The Analysis of Deformability, Structure and Properties of AZ61 Cast Magnesium Alloy in a New Hammer Forging Process for Aircraft Mounts

This article presents the analysis of the deformability, structure and properties of the AZ61 cast magnesium alloy on the example of a new forging process of aircraft mount forgings. It was assumed that their production process would be based on drop forging on a die hammer. Two geometries of preforms, differing in forging degree, were used as the billet for the forging process. It was assumed that using a cast, unformed preform positively affects the deformability of hard-deformable magnesium alloys and flow kinematics during their forging and reduces the number of operations necessary to obtain the correct product. Numerical analysis of the proposed new technology was carried out using DEFORM 3D v.11, a commercial program dedicated to analyzing metal forming processes. The simulations were performed in the conditions of spatial strain, considering the full thermomechanical analysis. The obtained results of numerical tests confirmed the possibility of forming the forgings of aviation mounts from the AZ61 cast magnesium alloy with the proposed technology. They also allowed us to obtain information about the kinematics of the material flow during forming and process parameters, such as strain intensity distribution, temperatures, Cockcroft–Latham criterion and forming energy. The proposed forging process on a die hammer was verified in industrial conditions. The manufactured forgings of aircraft mounts made of AZ61 magnesium alloy were subjected to qualitative tests in terms of their structure, conductivity and mechanical properties.

Theoretical and experimental investigations of mechanical vibrations of hot hammer forging

The characterization of mechanical vibrations in a hammer forging process is a tremendously important parameter for machine design and production engineering. The dynamic response of a forging hammer to the reaction forces is affected by material behaviour, time, spring-damper system and foundation. In this research firstly, the effect of mass ratio and coefficient of restitution on the forging efficiency were theoretical characterized. The interesting influence of anvil initial velocity on the forging efficiency is also analytically presented. The mechanical vibrations of a LASCO HO U-315 hammer were experimentally investigated. Two steel grades a S355 and a 42CrMo4 were used to forge trial parts. The velocity of the ram and acceleration of the anvil during a hot die forging process were measured using a laser velocity meter type LSV-2000-45. The influences of forging time, coefficient of restitution, energy loss and time interval (delay) between blows on the efficiency of the forging process were examined. The energy loss before die contact was determined to be approximately 10%. The investigations also showed that a variation of the time interval between blows within the usual range has no effect on the intensity of the vibrations of the anvil nor on the energy loss of the hammer. The dependence of the free damped vibrations of the anvil on machine stiffness, damper coefficient and mass of machine has been confirmed. Additionally, the loss of energy due to hammer movement as well as the free damped mechanical vibrations of the anvil were theoretically analysed in order to verify the experimental findings. Theoretical analysis showed an anvil initial velocity of approximately 0.2 m/s results in a 4% increase of forging efficiency. A good agreement between the experimental and theoretical results was observed.

Analysis of a new process of forging a 2017A aluminium alloy connecting rod

The paper presents the results of a theoretical analysis of a new process of hammer forging of a connecting rod and the technology currently used. In the industry at present connecting rods are forged from extruded rods. The new forging technology assumes the use of a billet in the form of a cast preform. For the calculations, it has been assumed that the billet material will be a Ø30 x 148 mm rod and a cast preform. Two variants of preforms have been modelled, from which products of the assumed geometry with different degree of strain are obtained. Calculations were made using the finite element method in the Deform 3D program. The input material was 2017A aluminium alloy in the form of rods and sand cast preforms. On the basis of the conducted research it was found that the use of cast preforms reduces material waste by about 80% in relation to the technology of forging from the bar, and reduces the energy consumption of the process by about 75%. Both geometrical variants of the forging preforms ensure obtaining a forging with the assumed shape and dimensions, although forging from the forging preform with a smaller degree of strain seems to be a safer variant in terms of the possibility of cracking of the material. This is supported by the lower strain and Cockcroft-Latham integral values.

ANALISA KERUSAKAN DIES HAMMER FORGING MATERIAL SKT4 UNTUK PROSES PRODUKSI UNDER BRACKET

Forging merupakan salah satu proses pengerjaan logam yang dilakukan dengan cara merbah bentuk material logam dengan memberikan gaya tekan melalui cetakan die sampai terjadi deformasi plastis pada material. Gaya tekan akan merubah bentuk serta dimensi benda kerja secara permanent mengikuti profil yang ada pada cetakan.Faktor yang melatar belakangi terjadinya kerusakan pada dies dipengaruhi oleh gaya dan tegangan yang bekerja, serta struktur dan kekerasan material dies tersebut. Dilakukan pengujian untuk memastikan penyebab kerusakan, meliputi pengujian struktur mikro,komposisi kimia, dan uji kekerasan. Hasil pengujian diperoleh bahwa kerusakan dies, disebabkan adanya material las pada dies. Selain gaya dan tegangan serta pembebanan yang berlebih. Awal kerusakan berada pada material dies yang berhubungan langsung dengan beban statis dan terdapat material las di bagian tersebut.

Investigation of the Hammer Forging Process of Large-Sized Turbine Blades of Stainless Steel

Investigations of the rheological properties and the formation of the structure of stainless steel were performed. A computer model of the process of hammer forging of the turbine blades made of stainless steel 1.3 m long in the package Deform-3D was developed , with the help of which the necessary coefficients and parameters are determined to ensure maximum convergence of the calculated and experimental process data. The obtained data were used to create a mathematical model for stamping a large-sized turbine blade made of stainless steel with a length of 2.1 m. Mathematical modeling of the processes of stamping and distorting of a large-sized blade in the software package Deform-3D has been performed. The influence of process parameters on the stress-strain state (SSS), forming, temperature field in the forging at various stages of stamping. Determined temperature and deformation modes of stamping, the need for additional heating and optimal forgings geometry by stamping.

Microstructural Characterization and Mechanical Properties of Ti-6Al-4V Alloy Subjected to Dynamic Plastic Deformation Achieved by Multipass Hammer Forging with Different Forging Temperatures

Dynamic plastic deformation (DPD) achieved by multipass hammer forging is one of the most important metal forming operations to create the excellent materials properties. By using the integrated approaches of optical microscope and scanning electron microscope, the forging temperature effects on the multipass hammer forging process and the forged properties of Ti-6Al-4V alloy were evaluated and the forging samples were controlled with a total height reduction of 50% by multipass strikes from 925°C to 1025°C. The results indicate that the forging temperature has a significant effect on morphology and the volume fraction of primary α phase, and the microstructural homogeneity is enhanced after multipass hammer forging. The alloy slip possibility and strain rates could be improved by multipass strikes, but the marginal efficiency decreases with the increased forging temperature. Besides, a forging process with an initial forging temperature a bit above β transformation and finishing the forging a little below the β transformation is suggested to balance the forging deformation resistance and forged mechanical properties.