How are PED Pressure Vessels Manufactured?June 19, 2017
Pressure Equipment Directive or PED is a standard set by the European Union (EU) for the design and fabrication of pressure equipment. The standards that are set in the directive are very close to those defined by the American Society of Mechanical Engineers (ASME). This allows several international inspection agencies to verify and certify pressure equipment, and check whether they conform to the pressure equipment directives. With this in mind, several pressure vessel manufacturers have started manufacturing the equipment in compliance to the PED. How are the PED pressure vessels manufactured? Please read the following post to get knowledge about the steps involved in the manufacturing process.
Steps Involved in PED Pressure Vessel Manufacturing
There are a number of steps involved in manufacturing pressure vessels that conform to the PED standards. Here are they:
- Forming: This is the first step of manufacturing. Forming refers to changing the shape of a part by applying a force. Forming can be carried out at three different temperature ranges, namely:
- Cold Forming: As the name suggests, this type of forming is carried out at a fabrication temperature, which is extremely low than the materials recrystallization temperature (it is the minimum temperature at which deformed grains get replaced by new grains that are undeformed).
- Warm Forming: This is the middle range, where the fabrication temperature is above the room temperature, yet lower than the material’s recrystallization temperature.
- Hot Forming: Hot forming is the process in which the fabrication temperature is very much above the material’s recrystallization temperature.
- Pressing: The name says it all. Pressing is the process in which the required part is given the desired shape with the help of a pressing machine.
- Spinning: This is the next step after pressing. The end of a pressure vessel or head is given the desired shape with the spinning process. The spinning machine has adjustable rollers, with which the material is formed till the desired shape is achieved.
- Bending: Bending, which is also referred to as rolling, is a process in which the material is given curves of desired radius. This process makes use of bending machine.
- Welding: The bending process is followed by the welding process. You must be aware of welding. It is the process in which two or more materials are melted to join them permanently.
- Post Weld Heat Treatment (PWHT): This is one of the most important steps involved in the manufacturing of pressure vessels. In this step, it is checked whether material strength of the part formed is retained. In this process, the residual stress introduced in the material by welding is reduced and redistributed by applying heat treatment. This helps improve the properties of the weldment.
- Assembly: As the name implies, assembly refers to the process of joining the pressure vessel parts together.
- Painting: This is the last step in the manufacturing process in which paint is applied to the final product to protect it against corrosion.
All the above referred are the steps involved in the manufacturing of PED compliant pressure vessels. The pressure vessels that are manufactured by following these steps have a longer service life. There are a number of manufacturers, who manufacture pressure equipment following the guidelines set in the PED directives. One such company, which can help you with your pressure vessel requirements is BEPeterson. The company is ASME and ISO 9001:2015 certified, and makes use of advanced techniques in manufacturing and delivering high quality equipment to its customers.