I did an EPC Chinese project in 2002, and I still keep Chinese code GB150-1998.
Here are the properties from Chinese code
- Q235A and Q235B have the same tensile and yield: 375/235 Mpa
- Both have the same allowable stress from ambient to 350C.
The differences of A and B when using as vessel plate:
Q235A: design pressure 1.0Mpa maximum, 16 mm thick maximum
Q235B: design pressure 1.6Mpa maximum, 20 mm thick maximum
Both shall not be used in toxic substances. Q235A shall not be used in liquefied petroleum gas.
So looks like B is better than A, though they have the same mechanical properties.
The Chinese project manager told us AQ235A is equivalent to : SA-283-C, SA-36, SA-307B.
So if you treat Q235B as the above, you shall be good to go, and I am pretty confident for it.