Choosing suitable stainless steel and alloys for sanitary processing equipment is essential, as corrosion-related system failure can have significant consequences. With so many corrosion-resistant options available, the science of corrosion can be difficult to comprehend. However, corrosion is extremely situation-specific and can be impacted by unforeseen factors such as pollutants. That’s why professionals need to evaluate the unique needs of their system and make an informed decision when selecting suitable stainless steel and alloys.
By proactively addressing corrosion, you can be sure that your equipment is protected and your system is running efficiently. In addition, with suitable stainless steel and alloys for your unique setup, you can rest assured that your system is running as effectively as possible.
When it comes to high-performance alloys, Hastelloy C-22 and Hastelloy C-276 are two of the most popular options on the market. However, both alloys offer excellent corrosion resistance and high strength, so deciding which is best for your needs is challenging.
In this article, we’ll take a closer look at both Hastelloy C-22 and C-276 and explore their unique properties and potential applications. We’ll also provide tips for making the right choice for your processing environment.
Hastelloy C-22 vs Hastelloy C-276
HASTELLOY FAMILY
| Alloy | Chromium | Nickel | Molybdenum |
| Hastelloy C-22 | 22% | 56% | 13% |
| Hastelloy C-276 | 16% | 57% | 16% |
CRITICAL PITTING AND CRITICAL CREVICE CORROSION TEMPERATURES
| Alloy | CPT* °C | CPT* °F | CCCT* °C | CCCT* °F |
| Hastelloy C-22 | >150 | >302 | 102 | 212 |
| Hastelloy C-276 | 150 | 302 | 80 | 176 |
Hastelloy is a family of corrosion-resistant alloys renowned for their strength and durability. C-22 and C-276 are two of the most popular alloys within the family, but they possess different properties.
Hastelloy C-22 and Hastelloy C-276 are two highly corrosion-resistant alloys commonly used in demanding sanitary processing applications, such as foods and beverages, household goods, pharmaceuticals, and personal care products. These alloys are ideal for these applications because they can withstand harsh chemicals, high temperatures, and constant cleaning while maintaining product purity and avoiding contamination.
As part of the “Hastelloy” brand, these alloys are among the 20 high-performance alloys with nickel as their main component. From a professional perspective, Hastelloy C-22 and C-276 are ideal solutions for sanitary processing.
Chromium’s Critical Corrosion Protection
Chromium provides critical corrosion protection for essential processing equipment. C-22 and C-276 are highly resistant to corrosion, much more so than any stainless steel. The corrosion resistance of these materials is enhanced even further by the addition of chromium. While other elements, such as molybdenum, can boost chromium protection, chromium remains essential for maximum corrosion resistance.
When a system is first put into service, chromium reacts with oxygen and creates a thin, protective coating of chromium oxide (Cr2O3) on the interior surface of the equipment. This coating is essential to ensure maximum corrosion resistance. C-22 is commercially available in sanitary and high-purity tubing, whereas C-276 is not. For professionals in the processing industry, chromium is a critical component for corrosion protection.
By understanding the importance of chromium and its benefits, professionals can ensure the longevity of their equipment and the safety of their operations.
Corrosion and the Processing Environment
Choosing suitable materials when building a sanitary processing system is essential to protect it from corrosion and other potential damages. However, the material selection process should consider not only the type of environment in which the system will be operated but also the internal environment of the system itself. For example, technologies exist to detect corrosion inside a processing system, but these solutions are only effective after the decline has already started and do not prevent it from developing. Ultimately, corrosion begins inside the system, so the materials chosen must be robust enough to withstand any unforeseen internal conditions.
In essence, corrosion is a chemical reaction caused by metals interacting with aggressive species in the environment, resulting in the dissolution of metal ions and the accumulation of corrosion products. This reaction is typically more active at higher temperatures. It is important to note that corrosion can be detrimental to the integrity of metals if not adequately monitored and managed. Therefore, professional engineers must be aware of the potential for corrosion in metal structures and take appropriate measures to mitigate its effects.
At temperatures below the boiling point, wet corrosion is a significant concern for processing equipment due to corrosive chemicals suspended or dissolved in water. As a result, we focus on aqueous corrosion, which is the corrosion process caused by these wet materials and liquid cleaning solutions. To ensure optimal performance and longevity of our processing equipment, we are committed to mitigating risks associated with aqueous corrosion.
What’s Best For Your Sanitary Processing Environment?
Compared to other stainless steels, C-276 and C-22 both offer exceptional corrosion resistance; however, C-22 is readily available for purchase in sanitary or high-purity tubing, while C276 is not. Professional buyers should take note of this distinction when making their selections, as C-22 is the more accessible option for sanitary or high-purity applications.
C-22 and C-276 offer nearly equal protection in decreasing conditions. However, due to its increased chromium concentration, C-22 provides superior general corrosion resistance and enhanced localized corrosion resistance in chloride-containing environments, a common occurrence in sanitary processing. Professional engineers should take note of this difference when selecting a suitable material for their application.
If you’re still unsure which material will be best for your project, contact Instruthinkat sales@instruthink.com or visit our website at www.instruthink.com. We can help you select the best materials for your particular application.
