I think there are also differences in allowable high temp stress ( creep) , vulnerability to hydrogen damage, and in tempering treatment- also a difference in geographical popularity
shahdadf;
Yes. The difference between Cr-Mo and Cr-Mo-V steels as mentioned in the above posts can be compared using a recognized boiler and pressure vessel code of construction (like ASME B&PV Code or other international standard). You did not mention the use of the vessel. In this case, a good design approach is to use a boiler and pressure vessel construction code or one of the API codes.
In ASME B&PV Code, Section II, Part D, there are published allowable stress values as a function of service temperature for various grades of materials. My advice is to review this section and work with approved code of construction materials.
In general, the Cr-Mo-V steels have higher allowable stress values with increasing service temperature, in comparison to Cr-Mo steels because of the vanadium alloy addition. The higher allowable stress translates into thinner vessel wall thickness and ultimately less weight.
However, as also mentioned in one of the posts above, you need to know the process conditions of the vessel in service, and understand the limitations of the various grades of steel that you are considering. Selection of a suitable grade of steel in a vessel needs to be done with caution and materials/welding engineering expertise.
