Bearing Ring Heat Treatment with Selective Induction Hardening
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Solution Overview
Problem
The existing heat treatment methods for bearing rings, such as carburizing, are costly and time-consuming, and often fail to achieve optimal surface hardness, toughness, and fatigue life, leading to potential failures under impact loads.
Innovation Solution
A method involving induction heating and liquid spraying treatments to create hardened regions on a bearing ring with controlled temperature profiles, followed by low-temperature tempering, which allows for improved hardness and toughness distribution without the need for carburizing, significantly reducing treatment time and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If carburizing treatment is performed to achieve surface hardening and improved wear resistance, then surface hardness and wear resistance are improved, but treatment time is excessively long (at least 16 hours) and energy consumption is high
Solution Approach 1:
The patent replaces the chemical carburizing process with an induction heating-based surface hardening process. Induction heating uses electromagnetic fields to directly heat the bearing ring surface, achieving hardening without prolonged chemical treatment. This substitution reduces treatment time from 16+ hours to a fraction of that time while maintaining surface hardness improvements.
Solution Approach 2:
The patent changes the heating parameters by using induction heating at controlled temperatures and durations instead of prolonged carburizing. By adjusting induction heating power, duration, and cooling rates, the process achieves surface hardening in minutes rather than hours, fundamentally changing the time-temperature parameters of the heat treatment process.
2Strength
If carburizing treatment is performed to achieve surface hardening, then wear resistance is improved, but energy consumption increases by more than 60%
Solution Approach 1:
The patent substitutes the energy-intensive chemical carburizing process with induction heating, which uses electromagnetic fields for direct surface heating. This substitution dramatically reduces energy consumption by eliminating the need for prolonged high-temperature furnace operation and chemical atmosphere maintenance required in carburizing, achieving wear resistance improvements with 60% less energy.
Solution Approach 2:
The induction heating process rapidly heats and cools the bearing ring surface through controlled cycles, achieving hardening in minutes rather than hours. This 'rushing through' the heat treatment process in brief, intense cycles rather than prolonged gentle heating significantly reduces total energy consumption while maintaining the desired surface properties for wear resistance.
3Strength
If carburizing treatment is performed to create a hardened layer, then surface hardness is improved, but the process complexity and equipment requirements increase
Solution Approach 1:
The patent replaces the complex carburizing equipment (furnaces, chemical atmosphere control systems, gas supply apparatus) with relatively simple induction heating equipment (induction coils, power supply, control system). This substitution dramatically simplifies the process equipment while achieving the same surface hardening objective, reducing both capital investment and operational complexity.
Solution Approach 2:
The patent extracts and eliminates the unnecessary chemical carburizing step from the heat treatment process, retaining only the essential heating and cooling phases needed for surface hardening. By removing the complex chemical treatment component and keeping only the thermal processing elements, the process becomes simpler while maintaining effectiveness.
4Strength
If carburizing treatment is performed to achieve surface hardening, then wear resistance is improved, but subsequent heat treatments are still required to eliminate defects, increasing process steps
Solution Approach 1:
The patent extracts and eliminates the need for subsequent corrective heat treatments by using induction heating parameters that directly produce defect-free hardened surfaces. By optimizing the induction heating cycle (heating rate, peak temperature, holding time, cooling rate), the process achieves surface hardening without the microstructural defects that would require additional treatment steps, thereby improving manufacturing efficiency.
Solution Approach 2:
The induction heating process is designed to perform all necessary hardening and defect prevention in a single preliminary treatment step. By carefully controlling the heating cycle parameters from the outset, the process achieves the desired surface properties without requiring follow-up heat treatments to correct deficiencies, streamlining the manufacturing process.
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 method achieves hardness of 55-65 HRC in outer regions and 25-55 HRC in middle regions, increasing fatigue life by 15% while saving over 60% energy and enhancing manufacturing efficiency by at least 50% compared to carburizing processes.
Implementation Method 1
performing an induction heating treatment and a liquid spraying treatment on the bearing ring
Implementation Method 2
performing a liquid spraying treatment in at least a part of the first radial surface so that the temperature of the whole surface of the first radial surface does not exceed 150°C
Implementation Method 3
performing a low-temperature tempering treatment on the bearing ring
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The invention discloses a heat treatment method for a bearing ring, the method comprising the following steps: the first step: performing induction heating and liquid spraying on the bearing ring, so that a radially outer portion and/or a radially inner portion of the bearing ring is hardened, and a radially middle portion is hardened; the second step: performing induction heating on a radially side surface which one of the two hardened portions or the hardened portion in the first step is adjacent to, so that the temperature at the corresponding surface reaches 820°C-950°C, while performing liquid spraying on the other radially side surface opposite to said side surface, so that the temperature of the entirety of the other radially side surface does not exceed 150°C, and, for the region subjected to the induction heating treatment, performing liquid spraying treatment after the induction heating treatment, so that the bearing ring forms a hardened radially outer portion, a hardened radially inner portion, and a radially middle portion with a reduced hardness; the third step: performing low-temperature tempering on the bearing ring. The heat treatment method of the present invention can increase fatigue life, reduce manufacturing energy consumption, and reduce manufacturing cost.