Gray Iron Research Articles

Parametric Characterization of Machined Textured Surfaces

Surface topography in general is not easy to characterize due to a great number of different features that appear on it. It is still more challenging for machined textured surfaces that are of high functional significance for tribological purposes. For practical reasons, there is a need to describe such surfaces using only a small number of parameters. Which of them represent surface details the best is still an open issue. To find out which parameters can be the most suitable in that case, three groups of machined textured surfaces were prepared. They were plateau-honed cylinder surfaces made of gray cast iron, steel, and bronze surfaces with isolated dimples and steel surfaces after abrasive blasting followed by lapping. All of them were measured by means of a white light interferometer. Different parameters and relationships were evaluated and based on them correlation and regression analyses were used. The basic description contained statistically independent parameters that can be used in production control, while the wider description in scientific research. In general, parameters of random surfaces were more intercorrelated than those of surfaces with isolated dimples. As was found for the basic description of random two-process surfaces, five parameters were enough while description of textured surfaces with isolated oil pockets needed six. In wider, scientific description, regardless the surface type seven parameters contained the necessary information about the surface. It was also proved that a pair of parameters, the emptiness coefficient Sp/Sz and Sq/Sa, can describe the shape of the ordinate distribution of machined textured surfaces better than, for example, skewness Ssk and kurtosis Sku, commonly used for that purpose.

Analysis of the effect of ventilation hole angle and material variation on thermal behavior for car disc brakes using the finite element method

Brakes are used to slow down or stop a moving object. The temperature of the disc brake will rise as a result of the conversion of kinetic energy from vehicle speed into thermal energy during the braking operation. To prevent harm to the disc brake or other components, the heat generated by this disc brake must then be released into the environment. Therefore, it is crucial to provide effective heat dissipation to the environment. Increasing the surface area where heat is dissipated into the environment is one potential solution. In this study, the variation of the drill hole angles and groove hole angles is proposed as a geometry modification to encourage greater heat dissipation in disc brakes. In addition, the thermal performance of disc brakes made from various types of materials is assessed using finite element analysis. The materials employed are carbon ceramic, stainless steel, and gray cast iron. The numerical findings show that the groove-type disc brake with a ventilation hole angle of 0° angle has the lowest maximum temperature. In addition, it is revealed that the disc brake made of gray cast iron material results in the lowest peak temperature. The numerical results also indicate that due to the thinning of the geometry, the addition of the ventilation hole angle contributes to the phenomena of temperature concentration in specific areas of the disc brake. This study demonstrates that disc brake material and ventilation hole play a significant effect in altering the thermal characteristics.

Evolution of microstructure and high temperature tensile strength of gray cast iron HT250: The role of molybdenum

The present work investigated the influence of molybdenum (Mo) content on the microstructure and high temperature tensile strength (HTTS) of gray cast iron (GCI) to achieve improvement of the HTTS of GCI brake drum for heavy-duty trucks and extension of their service life. The specimens of GCI with Mo (0.024%, 0.22%, 0.51%, 0.8%) have been prepared by smelting in a 25 kg vacuum induction furnace and casting in a standard mold. The microstructure was observed by scanning electron microscopy and optical microscopy, while physical properties tested by microcomputer-controlled testing machine and micro hardness tester. The results show that increasing the Mo content from 0.024% to 0.8%, the length of graphite flake decreased from 400 μm to 288 μm; the pearlite interlayer spacing decreased from an average of 619 nm–439 nm. However, the pearlite content also decreased with the increase of the Mo content. A portion of the Mo is in solution in the matrix; this contributes to solution strengthening of the matrix. The remainder of the Mo precipitates in the austenite grains, or the grain boundaries, as carbides. This results in the refining of the pearlite grains. Eutectic cell density increased from 217 cm−2 to 286 cm−2. Both room temperature tensile strength and HTTS increased with increasing Mo content. The findings suggest adding Mo to GCI is an effective way to improve the microstructure and increase its HTTS.

Влияние комплексного модифицирования на структуру и свойства серого чугуна триботехнического назначения

Introduction. An approach based on the complex modification of cast irons makes it possible to improve its mechanical properties by changing the structure of the metal matrix, as well as the shape of graphite and its distribution. The aim of this work is to study the influence of alloying elements on the structure and mechanical properties of gray cast irons obtained for operation under friction wear conditions. Research methods. The paper describes the process of obtaining complex modified gray cast irons. Fractographic investigation of dynamically destroyed samples is carried out. Structure’s features of SCh35, ChMN-35M and SChKM-45 gray cast irons are studied. Tribological testing under sliding friction conditions is carried out. Results and its discussion. It is established that the complex modification of SCh35 gray cast iron with molybdenum, nickel and vanadium makes it possible to increase its hardness to 295 HB and tensile strength to 470-505 MPa. Alloying with nickel (0.4-0.7 wt.%), molybdenum (0.4-0.7 wt.%) and vanadium (0.2-0.4 wt.%) leads to a decrease in the interlamellar distance of perlite by 2 times, as well as to the metal matrix grain refining. The length of graphite lamellas of modified cast irons is reduced by 3-5 times. An additional effect on the tensile strength of cast iron is due to the alloying of ferrite with molybdenum and vanadium, which is fallen out along the boundaries of graphite inclusions. Alloying of ferrite with molybdenum and vanadium increases the level of its microhardness by 1.4 times in comparison with the α-phase of SCh35 serial cast iron. The results of tribotechnical tests of the designed materials are presented. Conclusions. It is established that the wear of specimens made of SChKM-45 cast iron is approximately 20-30% lower compared to cast iron SCh35 cast iron and 10-15% lower compared to ChMN-35M cast iron. Fractographic studies show that complex alloying with molybdenum, vanadium and nickel, contributing to the refining of pearlite colonies, leads to a decrease of the size of the cleavage facets.

Performance comparison between internally cooled tools and flood cooling during grey cast iron turning

High heat generation with the consequent increase in temperature is still a limiting factor for productivity and quality in machining processes, mainly because it strongly affects the tool's life and the quality of the workpiece. Cutting fluids in abundance (CFA), often named flood cooling, is the standard machining cooling technique used industrially. However, CFA poses significant environmental hazards while incurring mounting manufacturing costs. To address this, the current paper focuses on a comprehensive performance evaluation of a novel internally cooled tool (ICT) while machining grey cast iron - GCI. Designed and built in-house, the ICT system can internally circulate the coolant through a specifically modified insert, effectively removing the heat from the interface. The machining tests followed a full factorial Design of Experiment- DoE (23) with two quantitative input variables, the depth of cut (doc) (1.0 and 2.0 mm) and the cutting speed (vc) (100 and 150 m/min) and one qualitative variable, the cutting atmosphere (ICT or CFA). The feed rate was maintained constant at 0.1 mm/rev. The response variables were cutting force, tool wear mechanisms, and surface integrity in terms of roughness, microhardness, and microstructure. The main results indicated that, compared to CFA, ICT increased cutting force by 42 %. ICT also increased peak microhardness by 22 % at 500 μm from the top surface. It also induced grain modification at 4 mm depth, indicating that ICT caused a work-hardening effect in the subsurface. These results were an indication that ICT could effectively take heat away at the cutting zone. Statistical analysis on surface roughness showed that the significant variables were the cutting speed and its interaction with the atmosphere, where increasing the cutting speed was the dominant parameter. ICT reduced the roughness at higher cutting speeds, as opposed to CFA. The predominant wear mechanisms were adhesion and abrasion, along with plastic deformation for both ICT and CFA. Finally, the ICT system showed to be a promising eco-friendly technique with high cooling capacity, presenting some advantages compared to CFA, with similar machining performance.

Effect of Material and Fin Geometry of Effectiveness of 100 CC Small Motorcycle Automobile Cylinder

In the case of design of a small two-wheeler, designing a cylinder and its cooling system is a big deal for engineers and researchers. To have a stable combustion in case of SI engine, the temperature at any point of cylinder can’t be raised to auto ignition temperature of the fuel. Thus, the cooling system of engine must be properly designed. When designing cylinder of two-wheeler, the choice is very limited. The fins can be an important technique for engine cooling. This paper presents a comparative study of magnesium alloy and grey cast iron (GCI) alloy as probable cylinder materials and rectangular, triangular and Trapezoidal shape as fin geometry. The solid geometry of cylinder having different types of extended surface was prepared in Solidworks and imported to ANSYS for further processing. The GCI alloy found to be better than magnesium alloy and the rectangular fin profile gave the least total heat flux.

Production of Lamellar Cast Iron EN-GJL-150 From Local Manganese-Rich Pig Iron by Modification of the Melting Process

Abstract In the present study, a modified duplex melting process was set up so as to be able to produce an EN-GJL-150 gray cast iron from a local manganese-rich pig iron. A descriptive statistics showed an average Mn and Si content in raw material such that: Mn % = 2.457±0.133 and Si % = 0.682±0.088. The demanganization process was run and monitored in a cascade of two industrial-scale furnaces: a rotary kiln and an electric arc furnace. The performed experiments indicated that: 1) the manganese content decreased from 2.45 % to 0.94 %, 2) the manganese oxidation obeys the first order kinetic model, 3) Brinell and Rockwell hardness’s decreased by 38.83% and 27.81% respectively, and 4) the produced cast iron has a pearlitic microstructure with a small fraction of ferrite (1 to 5%) in the matrix and traces of cementite. All results showed that the produced castings comply with the standards in force for EN-GJL-150 cast irons, similar to gray cast iron ASTM A48 Class 20.

Meta-analysis of the influence of different element contents on selecting the prediction model of gray cast iron’s elastic modulus

In order to explore the influence of different element contents on selecting the prediction model of gray cast iron’s modulus, we apply Meta-analysis to retrieve Chinese journals related to gray cast iron and elastic modulus and adopt fixed effect models to evaluate and analyze the introducedδ value, hoping to provide theoretical basis for prediction model of elastic modulus. According to the analytical results: (1) When the silicon content is relatively low, the model E0=101.32+2.51Si/C is suggested for prediction. (2) When the carbon content is relatively low, the model E0=313.175-49.014C-14.082Si is suggested for prediction. (3) When the two elements are both relatively low, Si/C value-based judgment needs to be made that the model E0=101.32+2.51Si/C is suggested when the value is relatively low. (4) When either the silicon content or the CE (carbon equivalent) is relatively low, the model E0=194.55-27.85CE+58.2Si/C or the model with three variables-E0=20.527-0.021Si/C+59.2841Si+0.004CE is suggested for prediction. (5) When some of the above cases exist simultaneously, the preferable model selection should be considered in the following order of priority: C=Si>Si/C>CE>S.

Electrochemical and weight loss studies of the corrosion profiles of gray cast iron under the influence of water hyacinth plant extract in 0.5 M NaOH

In an alkaline media (0.5 M of sodium hydroxide solution) with and without hot water digested water hyacinth plant extract (DWHPE) as an inhibitor, at various concentrations of 5 g, 10 g, 15 g, 20 g, and 25 g, the extent of gray cast iron corrosion was investigated in this study. The optical micrographs of the least (sample DWHPE-25 g) and most corroded (control) samples were investigated using optical microscopy. The least corroded sample showed minimum localized form of corrosion compare to the control under the micrograph view. With the use of the electrochemical polarization (EP) at a scan rate of 10 mV/s, and the weight loss (WL) method, the rates of corrosion of the working samples were investigated. For the control sample, these values were 3.36456 mmpy (obtained via WL), -543.643 mV (via EP), and 0.054556 mmpy (via EP). The corrosion rate via the WL and EP was, however, significantly reduced at 25 g of DWHPE, with values of 1.27200 mmpy and 0.023731 mmpy, respectively, at a greater corrosion potential of -283.86 mV.

DURA-BAR 202 (TYPE 2) Ni-RESIST IRON

Abstract Dura-Bar 202 (Type 2) Ni-Resist Iron is a flake graphite austentic cast iron that is produced by the continuous casting process. It is suitable for most applications requiring Dura-Bar 201 (Type 1) Ni-Resist Iron, and the grades are often used interchangeably. The machinability of Dura-Bar 202 (Type 2) Ni-Resist Iron will be similar to the pearlitic grades of gray iron, namely G2 and G2A. It is especially suitable for service temperatures above 705°C (1300°F) and in the stem handleing applications. Copper levels are maximized at 0.50%, and this grade is suitable for food grade applications. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as heat treating. Filing Code: CI-100. Producer or source: Dura-Bar Metal Services.

Comparison of Microstructure, Yield Strength, Tensile Strength, and Modulus of Elasticity between Gray Cast Iron and Nodular Cast Iron

Gray cast iron has graphite flakes which makes it relatively weak and brittle. The addition of magnesium to gray cast iron resulted in nodular cast iron which has spherical graphite. The aim of this research was to investigate the changes in the microstructure and strength due to the addition of magnesium to gray cast iron. Microstructure observations were made by metallographic testing using Scanning Electron Microscopy and Energy Dispersive Spectroscopy. Tensile testing was carried out to measure the yield strength, tensile strength, and modulus of elasticity. The addition of magnesium to gray cast iron was observed to increase the yield strength by 179%, tensile strength by 238%, and decrease the modulus of elasticity by 94%.

The Influence of Steel and Cast Iron as Substrate Materials on the Microstructure, Microhardness and Wear Resistance of Nickel-base Ti-Al Plasma Spray Coatings

This paper studies the influence of different substrate materials on the phase composition, microstructure, microhardness, and wear resistance of Ni-Cr-B-Si-C-Ti-Al plasma spray coatings. Two types of substrate metals were studied – AISI 1045 steel and Pig-P3 Si grey cast iron. It has been found that in the as-coated condition the surface layers have a phase composition of γ-Ni, Cr23C6, γ-TiAl, TiN, and α-Ti(N, O) on steel substrate, and γ-Ni, α-Ti, TiN, Ni3B, CrB, Cr23C6, α-Ti(N, O), Ni3Si on cast iron. The microhardness and wear resistance of the plasma sprayed Ni-Cr-B-Si-C-Ti-Al coatings is tested. The wear volume of the coatings has been tested for up to 60 min. The deposits on cast iron substrates demonstrate lower wear than those on the steel substrate.

COMPOSITE MATERIAL WITH CAST IRON MATRIX DESIGNED FOR BRAKE SYSTEMS OF TECHNICAL MEANS OF TRANSPORT

The paper presents the basics of manufacturing and the tribological properties of the developed cast ironceramic composite designed for brake discs or drums. The matrix of the composite consists of GJL-150 grey cast iron used for the production of brake discs. The reinforcing phase is a SiC foam with an activated surface. The use of ceramic foam simplifies the production process because it does not require expensive mixing of the matrix and the reinforcing phase to ensure the homogeneity of the composite. An addition of 10% SiC (λSiC=100-350 Wm-1K-1) improves the thermal conductivity of cast iron (λCI=50-60 Wm-1K-1). The presence of foam elements homogenously distributed throughout the whole matrix volume reduces the wear of both the composite and the counter-sample. The results of comparative studies of contacts between the cast iron and the composite brake disc showed almost a threefold lower wear of the pad and disc and about a 10°C lower temperature in the pad near the friction zone under the pressure of 1 MPa and at a sliding velocity of 0.5 m/s. The significantly lower wear of the friction elements of the brake system will contribute to a reduction in environmental pollution by wear debris, which is required by European Union directives.

ANALISIS STRUKTUR PADA DISC BRAKE DENGAN VARIASI MATERIAL DAN JUMLAH LUBANG VENTILASI TERHADAP TEMPERATUR DAN TEGANGAN EKUIVALEN

Manny disc brake are produced at conventional machinery workshop. But, the optimum value of disc brake based on heat dissipation, and the safety is unknown. One of the causes of vehicle accidents is the vehicle factor (brake failure). Prolonged and continuous braking on the disc brake can result in fadding. Continuous stress generation can decrease fatigue life. The required material and the right number of holes are needed to solve this problem. The Purpose of this research is to get the optimum temperature and stress value. In this study, simulations were carried out with CAE software on disc brakes with materials Al 7075- T6, SS 304, gray cast iron and the number of ventilation holes 36, 48, 60. The results show that the disc brake with Al 7075-T6 material and 60 ventilaton holes has the best heat dissipation with 38,005ᴼC temperature value. Material gray cast iron with number of ventilation holes 48 produces the lower equivalent stress with 89,272 Mpa. From the research it can be concluded, disc brake with higher density,has higher temperature too. The greater tensile strength of disc brake material, resulting the lower equivalent stress. The gray cast iron material and the number of ventilation holes 48 is the most optimal in temperature absorption, the longest fatigue life, and the highest fatigue safety factor, with a temperature value of 54.99ᴼC, a fatigue life of 100000000 cycles, and an FOS of 3.34.The more number of ventilation holes, has the lower of temperature result but the higher stress concentration.

Structural Performance of Additively Manufactured Cylinder Liner—A Numerical Study

Climate change is exacerbated by vehicle emissions. Furthermore, vehicle pollution contributes to respiratory and cardiopulmonary diseases, as well as lung cancer. This requires a drastic reduction in global greenhouse gas emissions for the automobile industry. To address this issue, researchers are required to reduce friction, which is one of the most important aspects of improving the efficiency of internal combustion engines. One of the most important parts of an engine that contributes to friction is the piston ring cylinder liner (PRCL) coupling. Controlling the linear deformation enhances the performance of the engine and, as a result, contributes positively to its performance. The majority of the tests to study the conformability between cylinder liner and piston were carried out on cylinder liners made of cast iron. It is possible to improve the performance of piston ring cylinder liner couplings by implementing new and advanced manufacturing techniques. In this work, a validated finite element model was used to simulate the performance when advanced manufactured materials were adapted. The deformation of the cylinder liner due to thermal and mechanical loads is simulated with five different additive manufactured materials (Inconel 625, Inconel 718, 17-4PH stainless steel, AlSi10Mg, Ti6Al4V). Simulated roundness and straightness errors, as well as maximum deformation, are compared with conventional grey cast iron liner deformation. Some additive manufactured materials, especially Ti6Al4V, show a significant reduction in deformation compared to grey cast iron, both in bore and circumferential deformation. Results show that Ti6Al4V can reduce maximum liner deformation by 36%. In addition, the roundness improved by 36%. The straightness error when Ti6Al4V was used also improved by 44% on one side, with an average of 20% over the four sides. Numerical results indicate that additive manufactured materials have the potential to reduce friction within the piston liner arrangement of internal combustion engines.

Modal Analysis of an 8/6 Pole Switched Reluctance Motor Core with Different Materials and Assembly Method Using FEA

Vibration causes acoustic nuisance, aggravating fatigue etc. Knowing that resonance is caused by amplified deformation when a structure is excited at natural frequency, modal analysis is important to identify the natural frequency and mode of deformation that may be excited in electrical machine. This study analyzes the natural frequency and mode shape of major components in 120v 4-Phase 8/6 Pole Switched Reluctance Motor. The material selected are materials that are commonly employed for electrical machines components. It was found that gray cast iron core has the lowest natural frequency for each mode from 1 to 3. This is mainly due to its lower elasticity modulus (10 times smaller in comparison to other materials). Solid and slinky rotor has a very low first mode natural frequency at tens of Hz, which is very susceptible to mechanically induced excitation vibration.

Enhancement of Mechanical Properties and Corrosion Resistance of Cast Iron Alloy Using CO2 Laser Surface Treatment

This work aimed to study the effect of laser surface treatment on the mechanical characteristics and corrosion behaviour of grey cast iron type A159. Many technical applications used conventional surface treatment, but laser surface hardening has recently been used to enhance the surface properties of many alloys. The mechanical characteristics, including microstructure, microhardness, and wear resistance of A159 grey cast iron, were studied, in addition to corrosion behaviour. The experimental laser parameters in this work were 0.9, 1.2, and 1.5 KW power with continuous wave carbon dioxide lasers with scanning speeds of 10 and 12 mm/s were used. The results found that phase-transitional alterations in microstructure were influenced by laser therapy. Also, the microhardness increased with increasing power, with the maximum reaching approximately 950 HV while the base metal has an average of approximately 260 HV. Also, we found the power laser increased corrosion resistance by lowering the corrosion rate (CR) from 21.10 for the untreated sample to 1.02 (m.p.y.), additionally, corrosion protection efficiency (CPE) increased to 95.27 percent. On the other hand, the wear test revealed that mass loss decreased as laser surface treatment power increased; it reached 0.19 g for the laser-treated samples, compared to 1.25 g for the base metal after the 50th minute of the wear experiment.

Development and characterization of foundry refractory coating and validation through factorial design of experiment

Foundry Refractory Coatings are used to improve surface finish of grey iron castings and reduces the re-work cost that covers the surface defects. Present research was concentrated on qualitative and quantitative analysis of commercial coatings through X-ray Diffraction and Energy Dispersive Spectroscopy respectively. A number of coating compositions were prepared by means of refractory fillers, binders and particle size as most concern parameter and validated through Design of Experiment. Ultimately, three types of coating formulation were developed by coating constituents and characterized using X-ray Diffraction. Fe2O3 and SiO2 were determined as major phases in all coating samples. Particle size of 75 microns was used for smooth surface finish. Gray iron casting had been produced without disturbing the mechanical properties and graphite distribution. Surface defects were covered by one of the best refractory coating recipe.

A variable amplitude fretting fatigue life estimation technique: Formulation and experimental validation

The aims of the research work summarised in this paper are twofold. The first goal is to make available a large number of new experimental results generated by testing specimens of grey cast iron under both constant and variable amplitude fretting fatigue loading. The second goal is to formulate an advanced fretting fatigue design approach based on the combined use of the Modified Wӧhler Curve Method, the Theory of Critical Distances and the Shear Stress-Maximum Variance Method. The validation exercise based on the experimental results being produced demonstrates that the proposed methodology is a powerful tool suitable for designing mechanical assemblies against fretting fatigue.

Concept of Equivalent Stress Criterion For Predicting Failure of Brittle Materials

Purpose: A paucity of proven failure criteria for brittle engineering materials exists, and this paper intends to present and validate a novel concept of equivalent stress criterion for predicting the failure of brittle isotropic homogeneous materials based on the concept of effective causative failure stress.
 Design/Methodology/Approach: Mathematical modelling is first performed based on strain-state equivalence, followed by conversion to the equivalent causative stress. The model is then validated with experimental and other data and with comparisons to traditional models. The material studied is BS 1452 Grade 250 continuous-cast grey cast iron with a Young’s Modulus of 39 000 MPa and ultimate tensile strength of 290 MPa. The test samples were prepared square in shape 12 mm x 12 mm to enable stresses in two perpendicular directions. Data is generated from uniaxial and bi-axial tests, performed using a standard universal testing machine, INSTRON 880, improvised to enable bi-axial recordings.
 Findings: Results point consistently to higher fidelity and transparency of the new model in representing the state of stress, especially in the second and fourth quadrants of the principal stress diagram, where Rankine’s criterion completely ignores stress differences and Mohr handles shear stresses in a suboptimal fashion. Both the maximum principal stresses and maximum shear stresses predicted by the proposed model are found to be somewhat greater than those from the traditional models, indicating higher accuracy and greater aggressiveness in prediction. The findings have further revealed that shearing effects play a greater role in the failure of engineering brittle materials than traditional failure theories have considered.
 Research Limitation: The study involved improvisation to enable biaxial stress recordings. This process was not perfect, resulting in smaller-than-ideal values of the lateral stresses.
 Practical implication: The study recommended process and equipment development toward perfecting multiaxial tests.
 Social implication: The survey will enrich the literature with pertinent design methodology to help in product design, including social-interest products. 
 Originality / Value: Since truly homogeneous materials are known to withstand very high hydrostatic pressures, direct stresses alone do not constitute valid failure criteria for all loading conditions.