The grades of stainless steel for air tanks during custom air storage tanks

Besides carbon steel, stainless steel is another major material for air storage tanks. Due to its excellent corrosion resistance, strength, and hygienic properties, stainless steel air receiver tanks are becoming increasingly popular in various modern industries, especially those prioritizing production reliability and product quality, such as the food, pharmaceutical, and electronics industries.

For stainless steel air tanks, the most common grades are as following, during custom air tanks, customers should specify the exact grade to the air tank factory.

304 Stainless Steel

A general-purpose stainless steel with excellent corrosion resistance, heat resistance, low-temperature strength, and mechanical properties. It resists most common atmospheric corrosion, water, and many chemicals.

Applications: 304SS is the most commonly used stainless steel material for air tanks. It is suitable for storing compressed air, nitrogen, and other general industrial gases, as well as for applications where corrosion resistance is not critical. It offers a high cost-effectiveness.

316 Stainless Steel

Molybdenum (Mo) added to 304SS becomes 316SS. Significantly enhances corrosion resistance, especially in environments containing chlorides (such as salt water, seawater, and de-icing salt).

Applications: Typically used in more corrosive environments. For example:

▪ Coastal areas (where the air is salty).

▪ Compressed air may contain small amounts of oil or corrosive impurities.

▪ Storage of specialty gases (such as certain chemical process gases).

▪ Industries requiring extremely high purity (such as high-end food, pharmaceuticals, and semiconductors).

During customizing air tanks from air tank manufacturer, customers may have no idea on which grade to choose from, the following key factors for reference:

1. Medium (Stored Gas):

◦ Compressed air? Nitrogen? Oxygen? Or other special gases?

◦ Air purity and humidity? Wet air is more easy to corrosive.

◦ If contain oil vapor,or other chemical contaminants?

2. Environment:

◦ Will the air tank be installed indoors or outdoors?

◦ If outdoors, is the environment industrial (may has acid rain), urban, or coastal (high in salinity)? For coastal environments, 316 stainless steel is preferred.

3.Cost and budget:

316SS air tanks are much more expensive than 304SS air tanks. Customers should balance between performance and cost.

For most general industrial applications: 304 stainless steel air tanks are enough and cost-effetive.

316 stainless steel is strongly recommended for the following situations:

◦ coastal areas or high-humidity, high-salt environments.

◦ Applications requiring extremely high compressed air quality (e.g., food, pharmaceutical, electronics, spray painting).

◦ Post-processing equipment (dryers, filters) in the compressed air system may occasionally fail, resulting in corrosive, wet air to enter the tank.

◦ High budge, desire for a longer equipment life with minimal maintenance risk.

No matter which grade of stainless steel, air storage tanks, as pressure vessels, must be designed and manufactured in strict compliance with relevant standards. When purchasing, be sure to select a reputable air tank manufacturer with the appropriate qualifications and certifications (such as the "ASME U Stamp," "CE PED Certification," or China's "Pressure Vessel Production License").