Induction heat treatment really holds up half of the heat treatment (1)

induction heat treatment has many advantages, such as high heating speed, energy saving, non-oxidation and decarbonization, non-pollution of the environment and high production efficiency. These advantages are widely recognized by heat treatment workers, so it has developed rapidly in recent decades.Of course, this actual demand, but also greatly promote the development of domestic induction heat treatment equipment and technology.Take "China FAW" in Changchun as an example, the company has nearly more than 100 induction heat treatment equipment, of which 50 have been newly added or updated in the past ten years, almost all of which are thyristor intermediate frequency equipment and IGBT super audio equipment.At present, the weight of induction heat treatment parts in the medium trucks of faW reaches 291.3kg, accounting for 52% of all heat treatment parts. Induction heat treatment truly lifts half of the heat treatment.

(2)Early induction heat treatment equipment in China

Vacuum tube high frequency power supply

Vacuum tube high frequency power supply was invented around 1930.Its main advantages are simple tuning, easy to use, despite the high frequency (later developed super audio), the application range is still wide (in the case of no attention to heating efficiency).Its main disadvantage is low electrical efficiency, about 50%;High working voltage, poor safety;Small power of single machine, etc. [2].

SCR type intermediate frequency power supply

Thyristor (SCR) intermediate frequency power supply also known as thyristor if power supply, this power supply in the world around 1970 developed successfully, and began to be used in large quantities.Our country developed successfully in about 80 time and begin to try out.By the early 1990s, it was fully mature and some of its technical indicators had reached the international advanced level.The frequency of thyristor intermediate frequency power supply used for induction quenching is generally 2.5~8kHz.Compared with machine if, it has many advantages: small size, light weight;No mechanical movement, low noise;Easy to start and stop, the frequency can be adjusted according to the needs of the parts, and automatically track in the operation, keep the operation under the highest power factor;Easy to install, no special foundation required;The single machine power of quenching equipment can reach 1000kW;The electrical efficiency can reach 90%[2].

Transistor superaudio and HIGH-FREQUENCY power supply

Transistor super audio and high frequency power supply generally refers to :(1) IGBT super audio power supply, MOSFET high frequency power supply and SIT high frequency power supply.Transistorized super audio and high frequency power sources were developed in the late 1970s.Our country developed successfully in the 1990s.At present, the domestic IGBT power supply has been very mature, and some indexes of IGBT power supply produced by our company have reached the international advanced level: the power of frequency 8~50kHz can reach 500kW, and the power of frequency 50~100kHz can reach 200kW.Domestic MOSFET can achieve 200kHz and 100kW.SIT high-frequency power supply has been produced dozens of domestic, but due to the lack of spare parts, has been scrapped.SIT power is difficult to overcome due to the small power of a single tube shortcomings, foreign companies have stopped research and development and production.

At present, the current situation and development of induction heat treatment power supply equipment in China is the key equipment of induction heat treatment.At present, the heat treatment industry in China in addition to the most ancient spark-gap type hf power supply is not in use, other types of power supply are in use, in which machine type if generator and vacuum tube type HF power supply although backward, in some areas or factories, is still the main production equipment.The advantages and disadvantages of various power sources are introduced as follows:

Mechanical if generator Mechanical if generator was developed successfully around 1920. In that year, Clark Company in Ohio first used it for the quenching of crankshaft journal, which was the earliest industrial intermediate frequency power supply.Its biggest advantage is its durability, in addition to years of work to replace the bearing, almost no maintenance.Its disadvantage is that the frequency is fixed and the range of use is limited.Large floor space;Noise;High water consumption;The electrical efficiency is low, about 70~75%.