Germany eldec synchronous dual-frequency induction hardening technology is mainly used in the automotive industry, mold manufacturing, aircraft manufacturing, electrical and mechanical manufacturing generators and transformers.
SDF contour quenching technology
For a workpiece having a concave-convex surface structure like a gear, conventional single-frequency induction heating technology cannot achieve satisfactory processing results. Since the gear has a convex surface and a concave surface, the surface of the gear is quenched by high-frequency induction heating, and the heat generated by the induced current is rapidly transmitted to the center of the tooth, and the crown is completely hardened, but the root hardening is insufficient. In addition, this treatment method tends to increase the residual stress on the root tooth surface, resulting in the occurrence of fracture. The surface is quenched by medium frequency induction heating, and the heat is conducted at the root. Due to the concave shape of the root, the heat transfer process is exponentially decreasing, the root is effectively hardened, and the crown is insufficiently hardened. With an adjustable intermediate frequency and high frequency ratio, the intermediate frequency and high frequency are output on an induction heater, and the tooth top and root of the gear are uniformly heated to obtain a balanced contour hardened layer.
SDF® (Simultaneous Dual Frequency) generates intermediate frequency and high frequency currents simultaneously on an induction coil, induces eddy current on the surface of the workpiece, rapidly heats the surface of the workpiece in a very short time, and then rapidly cools to obtain contour hardening on the surface of the workpiece. Layer induction hardening technology. SDF® technology features: IGBT transistor, synchronous dual-frequency induction heating, very short heating time (0.2 ~ 0.3s), small deformation, hardening along the contour, high thermal efficiency, and small environmental pollution.
Comparison of heat treatment processes
Compare the three quenching processes of carburizing and quenching (contour quenching), single frequency induction quenching (non-contour quenching), and simultaneous dual-frequency quenching SDF® (precise contour quenching).
The process principle of carburizing and quenching (contour quenching) is to heat the carburizing furnace to above Ac3, and the liquid or gas is rapidly cooled and tempered to obtain the required mechanical properties; the suitable material is C<0.25% carbon steel, such as 5115 (16MnCr5). ); high deformation; high flexibility, high environmental impact, low energy efficiency; quenching time of up to ten hours, local quenching feasibility is extremely low.
Single-frequency induction hardening (non-contour quenching) is to induce a single-frequency eddy current at the edge of the workpiece. The fluid is rapidly cooled and tempered to obtain the required mechanical properties. The suitable material is C<0.35% carbon steel, such as 1040 or 4140 (42CrMo4). ); deformation is not too high, insufficient hardening; high heat treatment capacity, low flexibility, low environmental impact, high energy efficiency; quenching time 30 ~ 60s, local quenching is more feasible.
Synchronous dual-frequency quenching (precise quenching) is to induce dual-frequency eddy current at the edge of the workpiece, the fluid is rapidly cooled and tempered to obtain the required mechanical properties; suitable for single-frequency induction hardening process; low deformation; heat treatment capacity Extremely high, flexible, environmental impact is extremely low, energy efficiency is high; quenching time <30s, local quenching is highly feasible.
In addition, the induction hardening machine has been modularized and integrated into the production line for flow-through operations and improved work efficiency.
SDF technology application
Boeing Company of the United States is based on the requirements for product quality and environmental protection. Some of its gears, such as straight umbrella (cone) gears, use SDF induction hardening technology instead of the original carburizing and quenching process. In fact, some of the workpieces are similarly heat treated after heat treatment. The toothing process will no longer need to be carried out. The world famous German BMW (BMW) car manufacturer, German (Volkswagen) car manufacturer, Audi, BOSCH, Siemens, etc. have used this technology, and there are already enterprises in the country. After the workpiece processed by the synchronous dual-frequency induction heating technology, the slice can be seen to be particularly uniform in the hardened layer, suitable for gears, worms, hypoid gear shafts, steering gears of automobiles, automobile CV joints and drive shafts, diameters of 6 or less. A large number of complex contoured parts, such as the end faces of holes of different sizes.
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