Wire and Rod Drawing Process for Steel Nov13

Wire and Rod Drawing Process for Steel...

Wire and Rod Drawing Process for Steel Drawing of wire from steel rod is a metal working process used for the reduction of the cross-section of the rod. Similarly rods are drawn from steel rounds of larger diameters. During drawing the volume remains the same and hence there is increased in the length of the drawn wire or rod. It is carried out by pulling the wire/rod through a single or a series of the drawing dies. In the case of series of drawing dies, the subsequent drawing die is to have smaller bore diameter than the previous drawing die. Drawing is usually performed in round sections at room temperature, thus it is classified as a cold working process. However, it can be performed at higher temperatures for large wires to reduce forces. Drawing process normally is most frequently used to produce round cross sections, but squares and other shapes can also be drawn. Wire/rod drawing is an important industrial process, providing commercial products. Rod and wire products cover a very wide range of applications which include shafts for power transmission, machine and structural components, blanks for bolts and rivets, electrical wiring, cables, wire stock for fences, rod stock to produce nails, screws, rivets, springs and many others. Drawing of rods from steel rounds is used to produce rods for machining, forging, and other processes etc. Advantages of drawing in the above applications include (i) close dimensional control, (ii) good surface finish, (iii) improved mechanical properties such as strength and hardness, and (iv) adaptability to economical batch or mass production. In the process of drawing, the cross section of a long rod or wire is reduced or changed by pulling (hence the term drawing) it through a die called a draw die. Pulling of rod...

Hot Rolled Steel Bars and Shapes...

Hot Rolled Steel Bars and Shapes Hot rolled steel bars and hot rolled steel shapes are produced from rolled in hot rolling mills or continuous cast blooms or billets and comprise a variety of sizes and cross sections. Bars and shapes are most often produced in straight lengths, but bars in some cross sections in smaller sizes are also produced in coils. The term ‘bar’ includes (i) rounds, squares, hexagons, and similar cross sections 10 mm and greater across, (ii) flats greater than 5 mm in thickness and 150 mm and less in width or greater than 6 mm in thickness and 200 mm and less in width, (iii) small angles, channels, tees, and other standard shapes less than equal to 75 mm across, and (iv) concrete reinforcement bars. The term ‘shape’ includes structural shapes and special shapes. Structural shapes are flanged, are 80 mm or greater in at least one cross-sectional dimension, and are used in structures such as bridges, buildings, ships, and railway wagons. Special shapes are those designed by users for specific applications.  Fig 1 shows various types of hot rolled bars and shapes. Fig1 Types of steel bars and shapes Dimensions, tolerances and surface imperfections The nominal dimensions of hot-rolled steel bars and shapes are designated in millimeters with applicable tolerances, as shown in the applicable standards. Bars or shapes can be cut to length in the rolling mill by a number of methods, such as hot or cold shearing or sawing. The method used is determined by cross section, grade, and customer requirements. Some end distortion is to be expected from most methods. When greater accuracy in length or freedom from distortion is required, bars of shapes are normally cut over-length, and then recut on one or both ends...