Presentation on theme: "Forging Workshop Technology ME-121 (1-2 Cr. Hr.) Mansoor Ghazi, Department of Mechanical Engineering College of E&ME, NUST Pakistan."— Presentation transcript:
Forging Workshop Technology ME-121 (1-2 Cr. Hr.) Mansoor Ghazi, Department of Mechanical Engineering College of E&ME, NUST Pakistan
What You Will Learn What is forging Various forging techniques Equipment for forging A bit of math behind forging (analysis) Some simple examples
What is Forging A metal forming technique used to shape metals by application of local compressive forces. Compressive forces can be generated in a metal either through impact (with hammers) or by gradually pressing (with presses). Forging is typically used to establish a basic/initial shape of a part.
Forging and Temperature Metal can be shaped at both low and high temperatures by appropriate application of force/pressure. Based upon temperature forging is classified as: – Hot or Warm Working: Requires less force/pressure. Increases ductility but reduces strength – Cold Working: Increases strength but requires greater forces/pressure
Dies and Types of Forging Dies are used to constraint the workpiece between two or more surfaces while force is being applied to it. Based on the type of die being used, forging can be classified as: – Open Die Forging – Impression Die Forging – Flashless Forging
Open Die Forging It involves compression of a workpiece between two flat dies and is similar to compression testing. At times the dies are not purely flat. Resulting deformation reduces the height but increases the cross section of a workpiece. Such a deformation process is also known as upsetting or upset forging. If no friction occurs between the die and workpiece under compression, a uniform deformation occurs in which radial flow is uniform throughout the workpiece height.
Open Die Forging with Friction In the absence of a lubricant, friction between the workpiece and die surfaces pops up. Due to friction between the workpiece and die surfaces, metal flow becomes non-uniform. Consider the example of water flowing in a river; water flows faster in the center and slower near the river bank. In hot forging, friction effects are even more pronounced.
Advantages – Higher production rates – Less material wastage – Higher Strength and Strength to Weight Ratios – Favorable grain orientation in the metal crystalline structure Disadvantages – Not capable of close tolerances – Machining is often required to achieve the desired level of final accuracy and features