Cold drawing machine is a process of reducing the size and shaping metal bars, rods, and coils. The cold drawn product offers many benefits over hot-rolled products such as increased mechanical properties, improved machinability, and precise dimensional tolerances. During the cold drawing process, steel is pulled through carbide dies that have been contoured to the final shape of the part being produced. Several passes through the dies are required to reduce the overall size of the material.
To begin the drawing process, the raw material is submerged in a lubricant. This is done to help the steel bar pass through the die more easily. The lubricant is also used to remove any abrasive scale or roughness that may be present on the bar or coil. Next, the lead ends of the steel are processed to make them smaller than the rest of the stock. The smaller lead end allows the steel to travel through the die more easily and prevents the stock from jamming on the die during the drawing process.
Then, the lubricated steel is passed through a set of drawn dies to further reduce its diameter and shape the profile of the finished product. Each drawn die reduces the cross-section of the original bar or coil by a different amount. The final drawn product is much thinner and narrower than the original product, while at the same time maintaining a consistent tensile strength and yield strength.
While the energy-power mathematical models developed by HOREN have been applied to a wide range of alloys, the specific equations for changing the tensile and yield strength of the NP2 nickel wire from cold work are individual for each alloy. In addition, these formulas depend on technological parameters such as the drawing speed and the design of the drawn route.
During the design of a drawing route, the energy-power parameters are influenced by a variety of factors such as the number and length of drawn dies, the size of the die, and the draw cycle. These parameters are also influenced by the geometry of the dies and the friction coefficient at the metal-wire contact. For these reasons, it is important to use an accurate computer program when designing drawing routes for industrial applications. For example, a new computer simulation has been developed that uses a one-dimensional explicit finite difference method to predict the plastic deformation of the drawn alloy in the dies. The results indicate that the model produces more accurate prediction of stress ratios and drawing forces than a bulk model using redundant work formulations. The results also suggest that it is possible to improve the quality of the drawn product by adjusting the semi-die angle away from the traditional eight degrees. These results should provide useful guidance to engineers and managers in the selection of a suitable drawing route for their specific application. This will result in higher quality products with lower energy costs. This is especially true in high-volume production runs, where the energy cost of each kW of power consumed can be very significant.