Introduction to boilers and pressure vessels

Boilers and pressure vessels are sealed vessels used to hold liquids or gases under pressure.Although theoretically pressure vessels can be of any shape, they are usually spherical, cylindrical, or domed.In other words, most pressure vessels are cylindrical, with a 2:1 half  semi-elliptical  head or end cap at each end.

Smaller boilers and pressure vessels are made of pipes with end caps,while larger vessels may be made by welding several rolled or possibly forged parts or components.Regardless of the construction method used, boilers and pressure vessels are designed to strict Australian standards and many require regular checks to ensure safety.

Forged steel flange hydro pressure test

Forged steel flange hydro pressure test

Where are boilers and pressure vessels used?

There are many uses for boilers and pressure vessels both in industry and the private sector. Here are just a few examples:

  • Diving cylinders
  • Domestic hot water storage tanks
  • Compressed air storage tanks
  • Passenger cabin of an aircraft
  • Recompression chamber
  • Gas nuclear reactor
  • Industrial boiler
  • Road tanker
  • Petrochemical storage and transport tanks

Why do boilers and pressure vessels need specific plate steel?

There are many factors to be considered in designing boilers and pressure vessels.These factors include the size and weight of the vessel and what’s contents, internal and external forces, ambient and operating temperatures, pressure, corrosion and so on.Under these special operational requirements, it makes sense to use safe and effective design materials.

Boiler and pressure vessel grade steel comes in a variety of grades and thicknesses, and are designed to withstand the immense internal pressure. These grades are fully killed, fine grained carbon-manganese steels produced by hot rolling and normalizing. Importantly, these steel grades are designed to leak before burst.

There are many grades to choose from.Boilers and pressure vessels have different grades of steel, different thicknesses and different uses.For example, some types of steel have high temperature properties.