The so-called induction heating means putting the heated workpiece on intermediate frequency or high frequency AC current sensor circle. So in the workpiece, due to the induction, the induced current has same frequency with the induction coil current.
The induced current distribution is uneven on the workpiece within the vertical to the direction of power section. The current density of central part is almost zero, while the surface current density is great. That is called the skin effect. Higher the current frequency is, thinner the surface layer will be. Usually any kind of metal has a certain resistance. So with the functions of current concentrated at the surface, it will produce large amounts of joule heat and the surface will be heated rapidly.
The sintering temperature of the spark sintering indirectly reflects the heating temperature of the manganese powder from the mold, the temperature than the metal powder of diamond sintered products at much lower temperatures, so the spark sintering of sintered diamond products more appropriate. The spark sintering heating speed for the following reasons: First, sintering and spark a special mechanism to discharge the heat coupled with the joint role of the Joule heat; spark sintering of power loss, high energy utilization. Spark sintering heating rate without soaking time, so the higher the change of temperature measurement methods and measurement components to make the measured temperature is a true reflection of the real-time temperature of the sintered powder, requiring temperature measurement methods and measurement components higher, for the measured temperature to truly reflect the real-time temperature of the sintered powder, require Thermometer has high sensitivity. Sometimes the temperature measurement devices in a very short time and the temperature of the metal powder, because the insulation still 4min soaking time after the sintering temperature is reached, reflecting the temperature is essentially the true temperature of the sintered powder.
Spark sintering temperature results as far as possible to actually reach the temperature of the sintering process should do the test temperature and temperature parts, especially the very short sintering time occasions, such as the entire sintering process in seconds calculation, the temperature the more important. The flow resistance of the metal powder is very loose than small, so that the fluidity of the powder, loose powder is too large, can not be pretended. Early in the production of magnetic materials and Powder Metallurgy products production which had been used granulation, because the production of large, into one hundred tons, 10 tons of powder granulation sintering suppress the production of diamond tools in the process of granulation, can separate metal powder granulation, can with granulating diamond and metal powder diamond nuclei, coated metal powder, granulation of the latter can be reduced due to the differences in the proportion caused by mixing inequality and improve the performance of the tool.
Foe the application of ultra-fine metal powder, granulation is a technical way. If the granulation process is not properly, it will reduce performance of the tools. In general, after the granulation, it should be broken by cold pressing. Then the processes are sintering or hot pressing. If sintering or hot pressing is taken immediately after granulation, the effect is easy to imagine. It is not powder metallurgy after the granulation. So the diffusion is difficult to achieve and it has high porosity. To prevent this phenomenon, people must first put on broken nibs. It requires enough mold strength. The graphite mold may not become suitable. Although the switch to steel mold or carbide mold will increase costs, but it can get compensation from the better tool performance.Source:http://www.mhcmp.com
The application of tungsten in various industries
Steel Industry Most of tungsten applied in the production of special steels. The widely used high-speed steel was containing 9-24% of tungsten, 3.8-4.6% of chromium, 1-5% of vanadium, 4-7% of cobalt, 0.7-1.5% of carbon.
Magic effects of coconut oil
According to records, coconut oil can be regarded as the nobility of skin care plant extracts. It was rich in exotic tension of tropical plants, which can enhance the contractile force of the pores, perfectly beautify and nourish the skin.
The development trends of aloe vera extract in the international market
Aloe is a kind of perennial Liliaceae succulent herbaceous plant, originated inAfrica, belonging to tropical plant. The cultivation of aloe can be both in the open field and greenhouse.
