Under filling and folding are two major defects, resulting in defective parts at the forging stage or failure during service life. Folding may act as a potential starting point, for crack initiation and under filled components are straight way rejected, being unusable for further processing. In the present work, an effort has been made to study the quality of forged, components by variation of billet shape, size, temperature and coefficient of friction. The output parameters observed and

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... d were normal stresses, shear stresses, effective stress, effective plastic strain, effective strain rate, die wear, load and material flow rate. It was observed that, homogeneity of deformation was higher in small parts with deep die cavity, compared to big parts. Round billet shape was found to be most suitable for reducing die wear, effective strain rate and increasing material flow rate. The flash allowance of 10% was sufficient, to fill the die cavity, completely without folding when a round billet of proper size was selected. The paper gives an insight, into the generic design of the forging process, which could help in optimizing the forging process in industry. INTRODUCTION Defects in forged components may be detected at the forging/ machining stage, or may remain hidden and result, in component failure with the passage of time. Forged components are preferred for fatigue strength and toughness, and are used in critically loaded conditions. The failure of forged component, during machining operation may be caused, by crack propagation due to defects at forging stage. In addition, the inefficient die design and selection of input parameters can result in rejection of forging components, at forging stage itself. Correct die and process design, can aid in organizing the flow of metal, which may produce parts free from the defects of under filling and folding [17] . Being critically loaded parts, any potential crack initiation site can be very hazardous. So, the production of a defect free part is crucial. Folding, a very prominent defect in forging has been dealt by many researchers [8, 10], using various case studies like connecting rod [5, 9] , and turbine blade [15] . Optimization of the forging process has also been done, using various objectives like energy efficiency [6, 7] , forging of nano structured material [9], and bi-metal forging [14], shape optimization [2], metal flow kinematics [12, 13] and variable flash thickness [16]. Various techniques have been used like equivalent static loads method [2], stochastic analysis [1], Smooth Particle Hydrodynamics [3], Monte Carlo simulation [4], Grey based Taguchi method [9], quasi potential field and response surface design [11] and slab method [12] . In the literature, the metal flow has been identified, as an important factor which results in defective parts. The quantifiable relationship between the input parameters and metal flow rate is not reported. In the present work, an effort has been made to analyses and RESULTS The results from these four sets were compared for the three parts graphically, for complete die filling and folding defect. The quantitative results were observed for effective stress, effective plastic strain, effective strain rate, die wear, load and material flow rate. The effective stress and strain were used, for comparison of deformation with different billet sizes and shapes. The effective strain rate and material flow rate, was used to compare the homogeneity of deformation, and hence the metal flow. The 3 parts were analyzed, for the effect of change of billet shape/ size and other parameters on various responses. The details are given below.