A Brief Overview of the Pressure Vessel Fabrication Process

What comes to mind when you think of a pressure vessel? Perhaps it is a large or small cylindrical tank that holds liquids or gases under high pressure. Whatever the size or application, all pressure vessels have one thing in common: they must be built to withstand significant internal pressure without leaking or failing. With years of experience, Heartland Repair and Coatings has a wealth of knowledge in the pressure vessel fabrication process, and you can rest assured that your pressure vessel will be built to the highest standards.

large industrial water treatment boiler room with piping and pressure vessel

What Is a Pressure Vessel?

Simply put, a pressure vessel is a container designed to hold liquids, gases, or vapor at a pressure different from ambient, which is ideally above 15 psig. Depending on the vessel’s intended application, they are usually made from strong, durable materials like stainless steel.

It is important to note that the pressure vessels come in different shapes and sizes depending on the application’s needs. Most are cylindrical but can be oriented horizontally or vertically.

It is important to note that the pressure vessels come in different sizes depending on the application’s needs. A pressure vessel can be horizontal or vertical; however, most are cylindrical.

American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code regulates the construction of pressure vessels. It establishes rules for the design, fabrication, inspection, and testing pressure vessels. 

Heartland Repair & Coatings has obtained ASME U1, U2, and U3 stamps for pressure vessel fabrication, and our team of experts fabricates high-quality products that meet the ASME standards.

autoclaves in a factory setting

Types of Pressure Vessels

There are different types of pressure vessels, including;

  • Reactors – made using high-grade steel such as super duplex or carbon steel and are designed to contain chemical reactions.
  • Columns and towers – primarily employed in the oil and gas industries and typically constructed using carbon steel.
  • Separators – used to separate different phases of a liquid, i.e., oil, gas, and water. The three components have differing densities, allowing them to stratify while flowing slowly — gas on top, water below, and oil in the middle. Sand and other materials will also settle to the bottom of the separator.
  • Cryogenic vessels and ultra-high vacuum – these vessels can store oxygen, argon, or nitrogen at temperatures lower than -100°F. They often serve as super cold storage units for various fluids like hydrogen and helium needed in laboratories.
  • Autoclaves – for use in the medical and food industries to sterilize equipment. These pressure vessels use steam under high pressure to kill bacteria and other microorganisms.
  • Jacketed vessels – these containers have a metal jacket around the outside of the vessel that heats or cools the contents by circulating hot water or steam between the layers.
  • Steam drums – boilers use these as a phase-separator for water/steam mixtures.
  • Deaerators – are used to remove dissolved gases from boiler feedwater.

Application Industries

Both industrial and commercial industries use pressure vessels. Some examples include:

  • Oil and gas production
  • Power generation
  • Water treatment
  • Chemical processing
  • Food and beverage processing
  • Pharmaceutical manufacturing
  • Aerospace

technician working on the welding step of a pressure vessel fabrication process

The Pressure Vessel Fabrication Process

While pressure vessels come in all manner of shapes and sizes, some of the steps in the pressure vessel fabrication process are as follows:

  1. Plate marking – mark the plates according to the specifications of the pressure vessel. This includes marking the dimensions, tolerances, welding symbols, and other essential information.
  2. Cutting and beveling – marked plates are then cut to the required size and shape. The edges of the cut plates are then beveled to prepare them for welding.
  3. Edge preparation – next is to prepare the edges of the plates for welding. This preparation includes cleaning the edges, removing any burrs, and ensuring that the edges are properly aligned.
  4. Plate rolling – a plate roller is then used to blend the plates into the desired shape.
  5. Welding – is the next step in a typical fabrication process and one of the most critical. Strict adherence to ASME standards is required to ensure the welds are of the best quality and not a weak point for possible containment failure.
  6. Heat treatment – the welded plates are then heat-treated to relieve any stresses induced during the welding process.
  7. Hydrostatic test – hydrostatically testing the pressure vessel comes next to ensure that it is leak-free.
  8. Dimensional check – the pressure vessel is then checked for dimensional accuracy.
  9. NDE – the next step is to perform non-destructive pressure vessel testing, verifying that the pressure vessel is free of defects.
  10. Paint and coating – metal or composite coatings may be applied to protect against corrosion. Paint may be added for aesthetics, operational guides, or safety warnings.
  11. Final inspection – the pressure vessel then undergoes rigorous inspection to ensure it has met all design specifications and ASME standards.

Contact the Experts

Heartland Repair & Coatings has decades of experience constructing pressure vessels, process piping, and other structural fabrications for the oil and gas industry and others. We have ASME U Stamp, R Stamp, and NB Stamp certifications and build and repair ASME code and non-code vessels. Contact us today for your pressure vessel fabrication needs!