Ring Workpiece Hardening Fixture with Controlled Quenching
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Solution Overview
Problem
Existing methods for hardening ring-shaped workpieces often result in significant distortion due to the use of pressure-tight quenching chambers and lack precise control over the quenching process, leading to uneven hardness and reduced toughness.
Innovation Solution
A fixture and method that utilize a mandrel and hold-down devices to maintain the workpiece's shape and apply cold gaseous quenching agents from opposite surfaces, allowing for controlled and reproducible quenching without a pressure-tight chamber, ensuring even cooling and reduced distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a pressure-tight quenching chamber is used for hardening ring-shaped workpieces, then the quenching process can be contained and controlled, but significant distortion occurs due to uneven cooling and lack of shape maintenance
Solution Approach 1:
The quenching chamber is segmented into multiple independent cooling zones with separate coolant supply and removal paths, allowing different regions of the workpiece to be cooled at different rates and temperatures, thereby maintaining shape while achieving precise hardening control
Solution Approach 2:
The workpiece is pre-positioned on a support structure before quenching begins, and cooling channels are pre-configured to direct coolant flow to specific areas, ensuring proper shape maintenance and uniform cooling distribution from the start of the process
2Productivity
If conventional quenching methods are used without precise control, then the process is simpler and faster, but uneven hardness and reduced toughness result from uncontrolled cooling
Solution Approach 1:
Temperature sensors are installed throughout the quenching chamber to continuously monitor the thermal state of the workpiece, and this feedback information is used to dynamically adjust coolant flow rates and temperatures in real-time, ensuring uniform hardness while maintaining high quenching speed
Solution Approach 2:
The quenching system transitions from static cooling conditions to dynamic control where coolant flow rates, temperatures, and channel configurations can be adjusted during the quenching process based on real-time temperature measurements, achieving both speed and precision
3Device complexity
If the workpiece is not constrained during quenching, then the fixture structure is simpler, but shape distortion increases due to thermal expansion and contraction
Solution Approach 1:
The constraint function is extracted from the quenching chamber walls and assigned to a separate, dedicated support structure that provides mechanical restraint independent of the cooling system, allowing the chamber to focus on temperature control while the support maintains shape
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
The solution achieves high precision hardening with reduced distortion, enabling better control over the quenching process and improved toughness by maintaining the workpiece's shape and applying gaseous quenching agents in a controlled manner.
Implementation Method 1
cold gaseous quenching medium is supplied to the workpiece's mutually opposing surfaces, and heated quenching medium is removed
Implementation Method 2
cold gaseous quenching medium is supplied at least to a radially inwardly directed inner surface of the workpiece and to a radially outwardly directed outer surface of the workpiece
Data Source
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AI summary
The fixture comprises a mandrel (1) disposed in the fixture, a force-pressurization device, conductive paths for supplying cold gaseous quenching agent to an annular workpiece (3) and for discharging heated quenching agent from the fixture, and radially outwardly directed nozzles. The mandrel is coaxially positioned to a rotational axis of the workpiece, and extends by its internal opening during hardening of the workpiece. The force-pressurization device comprises a support (2), and is mechanically movable along an axis of rotation of a blank holder. The fixture comprises a mandrel (1) disposed in the fixture, a force-pressurization device, conductive paths for supplying cold gaseous quenching agent to an annular workpiece (3) and for discharging heated quenching agent from the fixture, and radially outwardly directed nozzles. The mandrel is coaxially positioned to a rotational axis of the workpiece, and extends by its internal opening during hardening of the workpiece. The force-pressurization device comprises a support (2), and is mechanically movable along an axis of rotation of a blank holder. During hardening of the workpiece, a first end face (5) of the workpiece on the support rests, and a second end face of the workpiece opposing the first end face rests at the holder using force. The conductive paths define mutually opposing surfaces of the workpiece, and are partially formed inside of the mandrel. During supplying, the nozzles are arranged within the mandrel and configured for direct flow onto the radially inwardly facing inner surfaces of the workpiece with the gaseous quenching agent or the nozzles are formed in the support and the blank holder to direct flow onto the axially facing outer surfaces of the workpiece. The inner surface of the workpiece defines an inner opening in the workpiece, and is formed in the outer surface of the workpiece. The conductive paths are attached to the nozzles around in the direction of the workpiece. The nozzles are connected to conductive paths for supplying the liquid quenching agent and the receiving drops of the liquid quenching agent to the gaseous quenching agent, and are designed as a carrier medium. The fixture further comprises a temperature sensor for detecting temperature disposed on the workpiece, and a control and/or regulating device that is connected to the temperature sensor for adjusting the supply of quenching agent based on the temperature on the workpiece. An independent claim is included for a method for hardening a single annular workpiece.