Alright, here is my crack at your micro-scratch steel material.
The main take away of the material that I noticed is that the scratches should pop out right? So that means giving your micro scratches a higher Ior than the rest of the base metal. So in this case base IOR map and the bump map are the same. If you notice in your examples there is a higher IOR around the edges, so i nested this within a corona AO map with inside mode on.
I then used another different scratch map to give variation in the glossiness, nested into a fall off map so it is more glossy in grazing angles.
I then use the dirty grunge map and remapped it to give it some yellow tinge, with a gradient ramp using map mode and nested that in falloff map to plug it in the refl color slot, to give more variation.
Hope this helps!
NOTE: ALL the maps I used, were not used as is, I heavily modified them using color map adjustments in the output tabs of the maps.
