Pressure Vessel Steel
Pressure vessels are storage tanks that are designed to contain or resist pressures up to a certain limit. Pressure vessel steel is specifically designed to meet the standards and requirements set by the world’s governing bodies for the safe and efficient containment of hazardous chemicals, gases and liquids. Depending on their size, pressure vessels can be categorized as either large-Diameter Pressure Vessels (LDPV) or small-Diameter Pressure Vessels (SDPV).
In terms of the different grades of materials that can be used to construct pressure vessels, stainless steel is one of the most widely preferred materials because of its significant durability, corrosion resistance and high-temperature capabilities. The selection of the most suitable type of stainless steel for a particular application is often dependent on the operating temperature, pressure and the chemical composition of the contents of the pressure vessel.
In general, the most commonly used stainless steel for pressure vessels are the austenitic stainless steel grades, such as the 304/304L and 316/316L, which are classified as austenitic alloys composed of iron and chromium. These stainless steel grades possess great formability and weldability, as well as good corrosion resistance across a relatively broad temperature range.
The most widely used low-alloy pressure vessel steel grades for the manufacture of pressure vessels are ASTM A516 and ASTM A537. These grades of steel are generally employed for the construction of LDPVs and are widely considered to be the best all-round choice for most applications.
Both ASTM A516 and ASTM A537 contain additional elements, such as aluminum, chromium, molybdenum, nickel and silicon, which contribute to their higher strength and enhanced corrosion resistance. It is also essential to note that the carbon content of these grades is the main difference between them, with the ASTM A516 grade containing a much higher level of carbon than the ASTM A537. Therefore, the A516 grade can provide higher strength levels at higher temperatures, whereas the A537 grade is more suitable for relatively lower temperature applications.
In addition to the carbon content, the other important consideration when selecting the most suitable steel grade for your pressure vessel is the weldability. The weldability of pressure vessel steel is related to the microstructure of the alloy, so when it comes to steels with a low carbon content (such as the ASTM A537), an additional carbon-manganese composition can be added to the structure’s microstructure to improve the weldability.
Overall, pressure vessel steel is a highly specialized form of metal that can provide unique advantages in terms of durability, strength and corrosion resistance when compared to other steel types. As long as the correct grade is selected when designing and constructing a pressure vessel, the end-product will perform to the highest standards that are set by the relevant governing bodies.