steel tub warpage

I have a steel tub and have recently noticed two small bumps, about a quarter in size each. They are in the the same general area of the tub. Is warpage possible with a steel tub? Is something I should be concerned about? Or is this more likely a defect from the manufacturing process?

tub

For all practical purposes, in the long run, a steel tub is just one big defect. But your problem is probably rust causing the enamel to come loose and bulge. The tub itself cannot warp like that.