Could Soviet industry make battleship armor?

Would the Soviet Union develop its own battleship armor, or buy it abroad?

It could buy armor abroad, but Stalin would likely force domestic production, and foreign planners would still have to treat the ships as credible threats.

Stalin would probably prefer domestic armor even if quality proved uneven. Czechoslovak, Swedish, or American suppliers offered alternatives if Soviet production fell short. Rival navies could not safely assume that Soviet armor would fail in combat. Force planning has to answer a claimed capability instead of hoping that an opponent is incompetent or lying.