Decal effect help please

Hi guys
I’m new and don’t know much yet. Please tell me how it’s done.
Used bump offset? There are several rings on one crack, each ring has its own welding speed?
Please tell me how to repeat this in Unreal.

It looks very much like bump offset. I’ve done something similar in my last unreal project (in the description you can find my project file to download and inspect the material):