In the case of stretching, try to choose a large section shrinkage rate γ, which can reduce the radial positive pressure Kmr and reduce the internal loss As of the shearing force; after the section shrinkage rate γ and the friction coefficient μ must be determined, the drawing die has the smallest The half-angle α of the climacteric cone must be, which is an ideal cone half-angle α'that minimizes the drawing force. Working under this cone half angle α’, the frictional force Zr and the external loss work Ar, the shear force and the internal loss work As will be
The smallest, the service life of the cemented carbide die will be the best; in the range of 6°~16°, with the addition of α, the radial extrusion force on the wire drawing die will be smaller.
2) The influence of the length of the sizing belt on the life of the drawing die. If the wire drawing die sizing belt is too short, long-term wear will simply damage the sizing belt or increase its size; if it is too long, additional work is required, which reduces the power of the engine and increases the temperature of the wire drawing die. , Simple failure.
3) In the process of drawing, the quality of the smoothing agent and the supply of smoothing agent affect the service life of the drawing die. The smoothing agent has smoothing, cooling, cleaning and anti-rust effects in the wire drawing process. Regarding the cleanliness of the wire drawing smoothing agent, filtering equipment using wire drawing smoothing agent is now available, and the filtering method and filtering gap are selected according to the particle size to be filtered. At the same time, the proper concentration of the drawing smoothing fluid is also one of the main factors affecting the service life of the mold. The best smoothing fluid application parameters are obtained based on experiments. It is necessary to consider the die life and drawing power. The relatively economical cost while ensuring the outstanding smoothing effect is the basis for determining the concentration of the drawing smoothing fluid.
4) If there is an oxide layer, sand or other impurities on the surface of the metal blank, it will adversely affect the service life of the wire drawing die. Because the oxide layer on the surface of the metal is hard and brittle, when the metal blank passes through the die hole, it will form a wire drawing die hole like an abrasive, which will quickly wear and scratch the surface of the conductor. Therefore, before stretching, pickling, peeling and other methods should be used to remove the oxide layer when necessary. The small line should pay special attention to the storage environment of the blanks (temperature and humidity, gas composition, etc.) to prevent it from oxidizing. When the blanks are piled up, pay attention to the neatness of the stacking place to prevent contact with sand and other impurities. In the process of fine wire drawing, the burr of the blank itself also affects the life of the mold.
5) Suitable wire drawing dies should be selected for drawing wires of different materials, and the hardness of the wire and drawing dies should not be too different to prevent unnecessary spoilage.
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