Industrial boilers are found in a variety of industries including petrochemical, power generation, and production plants.
Like pressure vessels, industrial boilers are designed to work at above atmospheric pressure with steel being the material of choice due to its workability and durability. The grade of steel used for industrial boilers does not however require the higher yield strength of pressure vessels. The choice of steel grade for use in any pressurized environment is an important one, and the use of steel in industrial boilers is no exception.
Essentially, pressure vessels and boilers the same. The main difference tends to be historical and due to how boilers are used. Historically, industrial boilers are limited in performance by the temperature level at which water boils (steam generation). Pressure vessels work at much greater pressure and the steel used has greater yield strength.
About Boiler Steel Plate
Boiler steel plate is a high quality steel, produced at the steel mill to a very high quality which is designed to withstand the internal pressure in boilers and valves. Boiler steel is a popular material due to its longevity and diversity of use.
Boiler steel supplied to both the ASTM and ASME standard are available are available for supply on a global basis form specialist steel stockholders. The main grades of steel suitable for use in the fabrication of industrial boilers include:
- ASTM A516 Grade 60
- ASTM A516 Grade 65
- ASME SA516 Grade 60
- ASME SA516 Grade 65
Boiler steel plate can be supplied in a variety of plate widths and thicknesses and can be cut to sizes to suit. Boiler steel can also be tested for susceptibility to the effects of hydrogen induced cracking (HIC) where the build up of hydrogen sulphide can potentially cause the boiler to fail. As the boiler is a stressed tank, such a failure could cause potential injury.
Other testing available may include:
- Charpy V Notch Impact Test – testing a steel specimen to the point at which it breaks
- Ultrasonic Testing – testing the steel plate ultrasonically
- Magnetic particle examination
- High Temperature Tension Testing – testing of the steel at elevated temperatures
The above test examples in many cases can be transported out by the steel mill itself or a third part testing organization as arranged by the customer. Plates are shipped with test certification and stamping on the plate providing full traceability.