Many types of steel are treated with heat to increase toughness and resistance to wear. The effectiveness of this process depends on the steel's carbon content. When the steel is heated above its transformation temperature (720°C), the carbon changes the steel's crystalline structure to an austenite. The harder, more brittle steel is then quickly cooled or quenched.
To make the steel less brittle and more usable, another process called tempering is used; the steel is slowly heated to just below the transformation temperature and then slowly cooled.
There are two general types of hardening processes: through- hardening treats the entire part, while case-hardening generally treats the part surface area and some of the interior area, according to the depth of hardening requirements for a specific application.
Modern induction heating provides reliable, repeatable, non-contact and energy-efficient heat in a minimal amount of time. For hardening, induction provides the necessary control and accuracy to focus the heat to a specific area of the part. Solid state systems are capable of heating very small areas within precise production tolerances, without disturbing individual metallurgical characteristics.
For case-hardening, typical frequencies are 450 kHz for case-depths of 0.030" to 0.080"; thicker case-depths of 0.100 to 0.150" are typically hardened at 10 kHz. It is important to heat the part quickly with high power density, and then quench the part rapidly to prevent the inside of the part from exceeding the transformation temperature. Through hardening is generally defined more by the time required to heat through the part than the by the frequency of the power supply
Typical RF power supplies for hardening range from 5 to 120 kW, depending on the material and application requirements.
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|hardening||steel||hardening_10||Case hardening a steel fitting (machined parts manufacturer)||The coil design enabled the part to be raised into the heating coilfrom the bottom. The design was also made to ensure it will work well within the customer’s current setup...||apps_able.php||hardening.php||db_hardening.html|
|hardening||steel||hardening_9||Surface hardening of steel screws||Induction heating enables precise application of heat, faster process time and production rates and the ability to be incorporated into existing production lines||apps_able.php||hardening.php||db_hardening.html|
|hardening||steel||hardening_8||Hardening teeth on a steel motorcycle gear||A single turn helical coil is used to heat the gear. The gear is placed on a spindle and rotated at 300-350 RPM’s.||apps_able.php||hardening.php||db_hardening.html|
|hardening||steel||hardening_7||Hardening steel screw threads||A five turn helical coil is used heat the screw threads. The screw is placed in the coil, heat is applied for 8 seconds to achieve a 2” long zone at the required hardness.||apps_able.php||hardening.php||db_hardening.html|
|hardening||steel||hardening_6||Hardening the end of steel hand-held marking stamps||To harden various size ends of hand held marking stamps. The area to be hardened is 3/4” (19mm) up the shank.||apps_able.php||hardening.php||db_hardening.html|
|hardening||steel||hardening_5||Hardening of Steel Cam Assembly||Hardening the cam outer surfaces with induction results in uniform heating for uniform results, one coil can be used for many geometries, consistent results from piece to piece||apps_able.php||hardening.php||db_hardening.html|
|hardening||steel||hardening_4||Case Hardening of Armature Shaft||A five turn helical coil is used to heat the gear end of the shaft to 1700ºF||apps_able.php||hardening.php||db_hardening.html|
|hardening||cast iron||hardening_3||Hardening Cast Iron Pulleys||Heat cast iron pulleys to 1600ºF(871.1ºC) in order to achieve a hardness of 55 Rockwell C.||apps_able.php||hardening.php||db_hardening.html|
|hardening||steel||hardening_2||Hardening Stainless Steel Surgical Knife Blades||A two turn helical coil with an internal quartz tube designed to scan the length of the blade is used to heat the blade to 1850ºF (1010ºC) to achieve the desired hardness.||apps_able.php||hardening.php||db_hardening.html|
|hardening||steel||hardening_1||Hardening Bed Knife Blade for Reel Type Lawn Mowers||The hardness desired is between 45 to 55 Rockwell C, and should be measured 0.062"(1.6mm) from the cutting edge.||apps_able.php||hardening.php||db_hardening.html|