The Manufacturing Process of Spherical and Cylindrical Pressure Vessels

Pressure vessels play a vital role in various industries, including refineries, power plants, and mines. Due to the high risk of working in these industries, manufacturers are obliged to observe certain points in the construction stages of pressure vessels.

Since the fluids inside these tanks are all under pressure, any small flaw in the construction can lead to irreparable problems. In this article, we will examine the various methods and design principles of this equipment.

Methods of making spherical and cylindrical tanks under pressure

The ASME SEC VII standard is known as the main standard for the construction of spherical and cylindrical pressure tanks. This standard provides two main methods for manufacturing pressure vessels:

  1. Welding:

In this method, first the base metal is selected and calculations related to tank design are performed. Then, according to the application of the tank, the appropriate welding method is selected. Types of welding include:

  • Manual electrode welding
  • Mag boil
  • Sub-powder welding
  • Tig Boil

In this method, the body of the tank is first rolled and then its cap is made separately. Then, using welding, different parts are connected to each other.

  1. Forging:

Forging is a type of welding method that is used in the production of cylindrical and spherical tanks under pressure. In this method, two metal sheets that need to be connected to each other are placed next to each other. Then by applying a lot of heat, the junction of the two sheets becomes a paste, and finally, by pressing together, the connection between the sheets is established.


Pressure tank construction steps

After getting acquainted with the construction methods, we will examine the construction steps of pressure vessels one by one:

  1. Material used in the construction of pressure vessels

The type of material used in the production of pressure vessels is very important. The selected material will have a great effect on the reliability and safety factor of the tank. The main ingredients include:

  • Titanium
  • nickel
  • stainless steel
  • aluminium
  • Carbon steel
  1. Pressure tank design and calculations

At this stage, design software such as Ansys is used. Calculations include thickness, strength, design pressure, and design temperature. It is essential that safety considerations, material selection, and pressure type are observed during calculations.

  1. Construction of pressure vessels

After complete calculations, the necessary equipment for construction is obtained. Welding or forging methods are used and the body of the tank is made along with fittings and other parts.

Conduct safety testing

Design Principles

In the design of pressure vessels, it is necessary to follow the basic principles. Appropriate wall thickness, tight connections, and safety against high pressures are among the most important points. Also, choosing the right material according to the chemical and physical characteristics of the fluids inside the tank plays a vital role.

Attention to standards

Compliance with standards, especially ASME SEC VII standard, is essential in the construction of pressure vessels. These standards provide guidelines and methods for implementing various manufacturing steps and provide a point of credit for safety and quality.

Specialized cooperation

The production of a pressure tank requires the specialized cooperation of experts in different fields. Material science experts, mechanical engineers, and non-destructive testing experts can work together to build a high-quality and safe tank.

Sustainable growth of the pressure vessel industry

The pressure vessel industry has achieved steady growth due to its vital role in many industries. But paying attention to technical points, safety, and current standards allows building high-quality and confident tanks.


In general, the construction stages of pressure vessels require the specialized cooperation of experts in different fields. This article tried to point out in a general way the various methods and stages of pressure tank design and construction. In the end, the importance of observing technical and safety points in all stages of pressure tank construction is obvious. The collaboration of experts in various fields, including materials science, non-destructive testing, and mechanical engineering, is essential to ensure the optimal performance and safety of tanks.

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