Temper Coils: Temper coils decrease the level of residual stresses set up during the hardening process without losing too much hardness achieved through induction. Temper coils also reduce the brittleness of a hardened component.
Annealing Coils:An Induction annealing coil is ideal for annealing cold worked materials. JO-MAR Industries, Inc. has developed coils to anneal parts with or without a controlled atmosphere.
Single Shot Coils: Single shot coils are used for hardening where the whole area to be hardened is heated at once.
Multi-Turn Coils: In multi-turn coils, as the heated length increases, the number of turns generally should increase in proportion. The multi-turn coil is generally utilized for large-diameter, single-shot heating, in which the quench medium can be sprayed between the coil turns. When the length of the coil exceeds four to eight times its diameter, uniform heating at high power densities becomes difficult. In these instances, multi-turn coils that scan the length of the workpiece are often preferable. Multi-turn coils generally improve the efficiency, and therefore the scanning rate, when a power source of a given rating is used.
Forge Coils:Forge coil components are commonly found at points of shock and stress such as wheel spindles, kingpins, axle beams and shafts, torsion bars, ball studs, idler arms, pitman arms and steering arms. Another common application is in the powertrain, where connecting rods, transmission shafts and gears, differential gears, drive shafts, clutch hubs and universal joints are often forged. Although typically forged from carbon or alloy steel other materials such as aluminum and microalloyed steels are seeing great advances in forged auto and truck applications. Forging is a manufacturing process where metal is pressed, pounded or squeezed under great pressure into high strength parts known as forgings. It is important to note that the forging process is entirely different from the casting process, as metal used to make forged parts is never melted and poured. The characteristics of forged parts, namely strength; reliability and economic stability are what makes them ideal for vital automotive and truck applications.
Split Return Coils: Split-Return Coils are used when a narrow band of heat is required and heating must be accomplished from one surface only, the split-return inductor offers distinct advantages. With this design, the center runner of the work coil carries twice the current of each of the return legs. The pattern on the workpiece, being a mirror image of the coil, produces four times as much heat under the center leg as in each of the return loops. With proper balancing, the high-heat path can then be extremely narrow, while the heat produced in each of the return legs is insufficient to affect the remainder of the part.
Channel Coils: When power densities are low and heating cycles not extremely short, parts can be processed by use of a turntable or conveyor in a continuous or indexing mode. The coil must be designed to permit easy entry and exit of the part. The simplest channel coil used in these situations is a modification of the hairpin inductor. With the indexing technique, in which the part is at rest in the coil during the heating cycle, the ends of the hairpin can be decoupled to prevent overheating of the ends. These raised portions or bridges also facilitate passage of the part through the coil. When a wide heating zone is to be produced on the part, coupling over a greater area can be accomplished through the addition of a liner to the coil turn, or more ampere turns can also be produced with a multi-turn channel inductor. Channel-coil liners may also be configured to produce specialized heating patterns where greater heat densities are required in specific areas.