Drawing die structure

With the deepening of reform and opening up, wire drawing dies and corresponding die hole inspection instruments made by industrially developed countries have been introduced in China. Through the analysis of the hole pattern of foreign wire drawing dies, we can understand the design ideas of modern wire drawing dies and provide a reference for improving the design level of Chinese wire drawing dies.

According to the nature of work, the structure of the wire drawing die core can be divided into five sections: "entrance zone, lubrication zone, working zone, sizing zone, and exit zone". The inner diameter profile of the drawing die is very important, it determines the tension required to compress the wire and affects the residual stress in the wire after drawing. The functions of each area of the mold core are: the entrance area, which facilitates threading and prevents the wire from scratching the drawing die from the entrance direction; the lubrication area, through which the steel wire is easy to bring lubricant; the working area is the main part of the die hole, and the deformation of the wire The process is carried out here, that is, the original cross-section is reduced to the required cross-sectional size. When drawing conical metal, the space occupied by the volume of the metal in the working area is a truncated cone, which is called the deformation zone. The cone half angle α (also known as the die hole half angle) in the working area is mainly used to determine the drawing force; the sizing area is used to obtain the exact size of the drawn steel wire; the exit area is used to prevent the unsteady exit of the steel wire And scratch the surface of the wire.

With the increase of the wire drawing speed, the service life of the wire drawing die has become a prominent problem. Americans T Maxwall and E G Kennth proposed a new wire drawing die hole pattern theory suitable for high-speed wire drawing, that is, the "straight line" theory. The wire drawing die made according to this theory has the following characteristics:

① The entrance area and lubrication area are combined into one, which has a tendency to reduce the lubrication angle, so that the lubricant is subjected to a certain pressure before entering the working area, thereby achieving a better lubrication effect.

②The entrance area and working area are lengthened to establish a better lubrication pressure, and the angles are optimized according to the drawing material and the compression rate of each pass.

③The sizing area must be straight and reasonable in length.

④The vertical line of each part must be straight.