What materials are typically chosen for high-pressure storage tanks?

The material selection for high-pressure storage tanks is determined based on a comprehensive consideration of pressure rating, media characteristics, and environmental conditions. Carbon steel series such as Q345R are a common choice, offering good strength, plasticity, and economy, suitable for medium and low-pressure storage tanks containing non-corrosive media. Low-alloy high-strength steels such as 16MnDR and 15CrMoR are used for higher pressure or cryogenic conditions, with the addition of elements such as Mn, Cr, and Mo to enhance strength and cryogenic toughness. Stainless steel materials such as 304 and 316L are suitable for corrosive media; their austenitic structure provides excellent acid and alkali resistance, but attention must be paid to chloride stress corrosion. Duplex stainless steel 2205 combines high strength and corrosion resistance, suitable for harsh corrosive-high-pressure combined environments.

Special media storage requires specialized materials: liquid hydrogen storage tanks use austenitic stainless steel 304L or aluminum alloys to maintain cryogenic toughness; hydrogen sulfide environments require materials resistant to hydrogen embrittlement that meet NACE MR0175 standards; for strongly oxidizing media, Hastelloy C-276 or titanium can be selected. Composite material designs can balance cost and performance, such as carbon steel base lined with stainless steel or nickel-based alloys. Material certification must include chemical composition analysis, mechanical property testing, and impact testing. Plates thicker than 30mm require Z-axis performance testing to prevent lamellar tearing. Welding consumables must be matched to the base material; low-hydrogen electrodes are used for carbon steel, and ultra-low carbon welding wire is used for stainless steel to prevent intergranular corrosion. The heat treatment state (normalizing, quenching and tempering) of the material must be determined based on the design stress level. Post-weld heat treatment (PWHT) is mandatory for thick-walled vessels.