Acceptable tolerance for surface defects on pressure piping

[Mech 3D]

Hello Engineering Family,
I have a 6 inch stainless steel SAF2205 which operates at 40bar and 220 degrees Celsius.
During NDT inspection of the new pipe I found a surface crack , and I had to cut through a groove 2mm deep to check how far the crack is but beyond that the pipe is fine.
Is this pipe acceptable with a 2mm groove or I need to reject it? Any standard I can use?

 

[SWComposites]

How thick is the pipe wall?
2mm deep sounds really bad. Why not just weld the crack?

 

[LittleInch]

How do you know beyond that it is fine?

Is it cracked from both sides?

Have you dye pen tested the cut out?

But for Stl Stl 2mm defect is pretty significant as it the size and length of the groove you have created (no pictures or details provided)