Bar, Rod and Wire Drawing May26

Bar, Rod and Wire Drawing...

Bar, Rod and Wire Drawing  Drawing is a metal working process that forms steel work piece by reducing its cross section. This is accomplished by forcing the work piece through a die of smaller cross sectional area than the work piece. In the process of drawing the work piece is pulled through the die by means of a tensile force applied at the exit end of the die. When steel work piece is drawn, it is drawn at room temperature.  At that point, it is being cold worked or cold forged. Due to the cold working during drawing, geometric and mechanical characteristics of the steel material gets changed, transverse dimensions get reduced (e.g. diameter) and length get increased with no change in volume (waste free processing). As a result of plastic deformation in the drawing die, steel material gets also strengthened which means an increase in strength properties and decrease in plastic properties.  Deformation in drawing is influenced by a number of factors, out of which chemistry, strength of material, temperature, approach angle, lubrication, drawing speed, co efficient of friction, die life and wear, and reduction of area are the most significant. Wire drawing is primarily the same as bar drawing except that it involves smaller diameter material that can be coiled. It is generally performed as a continuous operation on the draw bench. The process of wire drawing has changed very little over the years.  It uses a combination of a die and/or a series of dies to draw wire to a selected gauge. The principle of the process is shown in Fig 1.  Fig 1 Drawing process principle  The drawing process has the following objectives Manufacturing drawn products in the form of bars or wires to a very specific and precise cross...

Main Features of a Modern Bar and Light Section Mill Feb01

Main Features of a Modern Bar and Light Section Mill...

Main Features of a Modern Bar and Light Section Mill The objective of a bar and light section mill is to reheat and roll steel billets into bars and light sections. The production of bar and light sections in these mills is subject to constant change. There is growing demands on the quality of these products as well as on the flexibility and cost effectiveness of these mills. This has necessitated the development of new and innovative technologies and processes. Modern bar and light section mills are high speed mills capable of rolling bars and light sections of special bar quality grades and engineering steels at high production rates, while keeping investments and operating costs at the reasonable levels. Modern bar and light section mills are expected to meet the following requirements. High mill availability coupled with high productivity and high yields. Meeting the need of low maintenance. Meeting the need of lower energy consumption. Close dimensional tolerances. Negative tolerances (In sectional weight). No variation in dimensions throughout the length. Uniform physical properties. For achieving these demanding requirements, many important features are incorporated in the modern bar and light section mills. Some of these are described below. Reheating furnace – Modern bar and light section mills are equipped with energy efficient walking beam furnaces which are normally computerized controlled. These reheating furnaces uniformly heat the billets to the target temperatures at the required production rates and without skid marks and without cold spots. These furnaces are capable of receiving cold or hot billets as the charge material in the furnace. The modern reheating furnaces have the features of (i) superior heated billet quality, (ii) better heating efficiency, (iii) very low fuel consumption, (iv) minimum scale loss, contributing to achieving high material yield, (v) low...