P355GH steel and Q345R steel difference

P355GH steel and Q345R steel are two steels commonly used in the manufacture of pressure vessels, and the differences between them can be compared in detail in a number of ways:

1. Standard:
P355GH steel: in line with the European EN 10028 standard, mainly used for high temperature and high pressure pressure vessels.
Q345R steel: in line with China GB713 standard, used for general pressure vessel manufacturing.

2. Chemical composition:
P355GH steel: contains higher alloying elements such as chromium, molybdenum and manganese to improve its high temperature resistance.
Q345R steel: mainly composed of carbon structural steel, high carbon content, generally low alloy steel.

3. Mechanical properties:
P355GH steel: with high tensile strength and yield strength, suitable for high temperature and high pressure environments.
Q345R steel: Generally has low tensile strength and yield strength, suitable for low to medium temperature and general pressure vessel applications.

4. Use temperature range:
P355GH steel: Suitable for the manufacture of pressure vessels under higher temperature conditions, usually operating temperature above 300 degrees Celsius.
Q345R steel: suitable for the manufacture of pressure vessels under general medium and low temperature conditions, and the working temperature can be lower.

5. Welding performance:
P355GH steel: has good welding properties, easy to achieve high quality welding.
Q345R steel: also has better welding performance, but there may be some differences compared with P355GH.

6. Corrosion resistance:
P355GH steel: Due to its high alloying element content, it has good corrosion resistance.
Q345R steel: It has certain corrosion resistance under general conditions, but it is not as superior as P355GH steel.

The choice of P355GH steel or Q345R steel should be determined according to the specific engineering needs and working conditions to ensure compliance with relevant standards and safety requirements.