths, limitations, and ideal use cases, followed by practical guidance on how to make the right choice for your process.
Understanding Alloy Performance in Hot Gas Filtration
Choosing the right alloy for hot gas filtration is a decision that can make or break system performance. These environments often involve high temperature, corrosive gases, and chemical exposure, all of which accelerate wear and compromise filter integrity. Two materials frequently considered for these conditions are 316 stainless steel and Hastelloy C-22, each offering unique benefits and limitations.
316 stainless steel is an austenitic alloy composed primarily of iron, chromium, nickel, and molybdenum. Its balanced chemistry provides strong resistance to general corrosion and chloride-induced pitting, making it a reliable choice for moderately aggressive environments. However, its performance begins to decline at higher temperatures, and it struggles in highly acidic or mixed chemical conditions.
For applications where heat and chlorides are present but not extreme, 316 stainless steel remains a cost-effective and widely available solution.
Hastelloy C-22, by contrast, is a nickel-based superalloy designed for severe chemical and thermal stress. With a composition rich in nickel, chromium, molybdenum, and tungsten, it offers exceptional resistance to oxidizing and reducing agents, strong acids, and chlorides. This alloy maintains its strength and corrosion resistance at extreme temperatures, making it ideal for filtration systems exposed to aggressive chemical streams and sustained heat.
Its ability to withstand pitting, crevice corrosion, and stress corrosion cracking far surpasses that of stainless steel, ensuring long-term reliability in the harshest environments.
The choice ultimately comes down to balancing performance and cost. Hastelloy C-22 delivers unmatched durability and chemical resistance but at a significantly higher price point. For operations where downtime and contamination risks carry heavy consequences, the investment often pays off. Conversely, in less demanding conditions, 316 stainless steel offers a practical solution without sacrificing quality.
316 Stainless Steel: Strengths and Limitations
316 stainless steel has earned its reputation as one of the most versatile alloys in industrial filtration systems, thanks to its balance of corrosion resistance, mechanical strength, and affordability. Its composition of 16-18% chromium, 10-14% nickel, and 2-3% molybdenum creates a passive oxide layer that protects against rust and general corrosion.
This makes it a reliable choice for environments involving mild acids, chlorides, and moderate heat, such as food processing, pharmaceuticals, and marine applications.
One of its key advantages is resistance to pitting and crevice corrosion in chloride-containing environments, which is enhanced by the molybdenum content. Additionally, 316 stainless steel offers excellent weldability and fabrication ease, allowing for cost-effective manufacturing and maintenance. Its mechanical properties, including high tensile and yield strength, are sufficient for most structural applications where extreme stress is not a factor.
Having difficulty with managing temperature in your hot gas filtration system? Learn about the problems extreme temperatures can cause and the solutions to fix them in our article below:
However, limitations arise under harsh conditions. At temperatures above 600°C (1,110°F), 316 stainless steel begins to lose strength and becomes more susceptible to oxidation and stress corrosion cracking. In highly acidic or mixed chemical environments, such as those involving hydrochloric or sulfuric acid, it cannot match the corrosion resistance of nickel-based alloys like Hastelloy C-22.
While its performance is adequate for moderate conditions, prolonged exposure to aggressive chemicals or sustained high heat can lead to early component failure.
Ultimately, 316 stainless steel is best suited for applications where cost-effectiveness and broad corrosion resistances are priorities, but where the chemical and thermal demands do not exceed its capabilities. For operations requiring extreme durability under severe conditions, alternative alloys may be necessary.
Hastelloy C-22: Pros and Cons
Hastelloy C-22 is one of the most corrosion-resistant alloys available for industrial filtration, making it indispensable in environments where stainless steels fail. Its composition, consisting of approximately 56% nickel, 20-22% chromium, 12.5-14.5% molybdenum, and 2.5-3.5% tungsten, creates a robust passive film that resists attack from both oxidizing and reducing agents. This unique chemistry allows C-22 to withstand aggressive conditions such as mixed acid streams, halide rich environments, and wet chlorine, where 316 stainless steel would corrode rapidly. It offers outstanding resistance to pitting, crevice corrosion, and stress corrosion cracking, even under alternating oxidizing and reducing conditions.
From a thermal standpoint, Hastelloy C-22 maintains structural integrity and corrosion resistance at temperatures up to approximately 700°C (1,290°F) in reducing environments and even higher in oxidizing atmospheres, making it ideal for hot gas filtration systems exposed to sustained extreme heat. Its mechanical properties are impressive, with an even higher tensile and yield strength than 316 stainless steel, combined with excellent ductility.
These characteristics ensure long service life in critical applications such as waste-to-energy incineration, chemical process off-gas filtration, and pre-SCR polishing stages where acid dew points are routinely crossed.
However, these benefits come at a cost. Hastelloy C-22 is significantly more expensive than 316 stainless steel, often several times higher per pound, due to its high nickel and molybdenum content and specialized manufacturing requirements. Availability can also be limited, with longer lead times compared to stainless steel.
Fabrication requires careful process control to maintain corrosion resistance, and while weldability is good, improper handling can lead to sensitization.
In short, Hastelloy C-22 is the alloy of choice for the harshest chemical and thermal environments, offering unmatched corrosion resistance and operational reliability. Yet, its high cost and fabrication complexity mean it should be reserved for applications where failure is not an option, such as chemical processing, pollution control, and energy-to-waste systems.
Balancing Performance and Budget
When it comes to hot gas filtration, the choice between 316 stainless steel and Hastelloy C-22 is not only a technical decision but a strategic one. As we’ve explored, 316 stainless steel offers a cost-effective solution for moderate environments, delivering reliable corrosion resistance and mechanical strength where acid dew point corrosion is controlled. Hastelloy C-22, on the other hand, stands out in the harshest conditions, providing unmatched resistance to aggressive chemicals and high temperatures, ensuring long-term reliability when failure is not an option.
Next steps involve evaluating your process conditions carefully. Consider factors such as operating temperature, gas chemistry, and maintenance intervals. If your system faces unpredictable fuel mixes, frequent acid condensation, or highly corrosive streams, investing in Hastelloy C-22 can prevent expensive downtime and help to extend service life. For applications where conditions are stable and moderately corrosive, 316 stainless steel remains the practical choice for balancing performance and budget.
At W.S. Tyler, our commitment is to help you achieve cleaner, safer, and more efficient operations through precision-engineered woven wire mesh solutions. Backed by over 150 years of experience, we design filtration media that not only meets stringent environmental standards but also optimizes energy efficiency and system reliability.
Want to discover more about the customization capabilities of woven wire mesh and how it can work for your system? Learn more in our article below: