There are countless places and times you can use metal textures. Many tutorials will show you how to make metal, but this tutorial will go into more detail to show you how to make your metal unique.
Creating the Metal
There are hundreds of tutorials about how to make metal in Photoshop. Hopefully this one will show you how to make your metal unique.
Open a new document. I chose to make mine 800 by 500.
Go to Filter > Noise > Add Noise (Use the settings in the picture below)
Now go to Filter > Blur > Motion Blur
The settings on this may vary depending how you want you metal to look, and it will vary because of canvas size.
I used an angle of -30 and a Distance of 270.
Duplicate the layer. Select the top layer and go to Image > Adjustments > Hue/Saturation (Ctrl-U). Click the check box that says “colorize“. You can set the Hue to whatever you want, but the saturation should be between 30 and 50 and lightness should be left at 0.
To make your metal unique you can make scratches in it, or you can even make bullet holes.
To make scratches use the dodge and burn tools. Pick a small brush and go to town.
To make bullet holes just copy this picture
and paste it into a new document.
Next go to Edit > Define brush preset… Name the brush and you should be done.
Here is my final version…