Cold Drawn Flat Bar

Drawing is a metal working process in which metal is drawn through a die to reduce its diameter and increase its length, it stretches thinner, into a desired shape and thickness. It uses tensile forces to stretch metal.

Drawing is usually done at room temperature, thus classified as a cold working process.It also alters the mechanical properties of the metal.

Cold drawn cross-sections are more precise and have a better surface finish than hot extruded parts.
The cold drawing process for steel bars and wire-

• Coating: The surface of the bar or coil is coated with a drawing lubricant to produce cold drawing.
• Pointing: The end of the workpiece is reduced or pointed by extruding so that it can pass freely through the die. The pointing end is then placed in grips and the rest of the workpiece is pulled through the die.
• Cold Drawing: The process in which the pointed end of the bar or coil is passed through the die where it enters a gripping device of the drawing machine. The drawing machine draws the remaining unreduced section of the bar through the die. The die reduces the cross sectional area of the original bar increases the length of the original product and shapes the profile of the product.
• Finished Product: The final product being drawn is at room temperature i.e cold drawn which exhibits a bright and polished finish, improved machining characteristics, increased mechanical properties, precise and uniform dimensional tolerances.
• Multi-Pass Drawing: In order to produce the desired shape and tolerances, the cold drawing of complex shapes may require that each bar/coil be drawn several times. This process is called multi-pass drawing and involves drawing through smaller and smaller die openings. The material is generally annealed between each pass while drawing to remove cold work and to increase ductility.
• Annealing: It is a heat treatment process generally used to soften the material being drawn, to remove internal stresses in the product or modify the mechanical properties, its microstructure, and the machining characteristics of the steel.Annealing may be used before, during i.e between passes or after the cold drawing operation, depending on the desired characteristics of the finished product & material requirements.