Brake Disc Surface Hardening for Wear Resistance

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Solution Overview

Problem

Conventional brake discs experience high wear, corrosion, and overheating issues during braking, leading to reduced lifespan and potential brake failure due to inadequate surface hardening and friction properties.

Innovation Solution

A method for producing a brake disc using a metal material like gray cast iron, where the friction surfaces are treated through carbonizing, carbonitriding, case hardening, gas nitriding, or plasma processes to form a wear-resistant and corrosion-resistant hardened surface layer, enhancing the friction coefficient and reducing temperature buildup during braking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional brake disc materials are used without surface treatment, then manufacturing cost is low, but wear resistance and corrosion resistance are insufficient

Engineering Contradiction:

Improvewear resistanceVSAvoidmanufacturing complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The friction surfaces are subjected to surface hardening treatment (carbonizing, carbonitriding, case hardening, gas nitriding, oxide nitriding, gas nitro carburizing, plasma nitriding, plasma oxidizing, borating, plasma carborating, or plasma borating) during the manufacturing process to pre-establish wear-resistant and corrosion-resistant properties before the brake disc enters service

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The surface properties of the friction surfaces are modified by changing chemical composition and microstructure through diffusion processes, where atoms of carbon, nitrogen, boron, or oxygen are diffused into the surface layer to create hardened surfaces with enhanced wear and corrosion resistance

Inventive Principle:

Principle #35Parameter changes

2Duration of action of moving object

If the friction surfaces are hardened to reduce wear, then service life is extended, but the friction coefficient consistency may be affected

Engineering Contradiction:

Improveservice lifeVSAvoidfriction coefficient consistency

Core Design Contradiction:

Duration of action of moving objectVSManufacturing precision

Solution Approach 1:

Surface hardening treatment is applied specifically to the friction surfaces while leaving other parts of the brake disc unchanged, creating local differentiation where only the contact areas require enhanced hardness and wear resistance

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The surface hardening is performed during manufacturing to establish consistent friction properties before the brake disc enters service, ensuring uniform friction coefficient behavior across all brake discs of the same type

Inventive Principle:

Principle #10Preliminary action

3Reliability

If surface hardening treatment is applied to friction surfaces, then wear resistance improves, but manufacturing cost increases

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Various surface hardening methods are available ranging from conventional thermal processes (carbonizing, carbonitriding, case hardening, gas nitriding, oxide nitriding, gas nitro carburizing) to plasma-based processes (plasma nitriding, plasma oxidizing, plasma carborating, plasma borating), allowing selection based on cost-effectiveness and performance requirements

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The surface hardening treatment is integrated into the manufacturing process flow, performing the treatment in advance during production rather than as a separate post-manufacturing operation, which helps control costs through economies of scale

Inventive Principle:

Principle #10Preliminary action

4Temperature

If the brake disc structure is modified to improve heat dissipation, then brake fading is reduced, but device complexity increases

Engineering Contradiction:

Improvebrake temperatureVSAvoidbrake disc structure

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

Surface hardening treatment is applied locally to the friction surfaces where heat generation occurs during braking, creating a hardened layer that resists thermal damage and maintains friction properties at elevated temperatures, thereby preventing brake fading without requiring complex structural modifications

Inventive Principle:

Principle #3Local quality

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 results in a cost-effective brake disc with reduced wear, improved corrosion resistance, and consistent friction performance, preventing brake fading and enhancing braking comfort by minimizing vibrations and noise.

Implementation Method 1

a surface-near hardening of the friction surfaces is achieved, so that a wear-resistant and corrosion-resistant hardened surface layer is formed by atoms that are diffused in

Methodology Applied

Scientific EffectDiffusion: Diffusion

Implementation Method 2

the friction surfaces are after-treated by means of carbonizing, carbonitriding, case hardening, gas nitriding, oxide nitriding, gas nitro carburizing, plasma nitriding, plasma oxidizing, borating, plasma carborating or plasma borating

Methodology Applied

Scientific EffectCarbonizing: Carburizing

Implementation Method 3

Methodology Applied

Scientific EffectCarbonitriding: Carbonitriding

Implementation Method 4

Methodology Applied

Scientific EffectCase hardening: Case Hardening

Implementation Method 5

Methodology Applied

Scientific EffectGas nitriding: Nitriding

Implementation Method 6

Methodology Applied

Scientific EffectOxide nitriding: Nitriding

Implementation Method 7

Methodology Applied

Scientific EffectGas nitro carburizing: Carburizing

Implementation Method 8

Methodology Applied

Scientific EffectPlasma nitriding: Plasma

Implementation Method 9

Methodology Applied

Scientific EffectPlasma oxidizing: Plasma

Implementation Method 10

Methodology Applied

Scientific EffectBorating:

Implementation Method 11

Methodology Applied

Scientific EffectPlasma carborating: Plasma

Implementation Method 12

Methodology Applied

Scientific EffectPlasma borating: Plasma

Data Source

PatentUS8877296B2Method for producing a brake disc

Publication Date: 2014.11.04 MERCEDES BENZ GROUP AG

AI summary

A method for producing a brake disc (BS) for a vehicle, with a main body (G) of a metal material, in particular gray cast iron, which has friction surfaces (R). The friction surfaces (R) are coated with a coating of tungsten carbide, chromium carbide, and nickel or of tungsten carbide, cobalt and nickel and after-treated by carbonizing, carbonitriding, case hardening, gas nitriding, oxide nitriding, gas nitro carburizing, plasma nitriding, plasma oxidizing, borating, plasma carborating or plasma borating.