Deaerator material substitution
Thread Content
Can the material Q235-B of the deaerator be replaced by Q345?
There seems to be no problem, why not?
There is a problem with what the poster said. There are two types of deaerators: high-pressure and low-pressure. Generally, the working pressure of low-pressure is 0.02 MPa, which is not a vessel subject to supervision. The general working pressure of high-pressure is 0.5 MPa. In this case, it is within the scope of supervision. If it is a pressure vessel subject to supervision, it is inappropriate to use Q345 instead of Q235-B, and Q345R should be used instead.
On the premise of meeting the usage requirements (such as anti-corrosion requirements), the basic principle of material substitution is: You can only replace low with high, not high with low.