Peculiarities of calculations of formation of extended sections of steel castings in disposable moulds with functional coating of definite microrelief

In the present article are considered the issues of influence of the microrelief of the working cavity surface of the sand-and-clay mould on the intensity of heat exchange and formation of the structure in the surface area of the metal blank, for prevention of hot cracks formation.

LOAD PREDICTION ON METAL FORMING PROCESS (FORGING) USING FINITE ELEMENT METHOD.

Metal forming process is a widely used manufacturing process especially in high volume metal production system. In this paper, the main objective is using Bubnov-Galerkin finite element model to derive the pressure field set up at various cross-sections of a metal blank during a forging process, and the four Lagrange quadratic elements were assembled to represent the various metal blank. The governing equation adopted for this paper is a one-dimensional differential equation describing the pressures exerted on the forging process. During the analysis, the various metal blanks are divided into a finite number of elements and the weighted integral form for each element were formed after applying the Bubnov-Galerkin weighted residual method. A matrix form under certain boundary conditions from the weighted residual method were used to obtain the pressure distribution across the cross-section of the various metal blanks. Finite element results are obtained for a value of a circular disc diameter, thickness, coefficient of friction, principal stress, length, and radius of a circular material. Finite element method and the Exact solution approach are used to achieve and compare both results. Furthermore, the combination of both methods shows that there are potentials for using this approach towards the optimization of metal forming in manufacturing processes and some engineering practices. Keywords: Forging; LaGrange Interpolation Function; Bubnov-Galerkin Weighted Residual Method; Finite Element Method.

Technology of Manufacturing of Disk Blanks to High-Speed Elements for Tests on Anti-Meteoroid Protection

In this paper, a variant of the manufacturing technology of the disk blank for the segment liner of the shape charge is proposed. The charges are used to test the anti-meteorite stability of spacecraft. The proposed method makes it possible to form a blank in which, as its thickness decreases from the center to the periphery, a periodic profile variable in thickness is formed simultaneously in the circumferential direction. The disk metal blank is fixed in a three-cam chuck and the end face of the disk is cut with a decrease in thickness along the generatrix from the center to the periphery. Under the action of fastening forces, the disk blank is deformed and after processing the thickness in the cross section has a triangular periodic profile. Experiments on processing of disk preparations at various efforts of machine device are carried out. The dependences of the disc thickness on the fastening force in the device are obtained. After harmonic analysis of the thickness of the cross section, the values of the amplitudes of harmonics of different thickness in the circumferential direction at different distances from the center of the disk blank were determined. An increase in the fastening force leads to an increase in the amplitude of the third harmonic of the part thickness. It is shown that the change in the amplitudes of the first and second harmonics of different thickness is insignificant, and the amplitude of the third harmonic increases from the center to the periphery, which is caused by a decrease in the stiffness of the workpiece in the peripheral region.

Formation of Nanostructure and Tool Wear during Cutting Treatment of Titanium Alloy

Methods of the optical metallography, TEM, SEM-technique, tests for hardness and wear resistance are used to investigated the structural - phase transformation in metal blanks from alloy VT23 at cutting treatment in an interval of speeds 2...120 m/min are given. The patterns of interaction of dynamic plastic deformation and destructions on macro-, meso-, micro-and nanolevels are determined. It is shown that the formation in metal blank of modulated high-tensile secondary nanostructures promotes a heightening of a protective wearproofity of treated metal blank, but cutting edge, lowering a wearproofity, of the cutting tool.

Analysis of the Influence of Fibers on the Formability of Metal Blanks in Manufacturing Processes for Fiber Metal Laminates

In the one-step manufacturing process for fiber metal laminate parts, the so-called in situ hybridization process, the fabrics are interacting with metal blanks. During deep drawing, the liquid matrix is injected between the metal sheets through the woven fiber layers. The metal blanks can be in contact with dry or with infiltrated fibers. The formability of the blanks is influenced by the variation of the starting time of injection. The reason for that is that, due to high contact forces, the fibers are able to deform the metal surface locally, so that movement and the strain of the blanks is inhibited. To investigate the influence of different fibers on the formability of metals, Nakazima tests are performed. In these tests, two metal blanks are formed with an interlayer of fibers. The results are compared with the formability of two blanks without any interlayer. It is shown that in with fibers between sheets, the formability decreases compared to the formability of two metal blanks without interlayers. Based on a simplified numerical model for different types of fibers, the interactions of the fibers with the metal blank are analyzed. It could be shown that the friction due to contact has more influence than the friction due to the form fit caused by the imprints.

Numerical simulation of heat exchange at cooling of high-temperature metal blank made of steel ChGSN2A

The results of the numerical simulation of heat exchange at the cooling metal blank made of steel 30ChGSN2A are shown. The velocities of blank cooling with the flow of gas-liquid medium are defined. Cooling intensity changes depending on the blank motion speed opposite the flow of cooling medium are analyzed.

Numerical and Experimental Forming of Axisymmetric Products Using Methods of Deep Drawing and Flow Forming / Numeryczne I Eksperymentalne Kształtowanie Wyrobów Osiowosymetrycznych Metodą Tłoczenia Oraz Kształtowania Obrotowego

The paper deals with the problem of forming of axisymmetric element. Two-stages process was taken into consideration: deep drawing of metal blank using hydraulic press and the method of elongating flow forming. The contribution presents results of numerical and experimental analyzes. Numerical simulations of both the processes were realized in Kraków at AGH University. Numerical verification of both processes was carried out using finite element models implemented with the help of commercial analysis system on basis of conducted in Poznań experimental shaping tests of Hastelloy C-276 alloy. The tests were aimed to find opportunities and conditions of plastic deformation of the material. This article summarizes example results of both numerical and experimental forming of products made of hard-to-deform material.

Sheet Metal Blank Development of a Deep Drawing Fan Support Using Theoretical Rules and FEM

Deep drawing is a cost effective sheet metal forming process to produce many industrial components. However, complex geometrical drawn parts are difficult to form due to several modes and conditions of the material flow. Commonly problems associated to the forming operation are wrinkling and tearing defects, which affect the cost and quality of the parts. Actually, there are not theoretical methods developed in the literature yet, so the trial and error method are used to reduce or eliminate the deep drawing defects or inclusive is utilized in the earlier production stages, resulting in higher costs and longer production times. This paper describe a proposed solution to reduce or eliminate the wrinkles defects on the flanges of an industrial fan support that result from applying the forming process. An analysis procedure based on the development of the correct sheet metal blank considering three different blank geometries was proposed. The analysis include the analytical methods available in the literature, the simulation with a computer program based on the Finite Element Method (FEM) and experimentation. FEM model, simulation and results, these were validated by measuring the thickness profile on the flanges of a deep drawing part, before and after the procedure implementation. The results have shown that combining both the analytical and FEM methods, were possible to know the influence degree of the sheet metal blank geometry to reduce or eliminate the wrinkle defect and these can be used as an effective design tool.