Hollow Spring Member Carburization via Sealed Gas Atmosphere
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Solution Overview
Problem
Existing methods for hardening the inner surface of hollow spring members, such as those used in vehicle suspension systems, are inefficient and costly, particularly due to the need for dedicated carburizing furnaces and uneven carbon distribution, which prolong production time and increase energy consumption.
Innovation Solution
A method where a carburizing gas is sealed within the steel tube and heated to carburize the inner surface, allowing for simultaneous carburization and quenching without a dedicated furnace, using a gas replacement device to maintain a controlled atmosphere and reduce energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a liquid carburizing agent is attached to the steel tube inner surface by immersion or application, then the carbon concentration is increased to enhance hardness, but the amount of carbon becomes excessive and the carbon concentration becomes uneven, causing excessively hardened positions that reduce toughness
Solution Approach 1:
The patent uses a gas-phase carburizing agent (carburizing gas) instead of liquid immersion or application methods. The gas flows through the steel tube interior, providing uniform carbon distribution through gas-phase diffusion, which prevents excessive localized hardening and maintains toughness while achieving the desired hardness enhancement.
2Manufacturing precision
If a dedicated carburizing furnace is used to carburize the hollow spring member, then the carbon concentration is increased to improve hardness, but the equipment cost and energy consumption increase significantly
Solution Approach 1:
The patent combines the carburizing process with the existing heating process by introducing the carburizing gas during the heating stage. This integration eliminates the need for a separate dedicated carburizing furnace, reducing equipment costs and energy consumption while achieving the desired surface hardening effect.
3Manufacturing precision
If batch-wise carburization in a furnace is performed, then the carbon concentration is increased to enhance hardness, but the production time is prolonged
Solution Approach 1:
The patent implements continuous carburization by flowing the carburizing gas continuously through the steel tube interior during the heating process. This continuous action eliminates the batch-wise processing delays associated with traditional furnace methods, reducing production time while maintaining consistent surface hardness quality.
4Ease of manufacture
If the steel tube inner surface is not treated with compression stress methods, then the manufacturing process is simpler, but the resistance to fatigue is reduced due to decarburization at high temperature
Solution Approach 1:
The patent applies preliminary carburization to the steel tube inner surface before final heat treatment. By increasing the carbon concentration in advance during the heating stage, the steel gains improved hardenability and fatigue resistance, eliminating the need for subsequent compression stress treatments while maintaining manufacturing simplicity.
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 approach reduces production time and energy costs by enabling efficient carburization and quenching within the hollow spring member, while maintaining a rust-preventive atmosphere and ensuring consistent carbon distribution, thereby enhancing the hardness and toughness of the steel tube inner surface.
Implementation Method 1
a carburizing gas sealed in the interior space of the steel tube
Implementation Method 2
carburize part of the carburizing gas into the inner surface of the steel tube
Implementation Method 3
heating for austenitization is performed on the hollow spring member
Implementation Method 4
when quenching is carried out at an ideal cooling rate, the degree of hardness of steel is determined by a carbon concentration
Data Source
AI summary
A hollow spring member and hollow spring member production method can be provided, which can save the time and energy necessary for carburization, thus requiring no dedicated carburizing furnace or the like for carburization, and further can make the interior space of a steel tube a rust-prevention atmosphere. A hollow stabilizer for a vehicle includes a steel tube sealed at one end and another end thereof and a carburizing gas sealed in the interior space of the steel tube.