Abstract: The microstructure and mechanical properties of pseudo-eutectoid steels with different carbon contents after warm rolling were studied by SEM and tensile tests.The results show that the ferrite in the pseudo-eutectoid steel after hot water quenching decreases with the increase of carbon content, and the pearlite content increases.After being warm-rolled at 500℃, the ferrite in 35 and 45 steel is distributed in strips along the rolling direction, while the ferrite in 55 steel is distributed in intermittent strips.In addition, the degree of cementite fragmentation in 55 steel is the largest, and the distribution of cementite is also the most dispersed.Compared with 35 and 55 steels, the degree of cementite fragmentation in 45 steel is the smallest.With the increase of carbon content, the strength of the steel increases and the plasticity decreases.The 55 steel with the highest yield strength can reach 1308MPa, and the 35 steel with the highest average elongation can reach 6.4%.But in terms of overall performance, the strength-to-plastic ratio of 45 steel is best, and its performance even reaches the level of low-alloy steel.