During rolling steel AISI1008 for claw machine in rolling line of steel bar

the mixed crystal phenomenon occurs. The ferrite grain size rating at the edge

1/2 radius and center of Φ50 mm rolled bar is respectively 3

8 and 8. Through metallographic and electron microscopic examination of round steel

the finite element simulation of finish rolling temperature and equivalent strain is carried out by using Deform software. It is found that the cause of coarse grain size at the edge of round steel is related to the low finish rolling temperature and the large equivalent strain during rolling. With improvement measures to increase the finish rolling temperature from 820°C to 880°C

the uniformity of section grain size of round steel is successfully improved.