Induction Heating Coil Segmentation for Quenching Temperature Control
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Solution Overview
Problem
Existing heat treatment methods for rod-shaped workpieces, such as cylindrical rollers, face challenges in efficiently achieving the desired temperature path for quench hardening due to high energy costs and difficulty in controlling temperature, particularly when using atmosphere heating furnaces or induction heating systems, which affects the mechanical strength and hardness of the final product.
Innovation Solution
A heat treatment apparatus comprising a conveying device and a heating coil with a first and second heating section, where the second section has a larger coil pitch than the first, allowing for efficient inductive heating and soaking of the workpiece at a quenching temperature, while being supported by a conveying device that rotates the workpiece to prevent temperature unevenness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If an atmosphere heating furnace is used to heat the workpiece to quenching temperature, then the workpiece can be heated uniformly, but a large amount of energy is required and the heating time is long
Solution Approach 1:
The patent replaces the traditional atmosphere heating furnace (thermal conduction system) with an induction heating system that uses electromagnetic fields to directly heat the workpiece. The induction heating apparatus generates eddy currents within the workpiece through a magnetic field, converting electrical energy directly into heat within the workpiece itself, thereby eliminating the need for prolonged thermal exposure and reducing overall energy consumption.
Solution Approach 2:
The patent utilizes the phase transition properties of electromagnetic fields to thermal energy through electromagnetic induction. By applying a high-frequency alternating magnetic field to the workpiece, the magnetic flux changes induce eddy currents that generate heat through resistive heating, achieving rapid temperature elevation to quenching temperature without the energy-intensive process of heating a large furnace chamber.
2Use of energy by stationary object
If induction heating is used to heat only the workpiece, then energy efficiency is improved and heating time is reduced, but it is difficult to control the temperature and achieve proper soaking
Solution Approach 1:
The heating coil is divided into multiple independent sections along the axial direction of the workpiece, with each section having a different coil pitch. The first heating section has a smaller coil pitch for rapid heating, while the second heating section has a larger coil pitch for controlled soaking at quenching temperature. This segmentation allows independent control of heating rates in different zones, achieving both rapid heating and precise temperature control.
Solution Approach 2:
Different sections of the heating coil are designed with different local characteristics (coil pitches) to perform different functions. The first section with smaller pitch provides intense localized heating, while the second section with larger pitch provides gentler heating for soaking. This local differentiation of heating characteristics enables precise control over the temperature path and soaking process.
3Productivity
If the heating coil has a small coil pitch for rapid heating, then heating efficiency is improved, but the workpiece cannot be maintained at quenching temperature for soaking
Solution Approach 1:
The heating coil is segmented into two distinct sections: the first heating section with small coil pitch for rapid heating to quenching temperature, and the second heating section with large coil pitch for maintaining the temperature during soaking. This segmentation allows the system to achieve both rapid heating and extended soaking at the target temperature.
Solution Approach 2:
The coil pitch is dynamically adjusted along the axial direction of the workpiece, transitioning from a smaller pitch in the first section to a larger pitch in the second section. This dynamic variation in coil pitch allows the heating intensity to be modulated along the workpiece length, enabling rapid heating followed by controlled soaking at the quenching temperature.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables efficient, cost-effective inductive heating of rod-shaped workpieces, ensuring high-quality mechanical components with desired mechanical strength and hardness, suitable for mass production.
Implementation Method 1
a heating device comprising a heating coil configured to inductively heat the rod-shaped workpiece being conveyed to a quenching temperature
Implementation Method 2
a heating device comprising a heating coil configured to inductively heat the rod-shaped workpiece being conveyed to a quenching temperature
Data Source
AI summary
Provided is a heat treatment apparatus (1), including: a conveying device (10), which is configured to convey a rod-shaped workpiece (W) at a predetermined velocity along an axial direction of the workpiece (W); and a heating device (2) including a heating coil (3) configured to inductively heat the workpiece (W) being conveyed to a quenching temperature, wherein the heating coil (3) includes a first heating section (3A) and a second heating section (3B), which are coupled to each other in series along the axial direction of the workpiece (W), and is electrically connected to a single high-frequency power supply (4), and wherein a coil pitch (D2) of the second heating section (3B) arranged relatively on a front side in a conveying direction for the workpiece (W) is larger than a coil pitch (D1) of the first heating section (3A) arranged relatively on a rear side in the conveying direction.