TRIBOLOGICAL PROPERTIES OF BRAKE DISCS COATED WITH Cr2O3–40% TiO2 BY PLASMA SPRAYING

2019 ◽  
Vol 26 (10) ◽  
pp. 1950075 ◽  
Author(s):  
BEKİR GÜNEY ◽  
İBRAHİM MUTLU
Keyword(s):  
Cast Iron ◽  
Plasma Spraying ◽  
Tribological Properties ◽  
Surface Hardness ◽  
Motor Vehicles ◽  
Brake Disc ◽  
Sem Images ◽  
Coating Materials ◽  
Coated Disc ◽  
Brake Discs

In this study, the tribological properties of Cr2O3–40% TiO2 coating for brake disc materials were investigated in braking performances. Plasma spraying technique was used in order to deposit coating materials onto cast iron disc with ventilation channels substrate. The braking performances of discs were tested according to SAE J2430 test standard. Microstructures of discs were characterized by means of light microscope (LM), scanning electron microscope (SEM) and energy-dispersive spectrometry (EDS). The surface hardness and roughness were measured with testers. In general, it is noted from the LM and SEM images that there was an infinite gradation between coating layer, binding material and the lamellar graphite cast iron and that bonding resistance was excellent. The coated disc exhibited less wear, approximately the same coefficient of friction and longer life than the uncoated disc. As a result, the coated disc could be a much better alternative for new-generation brake discs in the motor vehicles than the uncoated disc.

Modelling of grey cast iron for application to brake discs for heavy vehicles

2016 ◽  
Vol 231 (1) ◽  
pp. 35-49 ◽  
Author(s):  
Gaël Le Gigan ◽  
Magnus Ekh ◽  
Tore Vernersson ◽  
Roger Lundén
Keyword(s):  
Cast Iron ◽  
Elevated Temperatures ◽  
Kinematic Hardening ◽  
Frictional Heating ◽  
Material Model ◽  
Tensile Tests ◽  
Brake Disc ◽  
Brake Discs ◽  
Different Temperatures ◽  
Tension And Compression

Cast iron brake discs are commonly used in the automotive industry, and efforts are being made to gain a better understanding of the thermal and mechanical phenomena occurring at braking. The high thermomechanical loading at braking arises from interaction between the brake disc and the brake pads. Frictional heating generates elevated temperatures with a non-uniform spatial distribution often in the form of banding or hot spotting. These phenomena contribute to material fatigue and wear and possibly also to cracking. The use of advanced calibrated material models is one important step towards a reliable analysis of the mechanical behaviour and the life of brake discs. In the present study, a material model of the Gurson–Tvergaard–Needleman type is adopted, which accounts for asymmetric yielding in tension and compression, kinematic hardening effects, viscoplastic response and temperature dependence. The material model is calibrated using specimens tested in uniaxial cyclic loading for six different temperatures ranging from room temperature to 650 °C. A special testing protocol is followed which is intended to activate the different features of the material model. Validation of the model is performed by using tensile tests and thermomechanical experiments. An application example is given where a 10° sector of a brake disc is analysed using the commercial finitie element code Abaqus under a uniformly applied heat flux on the two friction surfaces. The results indicate that the friction surface of the hat side and the neck can be critical areas with respect to fatigue for the uniform heating studied.

EVALUATION OF THE HOMOGENEITY OF THE WORKING SURFACE OF CAST IRON BRAKE DISCS

Tribologia ◽  
2017 ◽  
Vol 276 (6) ◽  
pp. 33-37
Author(s):  
Grzegorz KINAL ◽  
Marta PACZKOWSKA
Keyword(s):  
Cast Iron ◽  
Corrosive Wear ◽  
Point Of View ◽  
Brake Disc ◽  
Braking Performance ◽  
Brake Pads ◽  
Braking System ◽  
Brake Discs ◽  
The One ◽  
Friction Surfaces

This article deals with the one of the most important elements of modern braking systems, which is a brake disc. A brake disc is the one of more stressed parts of the braking system, and its quality and design largely determine the braking performance of the vehicle. The article describes the technology of manufacturing disc brake pads that is important from the point of view of the wear processes occurring between two friction surfaces: the brake disc and the brake pad lining. The research of the cast iron ventilated brake disc surface measured the values of the selected roughness parameters at this site. In the context of measurements, it was also determined to be able to maintain a certain value of selected geometric parameters at a given location for the group of brake discs tested of a specific type and manufactured by a particular manufacturer. The work was carried out in the aspect of the research to create a surface layer to protect the brake discs from the effects of corrosive wear.

THE NEW INERTIA DYNAMOMETER FOR FRICTION AND WEAR TESTING OF BRAKE PADS AND BRAKE DISCS

Tribologia ◽  
2019 ◽  
Vol 286 (4) ◽  
pp. 113-119
Author(s):  
Waldemar TUSZYŃSKI ◽  
Michał GIBAŁA ◽  
Andrzej GOSPODARCZYK ◽  
Stanisław KOZIOŁ ◽  
Krzysztof MATECKI ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Friction And Wear ◽  
Wear Testing ◽  
Driving Safety ◽  
Brake Disc ◽  
Brake Pad ◽  
Vehicle Class ◽  
Brake Pads ◽  
Test Methodology ◽  
Brake Discs

For the sake of driving safety, the right choice of the brake pad friction material and its manufacturing processes to obtain the appropriate tribological properties is a matter of priority for brake pad manufacturers. Determination of the tribological properties is best done in component tests, i.e. in the setup: brake pads – brake disc. At the request of one of the domestic brake pad manufacturers, as part of the POIR project, an inertia dynamometer for testing friction and wear of brake pads and brake discs was developed and manufactured, which was given the symbol T-33. A test methodology was developed based on the “Cold application section” procedure described in SAE J2522:2003. The T-33 inertia dynamometer is designed for testing brake pads and brake discs intended for five vehicles representing the passenger vehicle class and vans. The paper presents the new test stand, test methodology, and results of verification tests of the T-33 dynamometer (interlaboratory comparison tests) performed on the Cinquecento vehicle brake setup.

scholarly journals Coatings for Automotive Gray Cast Iron Brake Discs: A Review

Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 552 ◽  
Author(s):  
Omkar Aranke ◽  
Wael Algenaid ◽  
Samuel Awe ◽  
Shrikant Joshi
Keyword(s):  
Cast Iron ◽  
Melting Point ◽  
Gray Cast Iron ◽  
Gray Cast ◽  
Exhaust Emission ◽  
Material Surface ◽  
Brake Disc ◽  
Braking Performance ◽  
Brake Discs ◽  
Disc Material

Gray cast iron (GCI) is a popular automotive brake disc material by virtue of its high melting point as well as excellent heat storage and damping capability. GCI is also attractive because of its good castability and machinability, combined with its cost-effectiveness. Although several lightweight alloys have been explored as alternatives in an attempt to achieve weight reduction, their widespread use has been limited by low melting point and high inherent costs. Therefore, GCI is still the preferred material for brake discs due to its robust performance. However, poor corrosion resistance and excessive wear of brake disc material during service continue to be areas of concern, with the latter leading to brake emissions in the form of dust and particulate matter that have adverse effects on human health. With the exhaust emission norms becoming increasingly stringent, it is important to address the problem of brake disc wear without compromising the braking performance of the material. Surface treatment of GCI brake discs in the form of a suitable coating represents a promising solution to this problem. This paper reviews the different coating technologies and materials that have been traditionally used and examines the prospects of some emergent thermal spray technologies, along with the industrial implications of adopting them for brake disc applications.

scholarly journals Modeling the Depth of Surface Cracks in Brake Disc

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3890
Author(s):  
Wojciech Sawczuk ◽  
Mateusz Jüngst ◽  
Dariusz Ulbrich ◽  
Jakub Kowalczyk
Keyword(s):  
Cast Iron ◽  
Crack Depth ◽  
Brake Disc ◽  
Disc Brake ◽  
Surface Cracks ◽  
Braking System ◽  
Brake Discs ◽  
Regression Functions ◽  
Metallic Object

The article presents the state of knowledge and research in the field of surface cracks occurring in disc braking systems of rail and car vehicles. The craze formed during the operation of vehicles is particularly dangerous and leads to breaking the disc into several pieces. It may lead to a loss of braking force and damage to the entire disc brake caliper. The main aim of the research is to identify surface cracks in brake discs made of cast iron and use experimental methods to estimate their depth. Research were conducted on the disc braking system developed by the authors. In examining the location and depth of cracks, the penetration method, ultrasound, as well as a special probe were used. This device measures the crack depth based on the electrical resistance between two points on the surface of the metallic object. The tests showed that the first microcracks on the brake discs appeared after 309 braking tests on the test stand. In addition, it was observed that the surface cracks length of the disc increased linearly to depth until they reached about 11.5–12 mm with corresponded to crack lengths in the range of 65–70 mm. However, determination of the regression functions presented in the article allows to estimate the depth of surface cracks up to 70 mm long on cast iron brake discs by measuring their length.

Performance of Hybrid Reinforced Metal Matrix Composite Brake Disc: Simulation Approach

2021 ◽  
Vol 1025 ◽  
pp. 77-81
Author(s):  
Wei Kang Gan ◽  
Nanang Fatchurrohman
Keyword(s):  
Cast Iron ◽  
Metal Matrix ◽  
Structural Performance ◽  
Brake Disc ◽  
Matrix Composites ◽  
Simulation Approach ◽  
Ansys Software ◽  
Braking System ◽  
Brake Discs ◽  
Usage Efficiency

A brake disc has an significant role in the vehicle and it is used to stop or decrease the velocity of the vehicle. The demand of metal matrix composites (MMCs) is greatly increased in fabricating the brake disc since it possesses a low density and high thermal conductivity. Over-heating will lead to the malfunction of the braking system and affect the safety of vehicle. Reduced weight of brake disc can decrease the use of fuel of the vehicle thus improve the fuel usage efficiency. This paper is focussed to determine the suitability of AlSiCGr hybrid MMCs compared to cast iron in terms of thermal and structural properties for brake disc. Both design of brake discs was proposed and modelled using CATIA and then imported to ANSYS software for structural and thermal analysis. The simulation results showed that AlSiCGr hybrid MMCs brake disc has higher thermal and structural performance compared to the original cast iron brake disc.

scholarly journals Simulation of thermal and mechanical performance of laser cladded disc brake rotors

2021 ◽  
pp. 135065012110091
Author(s):  
Nicholas Athanassiou ◽  
Ulf Olofsson ◽  
Jens Wahlström ◽  
Senad Dizdar
Keyword(s):  
Cast Iron ◽  
Laser Cladding ◽  
Adhesive Bonding ◽  
Mechanical Performance ◽  
Grey Cast Iron ◽  
Brake Disc ◽  
Particle Emissions ◽  
Brake Discs ◽  
Overlay Welding ◽  
Grey Cast

Disc brakes wear during braking events and release airborne particulates. These particle emissions are currently one of the highest contributors to non-exhaust particle emissions and introduce health hazards as well as environmental contamination. To reduce this problem, wear and corrosion-resistant disc coatings have been implemented on grey cast iron brake disc rotors by using various deposition techniques such as thermal spraying and overlay welding. High thermal gradients during braking introduce risks of flaking off and cracking of thermally sprayed coatings with adhesive bonding to the substrate. Overlay welding by laser cladding offers metallurgical bonding of the coating to the substrate and other benefits that motivate laser cladding as a candidate for the coating of the grey cast iron brake discs. This study aims to investigate the effect of laser cladding on the thermal and thermo-structural performance of the coated grey cast iron brake discs. Therefore, thermal and thermo-stress analysis with COMSOL Multiphysics 5.6 software is performed on braking events of grey cast iron brake discs as non-coated – reference and laser cladding coated with stainless steel welding consumables. The Results demonstrated that surface temperatures were more localised, overall higher in the laser cladded coating with over three times the stresses attained of reference grey cast iron discs. The output of the simulations has been compared by tests found in the literature. Laser cladding presented higher reliability and braking performance, nonetheless requiring the evaluation of its thermal impact on other system components.

scholarly journals Thermomechanical fatigue of grey cast iron brake discs for heavy vehicles

2017 ◽  
Vol 233 (2) ◽  
pp. 453-467 ◽  
Author(s):  
Gaël Gigan ◽  
Viktor Norman ◽  
Johan Ahlström ◽  
Tore Vernersson
Keyword(s):  
Cast Iron ◽  
Fatigue Life ◽  
Thermomechanical Fatigue ◽  
Grey Cast Iron ◽  
Life Assessment ◽  
Model Parameters ◽  
Brake Disc ◽  
Fatigue Life Assessment ◽  
Brake Discs ◽  
Grey Cast

The development of fatigue life assessment models for vehicle components exposed to thermomechanical fatigue supports the establishing of adequate maintenance intervals that neither cause unnecessary vehicle downtime, nor jeopardize the function of the components. In modern automotive applications, braking is closely related to safety and is commonly performed with disc brakes. Failure here may result in structural damage or even breakdown and loss of lives. In the present work, the cyclic response of grey cast iron is analysed and the fatigue life of brake discs made from this material is studied by use of four different fatigue life assessment models: the Smith–Watson–Topper model, the Coffin–Manson model and two mechanism-based damage models. Results from isothermal and thermomechanical experiments on uniaxially loaded specimens are used for calibration of the models. Finally, the models are used to assess the life of a brake disc for a simulated brake dynamometer experiment. It is found that the fatigue model parameters that are calibrated using different sets of isothermal uniaxial test data show a substantial spread. A comparison with results from full-scale brake rig experiments shows that predictions by any of the models that have been calibrated using data from a well-designed thermomechanical test are in reasonable agreement with the estimated crack initiation phase for actual brake disc lives. It can be concluded that it is not sufficient to calibrate the studied fatigue life models using isothermal uniaxial tests for predictions of thermomechanical fatigue lives.

scholarly journals Improvement in the brake disc design for heavy vehicles by parametric evaluation

2017 ◽  
Vol 231 (14) ◽  
pp. 1989-2004 ◽  
Author(s):  
Gaël Le Gigan
Keyword(s):  
Cast Iron ◽  
Fatigue Life ◽  
Thermal Loading ◽  
Grey Cast Iron ◽  
Brake Disc ◽  
Heavy Vehicles ◽  
Reference Case ◽  
Finite Element Software ◽  
Brake Discs ◽  
Grey Cast

Design of the brake disc geometry for a given brake disc material provides an opportunity for improvement in the fatigue life of the brake disc. High thermomechanical loads at braking lead to substantial local plastification and also induce tensile residual stresses in certain areas of the brake disc. This contributes to shortening of the fatigue life of the brake disc by possible initiation and growth of cracks. In the present paper, a simulation approach for evaluation of brake disc designs with respect to thermomechanical performance is developed and applied. Brake disc performance is analysed using commercial finite element software by employing a constitutive model for grey cast iron implemented in a Fortran subroutine. The thermal loading consists of consecutive severe braking cycles at a constant brake power and a constant speed, with cooling between the brake cycles. Based on a previous experimental study, three different assumptions are made regarding the spatial distribution of the thermal load at braking. A standard commercial brake disc made from grey cast iron having straight vanes is used as the reference case. Geometrical modifications are introduced in the ventilation arrangement using a design-of-experiments approach, studying both straight cooling vanes and different pillar layouts. A preliminary assessment of the fatigue life of the brake discs is carried out. The results indicate that the introduction of different pillar arrangements instead of straight vanes make it possible to decrease the mass of the brake disc by up to 13% or to increase the fatigue life of the brake disc by about 50%.

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