Top tip of the day™ - Metallic (or electrically conductive) objects have a colour specular map, generally a similar colour as the diffuse. Non-metallic objects tend to have a white specular map (or even an inversed diffuse map in the spec'). :)
It's definitely a step in the right direction, but I think the red colour of the pipes is darkening the scene somewhat. Remember that the Diffuse texture of a material is what colour it will be when fully lit, so a dark texture will only ever be dark, no matter how much light you shine on it. Add this to your naturally…
Cool, do those barrels have a spec map? You could probably slightly reduce some of the overlays from the diffuse and instead crank the contrast in the spec to get a more metallic look. It's a bit too matte at the moment. Also be sure to pipe a value into the Spec Power / Glossiness node that's higher than the default 15. I…