Rail Profile Reconstruction via Sacrificial Layer Tempering
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Solution Overview
Problem
Existing methods for reconstructing rail profiles using build-up welding result in high martensite formation, leading to brittleness and reduced material quality, with preheating limitations that prevent effective reduction of martensite in covered areas due to temperature constraints.
Innovation Solution
A method involving the application of multiple metallic layers, followed by a sacrificial layer on the cover layer to induce a tempering process, combined with preheating at a low temperature (less than 80 °C) to reduce martensite content and improve material quality, while minimizing damage to surrounding components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preheating is performed at high temperatures (300-400°C) to reduce martensite formation, then material quality improves, but surrounding components and construction elements are damaged
Solution Approach 1:
The patent applies different temperature treatments to different regions: the covered area undergoes build-up welding at lower preheating temperatures (≤80°C) to protect surrounding components, while the open superstructure allows higher preheating temperatures for better material quality. This local differentiation resolves the contradiction between material quality and protection of surrounding components.
Solution Approach 2:
The patent introduces a sacrificial layer as an intermediary between the build-up welding layers and the final surface. This sacrificial layer absorbs the thermal stress and prevents direct heat exposure to surrounding components during the welding process, enabling lower preheating temperatures in the covered area while maintaining material quality.
2Object-affected harmful factors
If preheating temperature is limited to ≤80°C to protect surrounding components, then damage to surrounding structures is minimized, but martensite formation increases leading to brittleness
Solution Approach 1:
The patent applies different temperature treatments to different regions: the covered area undergoes build-up welding at lower preheating temperatures (≤80°C) to protect surrounding components, while the open superstructure allows higher preheating temperatures for better material quality. This local differentiation resolves the contradiction between material quality and protection of surrounding components.
Solution Approach 2:
The patent changes the material parameters by introducing a sacrificial layer with specific properties (different composition and hardness) between the build-up welding layers and the final surface. This sacrificial layer undergoes tempering during welding, which indirectly treats the underlying layers and reduces martensite formation even at lower preheating temperatures, thus reducing brittleness while maintaining low preheating temperatures.
3Manufacturing precision
If multiple layers are applied to reconstruct the rail profile, then worn areas are filled, but martensite formation increases causing cracking
Solution Approach 1:
The patent introduces a sacrificial layer as an intermediary between the build-up welding layers and the final surface. This sacrificial layer absorbs the thermal stress and prevents direct heat exposure to surrounding components during the welding process, enabling lower preheating temperatures in the covered area while maintaining material quality.
Solution Approach 2:
The patent changes the material parameters by introducing a sacrificial layer with specific properties (different composition and hardness) between the build-up welding layers and the final surface. This sacrificial layer undergoes tempering during welding, which indirectly treats the underlying layers and reduces martensite formation even at lower preheating temperatures, thus reducing brittleness while maintaining low preheating temperatures.
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 significantly enhances the material quality of the reconstructed rail, reducing cracking and extending its service life with reduced effort and lower preheating temperatures, ensuring fewer damages to surrounding structures.
Implementation Method 1
By applying the so-called sacrificial layer on the cover layer it is achieved that the sacrificial layer heats up the layers below, which leads to a tempering process that reduces the martensite content in the layers below
Implementation Method 2
The section of the rail to be reconstructed is further warmed up to a predetermined preheating temperature before the individual layers are applied
Data Source
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AI summary
Method for reconstructing the rail profile of worn rails (1), comprising the following steps: applying several superimposed layers (8a - 8x) of metallic material (14) to a worn area (10, 11, 12) of the rail (1), up to the application of a top layer (20) that protrudes outwards beyond a desired nominal profile (13) of the rail (1); applying at least one further layer (40) of a metallic material (14) to the top layer (20) and removing the protruding material (14) until the nominal profile (13) is achieved.