Not sure what u r looking for exactly and can't say I'm an expert but hope this helps or at least gives some ideas+I like to learn new stuff if anyone else knows any good ideas...
First I made a new document of 1000x1000pixels.
Then I made a new layer filled 50% grey.
--To this later, noise>add noise (80%, monochromatic, gaussian)
--Then blur>motion blur (160 pixels, -45 degrees)
--(You can adjust contrat/levels if you want)
That's the brushed metal layer.....
For scratches I made a new layer.
--Use brush at 1 pixel to randomly draw some squiggles/scratches in black.
--Then go to layer>layer style...Check bevel/emboss...style emboss, smooth...direction, down...depth 1%...size and soften 0.
--Then play with lighting to get shadows u want. also i made gloss profile bevel shape the curve like a backward L instead of straight flat one...4th over from top left
--Set layer mode to "lighten"
For bumps I made a new layer
--Fill black
--artistic>sponge w/ values brush size 0, definition 25,smoothness 1
--stylize>emboss>height 2 pxls, amount 100%
--set layer to "lighten" opacity 50%
For lighting I made a new layer.
--Then I used the polygon lasso tool to select an area about the size I wanted brighter.
--Then select>feather>60 pixels
--Then fill white
--Then set layer to "soft light" opacity 75%
Then I resized the whole image to 500x500 pixels so the details would be finer. Then I cropped the image cuz the edges aren't as blurred as the rest. Then I "merged visible layers" Then I cut out NETO Then I bevel embossed w inner bevel etc. and added black background!!!!
Voila!!! Sounds complicated but only took like 5 minutes or less--longest part was typin it!!
Maybe not the greatest/most advanced but thought I'd help....I love learning new photoshop things
