The Most Corrosive Materials to Industrial Valves


acid tank for industrial valve service
Valves that transfer highly corrosive materials require experienced industrial valve service to stay safe and efficient.

Industrial valves are used in service for countless processes across manufacturing, chemical plants, power generation, and more. These precisely engineered devices regulate the flow of everything from liquids and gases to slurries, ensuring safe and controlled operations. However, over time, exposure to harsh environments can lead to corrosion, which slowly degrades valve components. This can result in leaks, costly downtime, and even safety hazards.

Corrosive chemicals relentlessly attack metals and other valve materials. Understanding the most common corrosive culprits is the first step in selecting effective strategies to fight back. Today, we will discuss some of these destructive substances and how to help counteract them to preserve the integrity and lifespan of your industrial valves.

Minimize downtime and extend valve life in even the most challenging environments—Southern Valve Service offers complete repair, modification, and field services. Contact us for an industrial valve service quote now.

Common Corrosive Materials Used in Industrial Processes

Harsh substances threaten the integrity of industrial valves. These are some of the most commonly-used corrosive materials that can compromise the body and components of different valves.

  • Hydrochloric Acid (HCl): A highly acidic solution, HCl is essential in industries like metal pickling (removing oxides), ore processing, and chemical production. It aggressively attacks common metals like carbon steel and many grades of stainless steel.
  • Hydrofluoric Acid (HF): Found in semiconductor manufacturing and other industries, HF attacks even most stainless steels. Only specialized plastics or tantalum can generally withstand it.
  • Sulfuric Acid (H2SO4): This powerhouse acid is foundational for fertilizer production, petroleum refining, metal processing, and countless other applications. Its corrosiveness is complex – lower concentrations can be less damaging than mid-range, and higher concentrations sometimes form a protective layer. Nonetheless, most steels are vulnerable to its attack.
  • Nitric Acid (HNO3): A strong oxidizer, nitric acid is used in fertilizer and explosives production and for metal etching. It rapidly attacks carbon steel and lower-grade stainless steels. Alloys with higher chromium and molybdenum content offer better resistance.
  • Acetic Acid (CH3COOH):  This organic acid is prevalent in food, pharmaceutical, and chemical industries. While milder than mineral acids, it can still corrode carbon steels and cause specific issues like pitting in some stainless steel grades.
  • Chlorine (Cl2):  Used in water treatment, sanitation, and various chemical processes, chlorine (especially in wet environments) can be highly corrosive to many metals. Specialty alloys or titanium may be required.
  • Phosgene (COCl2): A highly toxic industrial chemical, phosgene can form as a byproduct when chlorinated solvents are exposed to high temperatures. It necessitates extremely corrosion-resistant materials and extreme safety precautions.
  • Alkali (e.g., Sodium Hydroxide/NaOH): Strong bases like NaOH (caustic soda) are used in papermaking, soap production, and water treatment. They don’t directly damage stainless steels but can swiftly degrade carbon steels and certain types of plastics.
  • Ammonia (NH3):  In gaseous or liquid form, ammonia is crucial for fertilizer production. Prolonged exposure can cause stress corrosion cracking in copper-based alloys, and some steels may be vulnerable under specific conditions.
  • Saltwater: The combination of salt and dissolved oxygen in seawater creates a highly corrosive environment. It can degrade most steels and even attack specific stainless steel grades over time.

Choosing the Correct Body Material – Industrial Valve Service

Selecting the right material for a valve body is the foundation of corrosion defense. The key is to match the material’s properties to the specific corrosive chemicals it will encounter. Here is a breakdown of some common choices:

  • Stainless Steel (different grades): Stainless steels offer enhanced corrosion resistance due to their chromium content.  Grade 316 stainless steel is widely used, while higher-alloy variants like 904L or duplex stainless steels are essential for severe environments. Crucial to note: Not all stainless steels are equal when it comes to specific acids.
  • Duplex Stainless Steels: These steels boast a mixed microstructure providing excellent strength and greater resistance to stress corrosion cracking. They often outperform standard stainless steel grades in chloride-rich environments.
  • Nickel-Based Alloys (Monel, Inconel): These high-performance alloys excel in extreme conditions and handle a wide range of corrosive substances like acids, alkalis, and saltwater. While expensive, they offer superior durability and long-term value.
  • Fluoropolymers (PTFE, PVDF): These plastics offer exceptional chemical resistance across a broad range of temperatures and are resistant to most acids and bases. They often form sleeve linings of valves handling highly corrosive fluids.

Consideration of the process conditions, including the exact chemicals, their concentration, and temperature, is crucial for making an informed, cost-effective selection of the right industrial valve.

Alternative Measures – Cathodic Protection

Cathodic protection can be a powerful way to shield metal valves from corrosion. It works by making the valve the cathode of an electrochemical cell, preventing the metal from losing electrons and dissolving (i.e., corroding). There are two main methods:

  • Sacrificial Anodes: A more reactive metal (like zinc or magnesium) is connected to the valve. This “sacrificial” metal preferentially corrodes, sending electrons to the protected valve.
  • Impressed Current Systems:  An external power source is used to drive current onto the protected valve.  An anode, often made from inert materials like titanium, completes the circuit. This method is powerful for large structures and harsh environments.

Both methods effectively create a protective barrier on the valve’s surface. When the metal is forced to accept electrons, the chemical reactions that lead to corrosion are essentially halted.

Experienced Industrial Valve Service and Repair

Corrosion poses a relentless threat to the lifespan and reliability of industrial valves. The destructive effects of harsh chemicals can lead to costly leaks, downtime, and safety risks. However, a proactive approach can ensure long-term protection. By understanding the characteristics of corrosive substances and selecting appropriate valve materials, you can help safeguard these vital components of your operations.

For customized valve solutions to combat corrosion, turn to Southern Valve Service. We have decades of experience in industrial valve repair and service. Contact us today for a quote to optimize the performance and longevity of your valves.