Views: 21 Author: Site Editor Publish Time: 2018-12-19 Origin: Site
The morphological distribution of the tungsten-copper powder sintered material is uniformly distributed on the copper substrate with tungsten as a skeleton. Due to the high melting point and high hardness of tungsten W, the ultimate tensile strength of tungsten at 1000 ° C is still 50kgf / mm2, which is higher than the strength of low carbon steel at room temperature, which makes the tungsten copper material in the melting point of copper. Below the temperature (about 1000 ° C), it still has extremely high abrasion resistance and hot hardness. The tungsten skeleton is bonded to the base of copper, and constitutes a good conductor and heat dissipation path of the sintered material, so that the tungsten skeleton does not cause local overheating during use.
The room temperature strength of commonly used metals is mainly determined by two basic factors, namely metal atom binding force and resistance to dislocation motion. In the case of tungsten-copper materials as resistance welding electrodes, methods for increasing the resistance to dislocation motion are often used to increase the strength, including cold work hardening and removal strengthening. However, the strengthening effect obtained by these methods is significantly reduced as the temperature of the tungsten-copper alloy increases, and eventually disappears. For example, the cold-hardened copper electrode can reach HB100-110 at room temperature, but when the temperature rises to 200-250 °C, the cold work hardening effect will disappear. In addition, most of the copper alloys which are precipitated and strengthened by the precipitation phase, when the temperature reaches 500-650 ° C, the strength gradually decreases due to the re-integration of the precipitate phase into the matrix. In contrast, copper-tungsten powder sintered materials do not undergo phase transformation, recrystallization or recrystallization at high temperatures. Some research data on tungsten-copper materials show that the hardness and electrical conductivity of tungsten-copper W-30Cu is higher than that of beryllium copper, and the softening temperature is more than twice that of beryllium copper. Therefore, tungsten-copper materials are used as electrodes for flash butt welding or arc welding, especially in the case of continuous operation at high temperatures, where the requirements for electrical conductivity and wear resistance are high, and the tungsten-copper electrode material is more prominent. Superiority.