Low Temperature Carburizing Method for Uniform Layer Formation
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Solution Overview
Problem
Existing low-temperature carburizing methods face challenges in forming a uniform and high-quality carburizing layer on metals, particularly those with complex shapes, due to issues like natural oxide films and reduced corrosion resistance.
Innovation Solution
A low-temperature carburizing method involving pre-processing to remove natural oxide films, followed by a vacuum atmosphere and a mixed gas of hydrogen and acetylene at specific pressures for accelerated and spread carburization, with repeated cycles to enhance layer formation and hardness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high temperature carburizing is used, then carburizing speed is improved, but corrosion resistance deteriorates due to nitride and carbide precipitation
Solution Approach 1:
The patent changes the temperature parameter from conventional high temperature (900-1100°C) to low temperature (200-500°C) carburizing, fundamentally altering the process conditions to achieve both high carburizing speed and maintained corrosion resistance by preventing harmful phase precipitation
2Reliability
If low temperature carburizing is used, then corrosion resistance is improved, but carburizing layer formation becomes difficult due to natural oxide film
Solution Approach 1:
The patent applies preliminary action by performing pickling treatment before carburizing to remove the natural oxide film, creating a clean surface that enables effective low-temperature carburizing without the oxide film barrier
Solution Approach 2:
The patent changes the pressure parameter by applying vacuum (reducing pressure) during low-temperature carburizing, which prevents oxide film formation and enhances carbon diffusion into the metal surface, enabling effective carburizing layer formation at low temperatures
3Reliability
If vacuum atmosphere is used during low temperature carburizing, then oxide film formation is prevented, but process complexity increases
Solution Approach 1:
The patent uses vacuum atmosphere as an inert environment during low-temperature carburizing to prevent oxide film formation on the metal surface, creating optimal conditions for carbon diffusion without oxidation
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 method effectively forms a uniform carburizing layer with improved mechanical properties and corrosion resistance, suitable for metals with complex shapes, reducing the need for post-processing and enhancing carburizing ability.
Implementation Method 1
introducing a reaction gas thereinto at a predetermined pressure to accelerate carburization
Implementation Method 2
forming a vacuum atmosphere in the reaction chamber
Implementation Method 3
heating the same to a set temperature
Implementation Method 4
removing or weakening a natural oxide film by performing a pickling process for the metal to be processed
Data Source
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AI summary
A low temperature carburizing method according to the present invention comprises: step (a) for pre-processing a metal to be processed; step (b) for inputting the metal to be processed to a reaction chamber and heating the same to a set temperature; step (c) for forming a vacuum atmosphere in the reaction chamber and introducing a reaction gas thereinto at a predetermined pressure to accelerate carburization; step (d) for supplying the reaction gas to the reaction chamber at a pressure equal to or lower than the pressure of the reaction gas of step (c) to spread carburization; and step (e) for repeating step (c) and step (d) at predetermined time intervals.