In many industrial environments, pressure vessels face the challenges of various corrosive media, so corrosion resistance is a key consideration when selecting materials.

1. Analysis of media characteristics

First, it is necessary to clarify the composition of the medium that the pressure vessel is exposed to. If it is an acidic medium, such as strong corrosive acids such as sulfuric acid and hydrochloric acid, it is necessary to select materials with excellent acid resistance. For example, in a pressure vessel that handles concentrated sulfuric acid, high silicon cast iron exhibits good corrosion resistance; for media containing chloride ions, since chloride ions easily cause pitting, duplex stainless steel in stainless steel has a unique advantage in resisting chloride ion corrosion. In alkaline media, nickel and nickel alloys tend to have good corrosion resistance.

2. Effect of temperature and pressure

Temperature and pressure affect the rate and type of corrosion. Under high temperature conditions, the corrosion mechanism of materials may change. For example, in a high temperature and high pressure water vapor environment, the corrosion rate of carbon steel will increase significantly, and chromium-molybdenum alloy steel with better oxidation resistance may need to be selected. At the same time, the increase in pressure may make it easier for corrosive media to penetrate into the material, aggravating the degree of corrosion, which requires the material to maintain its corrosion resistance under the corresponding pressure.

3. Cost and machinability

On the premise of meeting the corrosion resistance requirements, the cost and machinability of the material cannot be ignored. Although some rare metals have excellent corrosion resistance, they are expensive, which limits their large-scale application. For example, tantalum has excellent corrosion resistance, but it is expensive. Composite materials such as fiberglass are relatively low in cost and have good corrosion resistance, and are good choices in some medium and low pressure, non-extreme corrosive environments. In addition, the machinability of the material affects the manufacturing efficiency and quality of the pressure vessel. Materials that are easy to cut, weld and form are more conducive to the manufacturing process.