A centralizer sub for cementing a tubular string in a wellbore includes: a tubular body; a centralizer disposed along an outer surface of the body and having a pair of collars and a plurality of bow springs connecting the collars; and a joint longitudinally linking the centralizer to the body. The joint has: a groove formed in and around the body outer surface, and a plurality of protrusions formed integrally with or mounted to one of the collars and extending into the groove.