The SAT is not curved, CB uses an equating process to adjust scores.
Equating is Not Grading on a Curve
Some students and parents confuse “equating” with “grading” on a curve,” but it’s not the same thing. When a test is scored on a curve, the score may change depending on how everyone
else performed on the test. A student’s SAT score is based only on how they perform and is never affected by another student’s performance.
The equating process is described here: https://satsuite.collegeboard.org/media/pdf/sat-scoring-equating.pdf