In addition to partial hardening of hollow and solid rack shafts using direct quenching, DKK can perform a wide range of heat treating operations, including full periphery traverse hardening using Dual Frequency Combined Heating.
We also have experience in the manufacture of non-oxygen hardening equipment using nitrogen gas for racks provided with ball screws in the shaft area which are used in luxury automobiles. The fastest processing time is 21 sec/unit.
We can propose a wide range of hardening methods to meet your needs.
Direct Resistance Heating Method
Hardening is performed by applying high-frequency current directly to the rack tooth and back surfaces. As hardening is performed only on the necessary portions, low-distortion machining is possible. We have a long and diverse track record of using this method.
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Induction Heating Method
Arbitrary distortion adjustment can be achieved by performing scanning hardening on the entire tooth and back surfaces and providing a mechanism to correct irregularities in the workpiece by applying pressure from the front, back, left, and right during heating. For ball-screw rack shafts, atmospheric hardening in nitrogen gas is also available to prevent oxidation during the heating process. Dual-frequency combined hardening, in which the tooth surface and ball-screw portions with different heat treatment specifications are processed with scanning hardening in a single step, is available as well.
![](https://denkikogyo.co.jp/wp-content/uploads/2022/08/21.jpeg)
What are Racks?
Racks are a component of the mechanism which converts the rotational motion of the steering wheel into reciprocating left-right motion in order to change the direction of the vehicle’s wheels.
![](https://denkikogyo.co.jp/wp-content/uploads/2022/08/86-1.jpeg)