The basic factors relating to the rheological stress in the constitutive equations were introduced. Carbon constructional quality steels were regarded as a kind of elastic-viscoplastic materials under high temperature and the elastic-viscoplastic constitutive models were summarized. A series of tension experiments under the same temperature and different strain rates, and the same strain rate and different temperatures were done on 20 steel, 35 steel and 45 steel. 52 groups of rheological stress—strain curves were obtained. The experimental re...