Forging Manufacturing Process PDF

SIT Internal Forging Open-Die Forging Forging is a manufacturing process involving the shaping of metal using localized Closed-Die Forging compressive forces. The blows are delivered with a hammer (often a power hammer) or a die. Produces discrete parts...

SIT Internal Forging Open-Die Forging Forging is a manufacturing process involving the shaping of metal using localized Closed-Die Forging compressive forces. The blows are delivered with a hammer (often a power hammer) or a die. Produces discrete parts (rolling: continuous) 1  SIT Internal Forging 2  SIT Internal Forging – Effect on Structure Grain flow in component made by three different processes. Forged parts have good strength and thoughness – metal flow in die and material grain structure is controlled Forged parts are very reliable in highly-stressed and critical applications Grain flow random as it is Grain flow follows that of Grain flow oriented in the formed through starting material direction of the pressure solidification of molten imposed on part metal 3  SIT Internal General Characteristics of Forging Processes  SIT Internal Forging – Open & Closed-Die Open-Die Forging Open-die forging is the simplest forging operation Part sizes may range from very small (such as pins, nails, and bolts) to very large (long shafts for ship propellers). Metal workpiece (blank), placed between two flat dies, and reduced in height by compressing it. Any reduction in height increases the diameter of Ideal versus Real the forged part. Closed-Die Forging Closed-Die: workpiece takes the shape of the die cavity while being forged between two shaped dies Usually at elevated temperatures, in order to lower the forging forces and develop enhanced ductility of the workpiece. Some of the material flows outward and forms a flash. The flash has an important role in impression-die forging: ensures that material fills the die cavity completely.  SIT Internal Forging – Closed-Die Forging True Closed-Die Forging (or Flashless Forging) (a) Closed-Die Forging with flash (b) Precision or Flashless forging True Closed-Die forging: flash does not form Workpiece completely fills the die cavity The accurate control of the blank volume and proper die design are essential to producing a forging with the required dimensional tolerances. Undersized blanks prevent the complete filling of the die cavity. Oversized blanks generate excessive pressures and may cause dies to fail prematurely or the machine to jam.  SIT Internal Forging – Materials Forgeability of Metals (Blanks) Requirements for die materials: (in Decreasing Order) Strength and toughness, especially at elevated temperatures Hardenability and ability to harden uniformly Resistance to mechanical and thermal shock Wear resistance, particularly resistance to abrasive wear, because of the presence of scale in hot forging Dies are made from die blocks, which Forgeability is generally defined as the capability of a themselves are forged from castings, material to undergo deformation in forging without cracking. and then machined and finished to the desired shape and surface finish.