Friction and Lubrication

Modeling of cold pilgering of stainless-steel tubes

“…Friction is a complicated phenomenon due to complex micro-scale formations on the interfaces, especially when the lubrication is involved [2,41,42]. There are several factors influencing the friction such as the contact topology, material properties, relative sliding velocity and the presence of lubrication.…”

“…There are several factors influencing the friction such as the contact topology, material properties, relative sliding velocity and the presence of lubrication. The Stribeck curve [43] divided the contact conditions in four regions [42,44]. They are dry, boundary, mixed and hydrodynamic conditions and based on the asperity height and oil film thickness.…”

Design of a Tribo-Simulator for Investigation of the Tribological Behavior of Stainless-Steel Sheets Under Different Contact Conditions

“…Trzepiecinski 2 noted that the mechanical properties of the metallic sheet are an important factor, and inadequate consideration of this factor in the design of SMF manufacturing processes causes buckling, excessive thinning, tearing, and wrinkling of the components. However, an extensive amount of research has listed several other factors that affect the final shape of the components, such as the geometry of the tool (e.g., punch-to-die clearance and die and punch radii), technological parameters (e.g., temperature and forming speed), properties of the tool material (e.g., hardness and chemical composition), and friction conditions or contact (e.g., dry or lubricated contact, lubricant type, contact pressure, initial surface topography, and geometry and kinematics of tribocontact) [1][2][3][4][5][6][7][8][9] .…”

Tribological Behaviour of Lubricants in Hot Stamping of AA6016

“…In these applications, friction is known to be a function of many factors, including the type of lubricant, tool geometry and the surface condition of the material, but is not clearly understood [6]. Friction at the interface between the material and the tool during a forming operation is influenced not only by physical parameters, such as the tool geometry, but also by process parameters like sliding velocity, temperature and contact pressure [7]. The assumption of a constant friction coefficient is, therefore, not always representative of the actual conditions within the press tool during a forming operation, and improvements to the simulation tools could be achieved by studying the effects of changes in the surface condition, and hence friction, during a forming operation [8].…”