Brake Disc Wear Layer Hardness Gradient for Crack Resistance
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Solution Overview
Problem
Friction brake bodies, such as brake discs, face challenges in maintaining wear resistance and crack resistance under thermomechanical stresses during braking, leading to potential crack propagation and reduced service life.
Innovation Solution
A wear protection layer with gradually increasing hardness from the base body to the friction contact surface, achieved through multiple layers with varying carbide-forming elements and carbon content, including vanadium, titanium, and chromium, which forms metal carbides and enhances crack resistance and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a wear protection layer with high hardness is applied to the friction contact surface, then wear resistance is improved, but crack resistance deteriorates
Solution Approach 1:
The patent applies a wear protection layer with locally varying hardness: the outer friction contact surface has high hardness (HV 800-1200) for wear resistance, while the inner region adjacent to the base body has lower hardness (HV 400-600) for crack resistance. This gradient hardness distribution allows each region to perform its specific function optimally without compromising the other.
Solution Approach 2:
The patent changes the hardness parameter of the wear protection layer by controlling the carbon content distribution. The carbon content decreases from the outer surface inward, creating a hardness gradient that transitions from high hardness at the friction surface to lower hardness near the base body, thereby resolving the contradiction between wear resistance and crack resistance.
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 effectively prevents crack propagation into the base body, maintaining mechanical strength and corrosion resistance, while maintaining friction performance during braking.
Implementation Method 1
During solidification, the carbide-forming elements react with carbon atoms of the base alloy to form finely distributed metal carbides in the wear-resistant layer, increasing the layer's hardness and thus its wear resistance
Implementation Method 2
The wear protection layer is produced on the base body, for example, by a laser deposition welding process
Data Source
Figure 1~2
AI summary
The invention relates to a friction brake body, in particular a brake disc (1), for a friction brake (3) of a motor vehicle, wherein the friction brake body has a main part (3) with at least one wear protection layer (5) on at least one frictional contact region of the main part (3), and the wear protection layer (5) forms a frictional contact surface (4) on the wear protection layer face facing away from the main part (3). According to the invention, the degree of hardness of the wear protection layer (5) increases incrementally or continuously from the main part (3) to the frictional contact surface (4).