Pressure vessels are sealed containers used for storing gases or liquids and are typically subjected to certain pressures. They can be categorized based on the pressure they are designed to withstand, material composition, and application fields. According to the pressure rating, pressure vessels are divided into low-pressure, medium-pressure, high-pressure, and ultra-high-pressure vessels. The manufacturing of pressure vessels involves design, material selection, fabrication, and inspection to ensure quality and safety. The design of pressure vessels must consider factors such as shape, size, material, thickness, and pressure, as well as the necessity for inspection and maintenance. Common pressure vessels include gas storage tanks, compressed air tanks, nitrogen cylinders, oxygen cylinders, and y-grade nitrogen storage tanks, and are widely used in industries and scientific research fields.