Grey Cast Iron Brake Disc Nitriding for Low Thermal Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Grey cast iron brake discs suffer from low corrosion resistance, uneven nitride layer formation, and increased thermal deformation due to limitations in nitrogen diffusion and nitriding treatment processes.
Innovation Solution
A brake disc manufacturing method involving a casting step using grey cast iron with specific carbon and silicon content, followed by surface processing and nitriding treatment with a controlled nitriding gas composition and temperature, to form a thick and uniform nitride layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nitriding treatment is performed on grey cast iron brake disc surface, then corrosion resistance is improved, but nitrogen diffusion is inhibited by pearlite and graphite structure resulting in shallow and uneven nitride layer
Solution Approach 1:
The patent modifies the chemical composition parameters of the grey cast iron, specifically controlling carbon content at 2.5-3.5 wt%, silicon at 1.0-2.0 wt%, and manganese at 0.5-1.5 wt%, to optimize the matrix structure for improved nitrogen diffusion while maintaining the grey cast iron characteristics
Solution Approach 2:
The patent applies surface preprocessing steps including shot blasting or sand blasting before nitriding treatment to create a roughened surface that enhances nitrogen absorption and promotes more uniform nitride layer formation throughout the treatment process
2Reliability
If nitriding treatment parameters (nitrogen potential, temperature, time) are increased to thicken nitride layer, then corrosion resistance improves, but thermal deformation increases causing noise and judder
Solution Approach 1:
The patent optimizes the nitriding treatment parameters within specific ranges: nitrogen potential Kn of 3-5, temperature of 500-550°C, and time of 2-4 hours, achieving an balanced nitride layer thickness of 5-15 μm that provides adequate corrosion resistance while minimizing thermal deformation and associated noise and judder
Solution Approach 2:
The patent employs continuous nitriding treatment with controlled gas flow and temperature maintenance throughout the process, ensuring uniform nitrogen diffusion and consistent nitride layer formation that prevents localized overheating and thermal deformation
3Object-affected harmful factors
If red rust forms on brake disc surface during low-frequency braking, then anti-rust treatment is required, but frequent braking prevents red rust conversion to black rust through friction
Solution Approach 1:
The patent extracts and addresses the rust prevention function separately from the braking function by applying a dedicated anti-rust coating or surface treatment layer that provides corrosion protection without interfering with the braking performance or requiring additional maintenance interventions
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 achieves improved corrosion resistance, wear resistance, and reduced thermal deformation of the brake disc, ensuring enhanced braking performance and durability.
Implementation Method 1
a nitriding treatment step of forming a nitride layer by subjecting the disc body
Implementation Method 2
Pearlite and graphite, which make up the matrix structure of grey cast iron, have a problem of inhibiting diffusion of nitrogen
Data Source
AI summary
A brake disc, and a method of manufacturing the same, yield a brake disc capable of exhibiting low thermal deformation and superior wear resistance and corrosion resistance using a new composition for grey cast iron and through nitriding gas treatment thereof.