Dynamics of exit section of automatic mill of pipe rolling line

Nonuniformity of pipe wall thickness is one of significant indices, determining quality of hot-rolled seamless pipes. One of the reasons of increased nonuniformity arising is dynamics of exit section mechanisms of pipe rolling line (PRL). Results of study of mandrel holding mechanism dynamics of PRL presented. Dynamic models of exit section, accounting parameters of technological process and inertia of a rolled hollow billet elaborated, which enabled to determine the character of dynamic processes at the exit section of PRL automatic mill. Differential equations of exit section elements motion at the exit section of PRL automatic mill were made up. The solution of the differential equations system was obtained in a numerical form by application of Runge‒Kutta method for correspondent dynamic models of exit section based on the example of calculations for ТПА-350 automatic mill. The pattern of dynamic processes arising at the exit section was specified at realization of the whole technological process of a hollow billet rolling at automatic mill, taking into consideration alternative action from the side of deformation center and mass of the rolled hollow billet. It was shown, that the specified solution of the task for three advanced dynamic models of mechanical system considerably differs from those of the known mathematical models. It was established, that the dynamics of the mandrel holding mechanism of ТПА-350 automatic mill equivalently form the mechanism of finished pipes geometry forming. Analysis of dynamic models of the mill exit section enabled to select the necessary technological and dynamic parameters of the mechanical system, to determine stable modes of hollow billets rolling at the ТПА-350 automatic mill. Results of the study of dynamics of exit section ТПА-350 automatic mill presented. A scheme of modernization of the exit section ТПА-350 automatic mill proposed, which enables to realize rational modes of operation accounting level of mechanical system dynamics and to control quality (geometric parameters) of the rolled pipes.

Research on Production Technology of Asymmetrically Hot Rolled Stainless Steel Clad Plate

The hot rolled single sided stainless steel clad plate of 316L stainless steel and Q345C steel was carried out in a hot rolling line by the technology of “electron beam vacuum welding and hot rolling”. High quality single sided stainless steel clad plates were produced by asymmetrical compound billet and asymmetrically rolling. The productions of stainless steel clad plate have reached the requirements of GB / T 8165-2008. The interface shear strength is greater than 320 MPa. The yield strength is greater than370 MPa. The tensile strength is greater than 520 MPa. The elongation is greater than 30%, A good metallurgical bonding between stainless steel and carbon steel was achieved. The bonding rate reached 100%. The composite interface is straight and perfect. The pilot production in the study has laid down the certain basis for the production of the single-side dissimilar-material composite board.

Design of pure rolling line gear mechanisms for arbitrary intersecting shafts

Design of pure rolling line gear mechanisms for an arbitrary angle intersecting shafts was presented in this article. Based on the active design method of meshing line function for orthogonal shafts, three meshing types of conjugated tooth surfaces for an arbitrary angle intersecting shafts were discussed, including the parametric equations of different generatrix circles, the mathematical models of tooth surfaces, and central curves to be constructed, respectively. The validity of the active designed meshing line function was verified according to meshing equations, and the theoretical sliding rations were analyzed to prove pure rolling meshing. Then basic design parameters of pure rolling line gear mechanisms for the geometry design were determined, and the main structural parameters were obtained therefrom. Lastly, three groups of numerical examples were proposed according to mathematical models. Resin samples of line gears were processed by rapid prototyping technology and the kinematic performance of the pure rolling line gear mechanisms were validated. This paper laid the foundation of geometry and parameter design for pure rolling line gear mechanisms for an arbitrary angle intersecting shafts.