Getting decent looking aluminium plate in my renderings is something I have been trying to do for a while now, I am quite happy with what I have come up with. Although in a months time I’ll probably change my mind. Starting out I was determined to use procedural textures, as too many image maps really bog the scene down. And I already have a 4k image for my water surface.
The first was to add an anisotropic shader, which was pretty straightforward, although it can only be added in cycles. I used my UV map to indicate the direction that the striations will run in, and that was about it.
Next was to add a brushed metal look, which I got using the musgrave texture, first mapping it to stretch the texture out, and then dividing it to compact it Here is a close-up where I have exaggerated the look.
Next up I decided to add some water marks, very subtly, to make the material more life-like. Once again the musgrave texture node did the trick. Here it is exaggerated:
After playing with all the values it was still looking a bit harsh, and adding a Fresnel node connected to the factor channel in the mix node gave a softer result. So in the spirit of giving back, below is my complete aluminium sheet metal shader.
Backstay Design 