Influence of pass spacing on the spinning process of nickel-based alloy conical casing

High temperature nickel-based alloys are prone to forming defects due to serious work hardening, and the pass spacing is an important parameter in multi-pass drawing and spinning. Using GH4169 superalloy as the material, a Finite Element Model (FEM) was established based on the Simufact platform, and the influence of the pass spacing on the spinning process was explored by using the concave curve and circular arc trajectory. The results show that the stress-strain increases with the increase of the pass spacing. Obtain the optimal pass spacing under specific conditions: blank wall thickness t = 2,5 mm, blank diameter d = 250 mm, feed ratio f = 1,2 mm/rad, mandrel speed n = 300 r/min, pass spacing p = 14 mm

Geometric phase and quantum phase transition in an inhomogeneous periodic XY spin-1/2 model

The notion of geometric phase has been recently introduced to analyze the quantum phase transitions of many-body systems from the geometrical perspective. In this work, we study the geometric phase of the ground state for an inhomogeneous period-two anisotropic XY model in a transverse field. This model encompasses a group of familiar spin models as its special cases and shows a richer critical behavior. The exact solution is obtained by mapping on a fermionic system through the Jordan-Wigner transformation and constructing the relevant canonical transformation to realize the diagonalization of the Hamiltonian coupled in the $k$-space. The results show that there may exist more than one quantum phase transition point at some parameter regions and these transition points correspond to the divergence or extremum properties of the Berry curvature.Comment: 6 pages, 3 figures. As a backup of a previous work and some typos in the published version are fixe

Effect of process parameters on microstructure of 42CrMo steel ball hot skew rolling

Microstructure grain refinement is an effective way to improve the quality of 42CrMo steel ball. A three-dimensional thermal-mechanical-microstructure coupled Finite element model (FEM) of steel ball skew rolling is established in the finite element simulation software. Simufact software was used to simulate the effects of process parameters on the microstructure of steel balls, and the effects of roll Angle, roll temperature and roll speed on the average grain size of rolled pieces were analyzed by single factor variable method. The research results provide some reference for the improvement of 42CrMo steel ball quality

Effect of miR-146a/bFGF/PEG-PEI Nanoparticles on Inflammation Response and Tissue Regeneration of Human Dental Pulp Cells

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Formation mechanism and control of the spiral marks of three-roll skew-rolled hollow axles

The spiral marks is one of the main surface quality defects of the three-roll skew rolled hollow axles. In order to eliminate the spiral marks, it is necessary to clarify the cause of the spiral marks on the surface of the rolled piece. Based on the analysis of the kinematics of the three-roll skew rolled hollow axles, the spiral marks is caused by the spiral pitch of the rolled piece being larger than the width of the finishing section of the roller. Increasing the rotation speed of the roller can reduce the spiral pitch of the rolled piece, thereby avoiding the appearance of spiral marks. The correctness of the proposed condition for preventing the defect of spiral marks is verified by simulation

Effect of process parameters on the force parameters in warm skew rolling of copper ball

In order to better control the forming quality of copper ball by warm skew rolling process, a Finite Element Model (FEM) of copper ball warm skew rolling for the coupling of thermal and mechanical was established. The influence of process parameters on force and rolling torque was analyzed by using single factor research method. The results show that the smaller the cross angle, the lower the rolling temperature, the slower the rolling rotation speed, the greater the forming force and rolling torque, the more difficult for forming. The optimum rolling temperature is 600 °C; the optimum cross angle is 2,5°; the optimum rolling rotation speed is 60 rpm