Possible reasons:
Surface damage or contamination of the rolling mill.
Poor lubrication during rolling process.
Improper annealing or pickling process (such as corrosion caused by residual acid solution)
The storage environment is humid, causing oxidation of molybdenum sheets.

Resolvent:

Before rolling: Ensure that the rollers are clean and undamaged, and use high-purity lubricants.
After annealing: thoroughly clean to remove acid residue, and protect annealing with vacuum or hydrogen gas.
Storage: Sealed moisture-proof packaging (vacuum/inert gas), avoid exposure to air.

Possible reasons:
Uneven tension during rolling.
Uneven heating during annealing.
Residual stress not released.

Resolvent:

Adjust the tension control system of the rolling mill
Adopting uniform heating annealing process (such as slow heating)
Add straightening process (such as roller straightening)

Possible reasons:
Insufficient precision of the rolling mill or wear of the rolling mill rolls
Unstable rolling force control
Uneven original thickness of materials (such as hot-rolled billets)

Resolvent:
Regularly calibrate the rolling mill and replace worn rollers
Optimize rolling process (such as multi pass light rolling)
Real time monitoring using high-precision thickness gauges