1. The process of the drawing process
The metal drawing process is carried out on a sheet metal deep drawing machine. In metal drawing or deep drawing, a metal sheet or blank is drawn through a drawing punch. The punch enters the die to shape the sheet, which is a metal drawing (or deep drawing). Usually cylindrical or box-shaped parts are formed by drawing or deep drawings, such as beverage cans, barrel-shaped parts, butterfly-shaped parts, and other containers and mobile phone casings of various shapes and sizes. Taking drawing metal steel pipes as an example, the process flow is: sharpening → degreasing and rust removal → water washing → phosphating treatment → water washing → immersion in lubricating fluid → drying → drawing → straightening → cutting → oiling → packaging, etc.
Second, the classification of the drawing process
1. According to the classification of drawing lubricating materials, can be divided into dry drawing and oil drawing. Dry drawing uses drawing powder as a lubricant, which is mainly used for drawing wires that do not require a high appearance, and the drawing speed is low. Oil drawing uses special drawing oil as a lubricant, which is mainly used for drawing bright wires with high surface quality requirements. It is characterized by good lubricity and cooling effect and fast drawing speed.
2. According to the drawing speed of the equipment, it can be divided into medium and low-speed drawing and high-speed drawing. With the improvement of the technological level, the rate of medium and low-speed drawing is also increasing.
3. According to the drawing materials, there are low carbon steel, medium carbon steel, high carbon steel, stainless steel, copper, aluminum, and other materials.
4. According to the section of the workpiece, it can be divided into solid section workpiece drawing and hollow section drawing. The solid section blank is drawn into various specifications and shapes of wire, among which the process of drawing round section wire is the most simple. Pipes of various shapes are drawn from hollow section blanks. When the pipe wall is generally stretched, the core rod and the arm blank pass through the mold to achieve diameter reduction and wall reduction.
3. The problem with the drawing process
1. The common problems of large and medium diameter wire rods are: ①The wire rod is not bright and has pull marks; ②The strain is severe and the mold is severely worn; rust;
2. The common problems of small diameter wire rods are: ① Frequent wire breakage and serious shrinkage; ② The wire rod is not bright and has scratches; ③ The wire rod is oxidized and discolored;
3. The common problems of micro-diameter wires are: ① Frequent wire breakage and serious wire shrinkage; ② The workpiece is seriously adsorbed and difficult to clean;
Fourth, the selection of drawing oil
1. According to the different raw materials in wire drawing, the formula of suitable drawing oil will be different. For example, the drawing of stainless steel wire requires the use of special drawing oil for stainless steel. Therefore, when purchasing, you need to choose the appropriate type of oil according to the actual material;
2. Different drawing processes have different performance requirements for drawing oil, so it is necessary to select drawing oil with suitable performance according to the actual process (such as drawing speed, reduction ratio, the surface finish of the workpiece, etc.);
3. The formulations of different types of drawing oil are not the same, and the performance in the actual process is different, so the applicable objects are also different.
