Mechanism of and Key Technologies for Copper Bonding in the Hot Rolling of SCR Continuous Casting and Rolling

In the process of copper alloy hot continuous rolling, the problem of copper sticking to the roller seriously affects the surface quality, performance, and service life of the copper products. Roll sticking occurs as the adhesion energy of Cu is lower than that of Fe and the Fe-Cu interface, and the severe surface deformation which forces the copper into direct contact with the roll during the process of profile rolling. Based on the copper deformation law and adhesion phenomenon in the hot continuous rolling process, a rolling deformation model and roll copper adhesion model or copper alloy hot continuous rolling were established, and their simulation was realized using finite element software. Through finite element modeling of the hot rolling deformation zone, the distribution of the temperature, contact normal stress, and exposure rate in the hot rolling deformation zone were obtained, which were consistent with the actual roll adhesion phenomenon and copper adhesion position. To address the copper sticking behavior of the rolls, the process optimization method of matching the motor speed with the elongation coefficient (the 1# and 2# motor speeds were adjusted to 1549 r/min and 1586 r/min, respectively), adjusting the roll gap to 7.9 mm, and increasing the number and pressure of roll spray nozzles were put forward, which effectively solved the problem of copper sticking to the roll, significantly improved the surface quality of the copper and the service life of the roll, and can be used in production.

Rolling Force Prediction of Hot Rolling Based on GA-MELM

In the hot continuous rolling process, the main factor affecting the actual thickness of strip is the rolling force. The precision of rolling force calculation is the key to realize accurate on-line control. However, because of the complexity and nonlinearity of the rolling process, as well as many influencing factors, the theoretical analysis of the traditional rolling force prediction model often needs to be simplified and hypothesized. This leads to the incompleteness of the mathematical model and the deviation between the calculated results and the actual working conditions. In this paper, a rolling force prediction method based on genetic algorithm (GA), particle swarm optimization algorithm (PSO), and multiple hidden layer extreme learning machine (MELM) is proposed, namely, PSO-GA-MELM algorithm, which takes MELM as the basic model for rolling force prediction. In the modeling process, GA is used to determine the optimal number of hidden layers and the optimal number of hidden nodes, and PSO is used to search for the optimal input weights and biases. This method avoids the influence of human intervention on the model and saves the modeling time. This paper takes the actual production data of BaoSteel 2050 production line as experimental data, and the experimental results indicate that the algorithm can be effectively used to determine the optimal network structure of MELM. The rolling force prediction model trained by the algorithm has excellent performance in prediction accuracy, computational stability, and the number of hidden nodes and is applicable to the prediction of rolling force in hot continuous rolling process.

Fe-Simulation of Hot Continuous Rolling of 40Cr Alloy Steel Round Bar and Roll Pass Design

40Cr alloy steel is widely used in the mechanical manufacturing industry and the quality of its rolled round bar has a great consequence on the quality and useful time of the final mechanical parts. By analyzing the characteristics of thermal plasticity of 40Cr steel, the Hensel-Spittel flow stress model of 40Cr steel was established in this study. For the possible continuous rolling schedule of Φ80mm 40Cr steel from 200mm×200mm billet, the advanced technology of viscoplastic FEM by LARSTRAN/SHAPE was used to create 3-D thermo-mechanical coupled simulation models for 8-pass hot continuous rolling processes. From the rolling process simulation the stress, strain, temperature distribution and rolling force variation were obtained. The simulation results included the comparison of plastic deformation of round pass with curved side wall and round pass with straight-side wall as well as the cause of rolling defect (e.g. crack). Based on the numerical analysis the reliable roll pass sequence wa constructed, which was verified by actual tests.

Study on Metal Flow in the Finish Rolling Process of Large-Sized H-Beam

According to the production data of a rolling H-beam factory, the FE model of hot continuous rolling process of H-beam is built. With the FEM software of DEFORM-3D, the continuous rolling of H-beam was simulated. On base of simulation result, the metal flow and deformation law are discussed. Because of the flange and web is deformed in the different deformation zone, the metal flow law of flange and web is complex, especially the metal of the conjunction of flange and web. In this paper, the metal flow of large-sized H-beam in finishing rolling process is analyzed.