High frequency annealing equipment widely used

High frequency quenching machine equipment can be used to quench all kinds of mechanical parts in general or in part. High frequency quenching is widely used in automotive parts industry, such as fuel injection nozzle quenching, small copper parts quenching, wire hole quenching, etc.

High frequency quenching machine equipment can also carry out stretching quenching for stainless steel rigid wares with diameter of 400, in-situ stress removal of gantry frame load-bearing beam, in-situ stress quenching, in-situ quenching of motor stamping, in-situ bluing of iron core after lamination of non-coated electrical steel, and in-situ quenching of titanium tube, etc.

After quenching the hair germs of most equipment parts and abrasives, the thermal stress and component asymmetry of casting, forging and welding parts can be eliminated. The physical properties of steel can be improved and adjusted by the manufacturer of large-scale pull-back device, and the mechanism can be prepared in advance for the next process. Quenching can be used as the final quenching and tempering treatment for parts with low specifications and less critical characteristics, as well as some general casting and welding parts.

The quenching of steel is to heat the steel to a moderate temperature, heat insulation must be time, and then slow water cooling, in order to get the heat treatment method close to the equilibrium mechanism. The purpose of quenching depends on the symmetrical composition, the improvement of physical and service properties, the removal or reduction of thermal stress, and the preparation of the final quenching and tempering mechanism for the parts.

Isothermal quenching is used in steels and some non-ferrous metals such as titanium, which is controlled by water cooling. For steel, it is slowly heated to about a little temperature of Ac3 (hypoeutectoid steel) or Ac1 (eutectoid steel and hypereutectoid steel). After a period of heat insulation and heat preservation, the steel martensites, and then moves rapidly into another furnace with very little temperature below A1. The isothermal temperature is maintained until all changes of martensite into lamellar ferrite (hypoeutectoid steel). There are also pre-eutectoid metallographic structures; there are pre-eutectoid carbides in hypereutectoid steels) that have been eventually cooled by water at an arbitrary rate (usually announced as water cooling in gases). The range of approximate temperature of isothermal maintenance is within the range of A1 to ferrite change nose temperature on the isothermal variation diagram of alloy structural steels (see low temperature martensite change diagram); the actual temperature and time are determined by the strength prescribed after quenching.

If the isothermal temperature is too low or too high, the strength after quenching will be too high; if the isothermal temperature is too high, the isothermal maintenance time must be increased. The purpose of isothermal annealing of steel is consistent with recrystallization quenching, but the actual operation of processing technology and the need for machinery and equipment are very complex, so the key is generally applied to low-temperature martensite in the ferrite transformation temperature zone equivalent to slow change of carbon steel. If the former chooses recrystallization quenching method, it must be more than ten hours, which is not economic development. Isothermal annealing can greatly shorten the production cycle time and make all steel parts more symmetrical structure and characteristics. Isothermal annealing can also be reused in different stages of hot working of steel. For example, when air-cooled soft carbon steel is cooled from high temperature to indoor temperature, cracks will appear on the surface layer where austenite transformation has occurred when the careful part changes to austenite; if the hot ingot or billet of such steel is placed in an isothermal furnace above or below 800 C during the whole process of water cooling, the isothermal temperature will be maintained until the ferrite phase is formed. If air cooling is announced after the change is carried out, cracks can be avoided.