Friction analysis in cold forging

Cora, Ömer Necati
Friction is one of the important parameters in metal forming processes since it affects metal flow in the die, forming load, strain distribution, tool and die life, surface quality of the product etc. The range of coefficient of friction in different metal forming applications is not well known and the factors affecting variation are ambiguous. Commercially available FEA packages input the coefficient of friction as constant among the whole process which is not a realistic approach. In this study, utility of user-subroutines is integrated into MSC SuperForm v.2004 and MSC Marc v.2003 FEA packages, to apply a variable coefficient of friction depending on the contact interface conditions. Instead of using comparatively simple friction models such as Coulomb, Shear (constant) models, friction models proposed by Wanheim-Bay and Levanov were used to simulate some cold forging operations. The FEA results are compared with the experimental results available in literature for cylinder upsetting. Results show that, large variation on the coefficient of friction is possible depending on the friction model used, the part geometry and the ratio of contact normal pressure to equivalent yield stress. For the ratio of contact normal pressure to equivalent yield stress values above 4, coefficient of friction values are approximately same for both friction models.


Analysis of warm forging process
Aktakka, Gülgün; Darendeliler, Haluk; Department of Mechanical Engineering (2006)
Forging is a metal forming process commonly used in industry. Forging process is strongly affected by the process temperature. In hot forging process, a wide range of materials can be used and even complex geometries can be formed. However in cold forging, only low carbon steels as ferrous material with simple geometries can be forged and high capacity forging machinery is required. Warm forging compromise the advantages and disadvantages of hot and cold forging processes. In warm forging process, a product...
Die stress and friction behaviour analysis in bolt farming
Aygen, Mert; Kılıç, S. Engin; Department of Mechanical Engineering (2006)
In cold forming operations, tool geometry has a direct influence on the product quality, forming force, load acting on dies and tool life. Finite element method provides a means to analyse these parameters to predict forming defects and die failures. In this study, shrink fitting the components of a bolt forming die is modelled and the finite element results are compared with the analytical solutions and experiments. In order to perform die stress analyses, deformable die models are implemented in the forgi...
Elastic-plastic finite element analysis of semi-hot forging dies
Halisçelik, Murat; Darendeliler, Haluk; Department of Mechanical Engineering (2009)
Semi-hot or warm forging is an economical alternative to the conventional forging processes by combining advantages of hot and cold forging processes. In this study, a new forging process sequence and design of the preform die for a part which has been produced by hot forging are proposed to be produced by semi-hot forging. Thermo-mechanical finite element analyses are performed over the stages of forging process. The billet and the dies are modeled as elastic-plastic bodies. Effects of preform die geometry...
Experimental and numerical analysis of compression on a forging press
Biçer, Gökhan; Gökler, Mustafa İlhan; Department of Mechanical Engineering (2010)
Forging is a metal forming process which involves non-linear deformations. Finite element and finite volume software programs are commonly used to simulate the process. In these simulations, material properties are required. However, stress-strain relations of the materials at some elevated temperatures are not available in the material libraries of the related software programs. In this study, the stress-strain curves have been obtained by applying the Cook and Larke Simple Compression Test to AISI 1045 st...
Fatigue life calculation by rainflow cycle counting method
Arıduru, Seçil; Çalışkan, Mehmet; Department of Mechanical Engineering (2004)
In this thesis, fatigue life of a cantilever aluminum plate with a side notch under certain loading conditions is analyzed. Results of experimental stress analysis of the cantilever aluminum plate by using a uniaxial strain gage are presented. The strain gage is glued on a critical point at the specimen where stress concentration exists. Strain measurement is performed on the base-excited cantilever beam under random vibration test in order to examine the life profile simulation. The fatigue analysis of the...
Citation Formats
Ö. N. Cora, “Friction analysis in cold forging,” M.S. - Master of Science, Middle East Technical University, 2004.