The first, who suggested the use of hdtv for the heating of metals, was Vologdin vp in 1923. and only in 1935 began to apply a high frequency heating for hardening metals. Today hardening is used in virtually all sectors . hdtv surface hardening are used to the fact that to increase the hardness of the hardened layer and simultaneously increase the viscosity in the center of the details. This is possible because at high frequency hardening the top layer is heated up to do Zalki temperature and immediately cooled, and the core components retain their properties.
Due to the fact that the core is a viscous, the item becomes less fragile. hdtv allows you to quench hardening of the concrete details which is necessary to give the desired properties, not the whole piece as a whole. hdtv hardening. Advantages: 1) high frequency hardening economical than conventional hardening, because when heated by high frequency quenching only a necessary element of detail, plus reduces the time 2) the high frequency quenching reduces marriage to warping and cracking, and 3) high frequency hardening is not conducive to burning carbon and scaling, and 4) depending on the need, you can change the depth of the hardened layer; 5) application of high frequency hardening, the mechanical properties of steel is higher than a conventional quenching. 6) When using high frequency hardening is practically no strain, and 7) High automation and mechanization of the process. hdtv hardening. Disadvantages: 1) enough difficult to handle the intricate details of 2) is not beneficial to use with no high-volume production of high frequency surface hardening.
Its species: – hd hardening stationary (detail and the heater did not change my position. Used to hardening of flat parts (surfaces) are not large) – hd hardening continuous sequence (in this case, the item moves under the heater, any part remains in place, and the heater going in the direction of the details. Is also used for flat parts (surfaces), as well as cylindrical parts (surface). HD-hardening tangential continuous sequences (item scrolls once. It is used only for cylindrical parts are not very large.) Another disadvantage of high frequency quenching, it is something that is very important, which form a part, and in some cases, high frequency quenching is not suitable for machining because of their shape. In this case, use grouting with heat treatment to increase strength and durability, but the cost of this method will be in 2 – 3 times more expensive than the cost of hardening of hdtv. hdtv is used for hardening of medium steels (0,4-0,45% C) or for strengthening the internal layer of alloy components