Based on the mathematical method of queuing theory, the queuing model of billets in the direct rolling process of the long product was established, which represented the conveying process of billets at the casting and rolling interface. Using the billets queuing model, the influence of different steel quantity, length, speed and other factors on the average waiting time of a single billet in the direct rolling production process was analyzed. Combined with the temperature drop of billets, the optimal average waiting time for a single billet was determined. The method improved the conveying connection efficiency of the casting-rolling interface and the direct rolling rate of billets.

In this work, the forging process of ultra-high strength stainless steel has been simulated based on Simufact Forming. The simulation results show the temperature drop at the ends of the workpiece is obvious, and the strain is difficult to penetrate. Affected by the shape of the workpiece, the strain is mainly located on the surface during the first and second passes of stretching and chamfering, while the strain penetrates toward the center in the middle passes of stretching. It is noted that the degree of dynamic recrystallization (DRX) of center microstructure is insufficient due to the strain is slightly larger than the critical strain of DRX. Affected by temperature field and strain field, dynamic recovery is the main softening mechanism during radial forging.