there is no level of industrialization where you all of a sudden check a flag for "industrialized", so asking how long did it take isn't really an answerable question. In terms of comparison to the US, it never came close to catching up to the US in industrial production or sophistication. Something like parity was achieved in a few small areas of great strategic value, but only by devoting a truly immense share of soviet GDP into prestige areas like jet engines and rockets. Almost everywhere else, they not only lagged far behind in both quantity and quality, they lost ground almost continually from the 50s onward.