That looks fantastic, and the grain really adds to the metal finish.

Though, I think you should've maybe darkened the background, before drawing it, with charcoal or a very soft pencil and then smudge it out so it becomes relatively smooth, maybe with a gradient so it's darker at the bottom. As this would really show the contrast in the image, as the total white-ness of the background is quite distracting somehow and doesn't work with how dark the shadows are.
But I know how much work getting a background like that would be, just a thought on how the image would really "pop".

But nonetheless, absolutely fantastic.