Acquisition of right material for the pressure vessel
A bad selection of material can impact the quality of pressure vessel leads to failure. So selecting the right material for specific tank application is as important as the design. If we opt for the wrong material under economic valuation this may lead to a number of issues, like poor performance and lower efficiency, to catastrophic failure and reduced safety.
When ordering a tank it is obligatory that a material test report be provided according to The National Board of Boilers and Pressure Vessels Inspectors. We can’t just only rely on this to prevent certification errors and incorrect acquiring of pressure vessel material.
Let’s go through the materials ideal for a pressure vessel
1. Carbon Steel – When we are talking about pressure vessel material Carbon steel is unavoidable. It has a wide range of applications in making tanks and industrial application because of its resistance to corrosion, shock and vibration and also high tensile strength. It is a much economic option which reduces the fabrication cost as it can retain strength at minimum thickness which reduces the amount of material. It has a much lower impact over environment than all other materials because it is recyclable. Approximately 52 % of its production comes from reclaimed materials.
2. Stainless Steel – Stainless steel also have the quality of high tensile strength as carbon steel. It provides high strength with minimal material. Surprisingly it is also highly recyclable. We can go on counting different kinds of stainless steel. Two most common used types are 304 and 304L. Type 304 shows unmatchable chemical and corrosion resistance whereas in 304L as the carbon content is low it shows the property of weld ability. We can readily conclude that stainless steel can withstand natural environment (humidity, sunlight) or high temperatures.
3. Aluminium – It is usually used as an alternative material instead of stainless steel. If we are taking aluminium it three times less dense than stainless steel and we can manage its tensile strength even by making alloy forms. An added advantage of aluminium is that it is cheaper than stainless steel and the production is much easier.Sometimes, labour costs may be higher, as some aluminium tank fabrication requires the use of special welding techniques. It has a lower density so is not suitable in extreme weather conditions.
4. Nickel Alloy – Nickel also have different grades. It shows best properties with its alloys. For instance, chromium can be added to nickel alloy to provide more heat resistance. Copper can also be added for use in salt-water environments. Notably we can see that nickel vessels are used in Liquefied Natural Gas(LNG) storage. With other amalgams manufacturing process for this nickel alloy can be complex.While tank fabrication is performed only purest materials can be inculcated for material integrity. These complexities may increase the cost of production but it will pay off by providing excellent corrosion resistance and protection against thermal expansion.
5. Hastelloy –Hastelloy has outstanding resistance to highly oxidizing and reducing agents, making it a great choice for moderate to severe corrosive environments. It is commonly used for pipes and valves in the chemical processing and petrochemical industries. The proper maintenance rewards with decades of the lasting of the material. They can also save the manufacturer or client from a leaking pocket for maintenance.
The corrosive resistance of hastelloy provides a shield against corrosive liquids that may result in localized or uniform attack. In the case of cracking it shows a impeccable resistance. Moreover, it is extremely workable (easy to weld or fabricate) and is available in a wide range of types (B2, S, C, C276, etc.)
6. Titanium – Titanium shows same result as copper nickel alloys in salt-water environments. Its added advantage of resistance to corrosion reduces cleaning and maintenance requirements. It allows increased strength and durability even with lower thickness and proves to provide efficient heat transfer than other types of materials. It is mostly used in power station condensers and similar applications.
We can conclude that each of the metals we discussed above shows their own independent properties. They have their own pros and cons. When we are considering different types of pressure vessels our view towards material selection should be staggered and should be individualistic in accordance with the pressure vessel. Even we made the design splendid it is a matter of keen observation while selecting the manufacturer and safety should be the pivotal subject.
Universal Engineering’s professional design engineering services wing offers design and detail engineering services for pressure vessel, heat exchanger, piping engineering, 3D detailed design, structural design, pipe supporting structure analysis, Skid packages, FEA, and spotless service on design management.
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