Initial location of the billet and the shape of die have an important effect on parameters of precision forging. Some of these effects are the contact stresses, material flow, distribution of stress, and also strain. In the present study, the die shape influences and the billet position in precision forging of two different shape groups have numerically and experimentally been investigated. Res...

ZTA powder with a composition of 85 wt% alumina/15 wt% zirconia was prepared by a gel precipitation method. Sinter forging was performed with this powder to enhance the mechanical properties of ZTA materials. The influence of processing flaws on mechanical properties of sinter forged materials and pressureless sintered materials was investigated. Sinter forging at 40 MPa effectively decreases p...

In warm and hot forging, the dies are subjected to high contact pressures and temperatures. The selection of the die material, hardness and coating is critical for increasing die life. Recent studies indicate that ceramic dies and various surface treatment techniques represent, in certain applications, cost effective techniques for improving die life. This paper reviews the state of technology ...

A majority of high-strength constructional elements of titanium alloys are manufactured by hot plastic working methods, chiefly by open die forging or die forging. Most often, β α + two-phase titanium alloys are used, which are characterized by high relative strength, good hightemperature creep resistance (up to 450°C), high fatigue strength under corrosive conditions, corrosion resistance in m...

-A method of discretizing the die boundary conditions is considered for the analysis of metal forming processes by the rigid viscoplastic finite element method. The method is natural to the finite element method and general enough to treat the boundary conditions of arbitrarily shaped dies in a unified way. Solutions of the spike forging process are obtained by using the method. The deformation...

The results from experimental research of deformation by upsetting and die forging of lead specimens wit controlled impact are presented. Laboratory setup for conducting the investigations, which uses cold rocket engine operated with compressed air, is described. The results show that when using controlled impact is achieving greater plastic deformation and consumes less impact energy than at o...

Aluminum alloys with nanocrystalline (NC) and ultrafine grain (UFG) size are of interest because of their strengths that are typically 30 pct greater than conventionally processed alloys of the same composition. In this study, UFG AA 5083 plate was prepared by quasi-isostatic (QI) forging of cryomilled powder, and the microstructure and mechanical behavior was investigated and compared with the...

In multi-operation forging processes, the process fault due to missing parts from dies is a critical concern. The objective of this paper is to develop an effective method for detecting missing parts by using automatic classification of tonnage signals during continuous production. In this paper, a new feature selection and hierarchical classification method is developed to improve the classifi...

The paper reports on an investigation into the various aspects of closed die cold forging of polygonal powder preforms, which have been compacted and sintered from atomized powder. It is found that for certain dimensional ratios of the preform the die pressure is minimum. An attempt has been made for the determination of the die pressures developed for given geometries of the disc during the cl...