10 Things to Consider When Buying 316 and 316L Valve Balls

Choosing the right stainless steel grade is essential for ensuring the performance, durability, and cost-effectiveness of valves in various industries. When deciding how to choose between 304, 304L, 316, and 316L stainless steel, it’s important to understand their key differences in composition, corrosion resistance, weldability, and cost. 304 is a versatile and economical option for general applications, while 304L offers better weldability due to its lower carbon content. For more demanding environments, 316 provides enhanced resistance to chlorides and acids, and 316L combines these benefits with improved weldability, making it ideal for high-stress, corrosive conditions. This guide breaks down the properties, applications, and key factors to consider when selecting the right grade for your valves, helping you make an informed decision that balances upfront costs with long-term performance.

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304 Stainless Steel: The Industry Standard

Properties

Type 304 stainless steel, also known as 18/8 stainless steel, is an austenitic alloy primarily composed of 18% chromium and 8% nickel. This composition provides excellent corrosion resistance, making it suitable for various environments. The alloy exhibits good mechanical strength, with a tensile yield strength around 215 MPa in the annealed condition. Its austenitic structure also ensures non-magnetic properties and excellent formability and weldability. 

Common Applications​

Due to its versatility and favorable properties, 304 stainless steel is widely used across various industries. Common applications include:​

• Household Items: Kitchen sinks, cookware, and cutlery.​

• Industrial Equipment: Food processing units, chemical containers, and brewing equipment.​

• Architectural Components: Building facades and decorative elements.​

Its widespread use is attributed to its durability, aesthetic appeal, and resistance to oxidation. ​

Limitations​

Despite its numerous advantages, 304 stainless steel has certain limitations:​

• Susceptibility to Chlorides: It is prone to pitting and crevice corrosion in chloride-rich environments, such as coastal areas or exposure to de-icing salts.​

• High-Temperature Sensitization: Prolonged exposure to temperatures between 500°C and 800°C can lead to sensitization, reducing its corrosion resistance.

304L Stainless Steel: Optimized for Welding

Key Difference​

304L stainless steel is a low-carbon variant of the standard 304 grade, containing a maximum of 0.030% carbon compared to 0.08% in 304. This reduction in carbon content minimizes the risk of carbide precipitation during welding, which can otherwise lead to intergranular corrosion. As a result, 304L offers improved weldability while maintaining similar corrosion resistance and mechanical properties to 304. ​

Use Cases

Due to its enhanced weldability and cost-effectiveness, 304L stainless steel is commonly used in:​

• Welded Valves in Mildly Corrosive Settings: Ideal for applications where welding is required, such as in valves exposed to environments with low to moderate corrosion risk.​

• Budget-Sensitive Projects: Suitable for projects that require corrosion-resistant materials without incurring the higher costs associated with more specialized stainless steel grades.

316 Stainless Steel: Superior Defense Against Corrosion

Enhanced Properties

316 stainless steel is an austenitic alloy distinguished by the inclusion of molybdenum (Mo), typically comprising 2–3% of its composition. This addition significantly enhances its resistance to pitting and crevice corrosion, especially in chloride-rich environments such as seawater. The presence of molybdenum also improves the alloy’s overall durability and ability to withstand acidic conditions, making it more resilient than standard 304 stainless steel. 

Ideal Applications

Due to its superior corrosion resistance and mechanical properties, 316 stainless steel is ideally suited for:​

• Chemical Processing: Its ability to withstand exposure to aggressive chemicals and acidic environments makes it a preferred material for equipment like tanks, pipes, and heat exchangers in the chemical industry. ​

• Coastal and Marine Environments: Known as “marine grade” stainless steel, 316 is extensively used in marine applications due to its resistance to saltwater corrosion. Common uses include boat fittings, marine hardware, and coastal architectural components. ​

• Harsh Industrial Use: In industries where exposure to corrosive substances is frequent, such as oil and gas or pharmaceuticals, 316 stainless steel ensures longevity and reliability of components like valves, pumps, and reactors.

316L Stainless Steel: The Premium Choice for Extreme Conditions

Advantages

316L stainless steel is a low-carbon variant of the standard 316 grade, with carbon content reduced to a maximum of 0.03%. This reduction minimizes the risk of carbide precipitation during welding, thereby enhancing its resistance to intergranular corrosion. The alloy’s composition includes 16–18% chromium, 10–14% nickel, and 2–3% molybdenum. The addition of molybdenum significantly improves its corrosion resistance, particularly against chlorides and other industrial solvents. These properties make 316L stainless steel exceptionally suitable for applications requiring both high corrosion resistance and extensive welding.​

Where It Shines

316L stainless steel excels in environments characterized by high temperatures, high pressures, and high corrosiveness. Its enhanced mechanical properties and superior resistance to various forms of corrosion make it the material of choice for critical valve applications in industries such as chemical processing, marine, and pharmaceuticals.

Key Factors to Choose Between 304, 304L, 316, and 316L Stainless Steel

Choosing the appropriate stainless steel grade for valve applications is crucial to ensure durability, performance, and cost-effectiveness. The following key factors should guide your selection process:​

1. Environmental Exposure

• Chlorides and Acids: Environments rich in chlorides (e.g., seawater) or acids can accelerate corrosion. Grades like 316 and 316L, containing molybdenum, offer enhanced resistance to such corrosive agents.​

• Humidity Levels: High humidity can promote corrosion, especially in the presence of pollutants. Austenitic stainless steels, such as 304, provide good resistance in humid conditions.​

2. Fabrication Needs

• Welding Requirements: If welding is integral to the valve fabrication, selecting low-carbon variants like 304L or 316L is advisable. The reduced carbon content minimizes carbide precipitation, maintaining corrosion resistance post-welding.​

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• Post-Weld Corrosion Risks: In applications where post-weld heat treatment isn’t feasible, using stabilized grades or low-carbon versions helps prevent intergranular corrosion.​

3. Operational Demands

• Temperature and Pressure: Valves operating under high temperatures and pressures require materials that maintain strength and integrity. Grades like 316 and 316L are suitable for such demanding conditions.​

• Mechanical Stress: Applications involving significant mechanical stress necessitate stainless steels with higher tensile strength and toughness. Duplex stainless steels offer a balanced combination of strength and corrosion resistance.​

4. Budget Constraints

• Cost vs. Performance: While higher alloyed stainless steels provide superior properties, they come at increased costs. Assessing the specific environmental and operational requirements allows for selecting a grade that balances performance with budget considerations.

Head-to-Head Comparison: 304, 304L, 316, and 316L Stainless Steel

Selecting the appropriate stainless steel grade is crucial for ensuring optimal performance, durability, and cost-effectiveness in various applications. Below is a comparative overview of the four commonly used grades: 304, 304L, 316, and 316L.​

Key Takeaways:

• 304: Suitable for general-purpose applications with good corrosion resistance and formability.​

• 304L: Ideal for welded structures where post-weld heat treatment is impractical; reduces risk of intergranular corrosion.​

• 316: Preferred in environments exposed to chlorides or harsh chemicals; offers superior corrosion resistance due to molybdenum content.​

• 316L: Optimal for applications involving extensive welding and exposure to corrosive environments; combines low carbon content with molybdenum for enhanced performance.

FAQs About Stainless Steel Grades for Valves

1.Can 304 stainless steel be used in marine environments?

While 304 stainless steel offers good general corrosion resistance, it is susceptible to pitting and crevice corrosion in chloride-rich environments, such as seawater. Therefore, it is not the optimal choice for marine applications. For enhanced resistance to such conditions, 316 stainless steel, which contains molybdenum, is recommended.​

2.Why does low carbon improve welding performance?

Low-carbon variants like 304L and 316L stainless steels have reduced carbon content, which minimizes the risk of carbide precipitation during welding. This reduction prevents the formation of chromium carbides at grain boundaries, maintaining corrosion resistance and preventing intergranular corrosion.​

3.Is 316L worth the extra cost for non-corrosive applications?

316L stainless steel offers superior corrosion resistance, particularly in chloride-rich and acidic environments, due to its molybdenum content and low carbon composition. However, in non-corrosive applications where such enhanced properties are unnecessary, 304 or 304L stainless steels can provide adequate performance at a lower cost. Therefore, the additional expense of 316L may not be justified in these scenarios.

Conclusion

2.What standard or regulation does a sanitary valve requires?

3-A sanitary standard. The most common standard use in American for valve and fittings is 3-A sanitary standard.  Which is specify the criteria for the design and fabrication of equipment that comes into contact with food. The guiding purpose of 3-A Sanitary Standards is to protect public health by using sanitary equipment. Want to know more about 3-A standard, please check this article A Primer for 3-A Sanitary Standards and 3-A Accepted Practices? Donjoy Sanitary valve and fittings are all hygienic design and meet 3-A standard.

FDA standard. The full name is the U.S. Food and Drug Administration(FDA Wikipedia ), which is another standard applied to valve gasket. Donjoy valve seal (e.g EPDM, PTFE, FPM, Silicone, NBR, HNBR) all comply with FDA standard.

ASME BPE standard is related to how to design and manufacture bioprocessing equipment like valve and pipe fittings intended for use in biopharmaceutical and personal-care products industries. Donjoy sanitary valve and pipe fittings as well as meet the standard. For more details please refer to ASME Wikipedia

3.What’s difference between a sanitary valve and an industrial valve?

Material. The sanitary valve body material must use health standards of stainless steel ASI 304 or 316L. But industrial valve body commonly uses carbon steel, alloy steel, cast iron or bronze, which are easily corroded or rust.

Metal surface. The hygienic valve and tube fittings require a high standard of the roughness to the metal surface, all parts that contact with the medium must be finely polished. Surface roughness is calculated measuring the average of surface heights and depths across the surface. This measurement is most commonly shown as “Ra”. SF1 RA20=0.51μm.

The ASME BPE surface finish table as below:

Seal. The seal inside hygienic valve is critical, must meet health standard. Donjoy sanitary valve seal comply with FDA standard.

4. The different application for the sanitary valve and industrial valve.

The sanitary valve application is food processing, water, beverage, brewing, dairy, daily chemical, pharmaceutical industries…

The industrial valve application is oil, gas, slurry, agriculture…

5. What types of sanitary valve have?

• Donjoy sanitary butterfly valve
• Donjoy sanitary ball valve
• Donjoy sanitary diaphragm valve
• Donjoy sanitary shutoff valve
• Donjoy sanitary check valve
• Donjoy sanitary mixproof valve
• Donjoy sanitary tank bottom valve
• Donjoy sanitary pressure relief valve
• Donjoy sanitary sampling valve

6.Valve Connection Type

There are some functional characteristics to end types. Connection end for sanitary valve include:

• Butt-welded Typically used in high-pressure or high-temperature operations
• Tri-clamped Easy for installation and maintenance
• Threaded For low-pressure pipe connection
• Flanged The most common industrial valve ends for high-pressure pipe connection

7.Sanitary Valve Connection Standard and Size: Matching the Pipeline

DIN and 3A, SMS dimension are most commonly used for sanitary pipe connection. Sanitary valve size often means valve port refer to the outside diameter(OD) of pipe.

DIN DIN standards refer to a series of technical standards originating in Germany. These standards are widely used throughout Europe to ensure norms for quality control, safety, environmental protection and rationalisation. Our sanitary butterfly valve DIN size is from DN10 to DN 300.

3A,SMS dimension in inches. It’s the most widely connection standard used in the world.

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