Cast Iron Alloys Research Articles

Reaction Behavior at the Contact Interfaces between High-Manganese Cast Steel or High-Manganese Spheroidal Graphite Cast Iron and Molten Aluminum Alloys

Reaction Behavior at the Contact Interfaces between High-Manganese Cast Steel or High-Manganese Spheroidal Graphite Cast Iron and Molten Aluminum Alloys

Exploring residual stress analysis in the machining of hypoeutectic high chromium white cast iron alloys through the hole-drilling method

Abstract High chromium white cast irons (HCWCIs), ASTM A352, Type A and Class III, i.e., 25%Cr iron in as-cast condition consists of proeutectic austenite (γ-Fe), transformed martensite (α-Fe) and discontinuous Cr-rich, i.e., M7C3/ (Cr, Fe)7C3 type of carbides, which are hard and brittle in nature. Fully annealed thermal treatment was performed to improve iron’s machinability leading to fully pearlitic matrix with minor retained γ-Fe content. Eutectic (Cr, Fe)7C3 type of carbides are not affected by heat treatment processes. Resulting from corresponding manufacturing process, the magnitude and distribution of residual stresses (RSs) in as-cast and after machining were measured using hole-drilling method (HDM), as they are known to be harmful to corrosion and fatigue resistance. Furthermore, general metallurgical material characterisation was performed in as-cast and heat-treated conditions. As a result, this study revealed hardness variation, 547 and 555BHN in as-cast as compared to 327BHN in heat-treated condition. Furnace and actual cast component chemical analysis revealed a slight variation, especially between carbon (C) and chromium (Cr). Furthermore, eutectic type of carbides and precipitated secondary, i.e., (Cr, Fe)23C6 type of carbides within fully pearlitic matrix with minor amounts of retained γ-Fe were detected within the dominant matrix, i.e., pearlitic matrix in as-annealed condition. Detected magnitude and distributions of RSs on heat-treated sample resulted in higher tensile stresses in the surface and compressive in the interior as compared to sample in as-cast condition. Thus, this study was successfully in measuring RSs in as-cast and upon machining of hypoeutectic irons of HCWCI alloys using HDM.

Effect of Cr:C ratio on open three-body wear resistance of squeeze cast high chromium cast iron

A series of high chromium white cast iron (HCCI) alloys with varying Cr:C ratios were designed and fabricated through the squeeze casting process. This study investigates the effect of the Cr:C ratio on the mechanical properties, microstructure, phase diagram, and both low-stress and high-stress abrasion performance of HCCIs. Alloys with a very high Cr:C ratio exhibited better impact toughness but poorer hardness. Scanning electron microscopy (SEM) and phase diagram calculations elucidated the influence of the Cr:C ratio on microstructure, carbide volume fraction, and carbide type. Abrasion resistance was evaluated using impact abrasive wear (high-stress) and rubber-wheel (low-stress) abrasion on quartzite in open three-body wear. Comprehensive assessments under impact abrasive wear and rubber-wheel abrasive wear conditions suggest that the alloy achieves optimal abrasion resistance with a Cr:C ratio ranging from 8 to 11. Post-wear analysis reveals that surface damage varies between high-stress and low-stress conditions. The microstructure of squeeze HCCIs is significantly influenced by the Cr:C ratio, resulting in diverse operative wear mechanisms, including micro-cutting and micro-fracture. Successful adjustment of the Cr:C ratio led to the attainment of a nearly eutectic HCCIs composition suitable for squeeze casting.

Classification of Cast Iron Alloys through Convolutional Neural Networks Applied on Optical Microscopy Images

Classification of cast iron alloys based on graphite morphology plays a crucial role in materials science and engineering. Traditionally, this classification has relied on visual analysis, a method that is not only time‐consuming but also suffers from subjectivity, leading to inconsistencies. This study introduces a novel approach utilizing convolutional neural networks—MobileNet for image classification and U‐Net for semantic segmentation—to automate the classification process of cast iron alloys. A significant challenge in this domain is the limited availability of diverse and comprehensive datasets necessary for training effective machine learning models. This is addressed by generating a synthetic dataset, creating a rich collection of 2400 pure and 1500 mixed images based on the ISO 945‐1:2019 standard. This ensures a robust training process, enhancing the model's ability to generalize across various morphologies of graphite particles. The findings showcase a remarkable accuracy in classifying cast iron alloys (achieving an overall accuracy of 98.9 ± 0.4%—and exceeding 97% for all six classes—for classification of pure images and ranging between 84% and 93% for semantic segmentation of mixed images) and also demonstrate the model's ability to consistently identify and graphite morphology with a level of precision and speed unattainable through manual methods.

Casting Production in Poland Versus European Trends in 21st Century

This article presents changes of the total casting production volumes and of the production of castings made from basic casting alloys in Poland, in Europe and worldwide in years 2001–2021. Analogous casting production parameters were compared for Poland, Europe and countries being the leading European and global manufacturers in years 2001, 2011 and 2021. The leading casting manufacturers in Europe (with the manufacturing volume exceeding 1 million tons in the mentioned years) include Germany, Italy, the Ukraine, France and Spain. For years, the largest casting manufacturer worldwide has been China. In 2001–2021, global casting production increased from ca. 68 million tons to ca. 97 million tons (i.e. by ca. 42%), whereas the European one decreased from ca. 17 million tons to ca. 12 million tons (i.e. by close to 30%). In the analyzed period, the Polish production volume grew from ca. 0.75 million tons to ca. 0.88 million tons (i.e. by ca. 17%). The presented data reveal the decreasing importance of gray cast iron and cast steel and the increasing one of ductile cast iron and aluminum alloys. However, the Polish average annual growth rate for aluminum alloy casting production was 10.3%, whereas the global one was 3% and the European one 0.7%.

Дослідження впливу параметрів процесу хонінгування силікатними брусками на якість обробленої поверхні

Numerous studies have shown that the kinematics of the honing process, which determines the trajectory of the cutting grain during machining, has a major impact on the parameters of macro- and microrelief. The complex working movement during honing of holes creates favourable conditions for the fuller use of the cutting capacity of the bars and uniform wear of the tool, which positively affects the machining performance and accuracy of the geometric shape of the surface. It is shown that, in this regard, there is a need to investigate the influence of the parameters of the honing process with silicate bars on the quality of the machined surface. The paper presents the results of a study of the effect of the contact pressure of the bars and the axial and circumferential speeds on the quality of the treated surface. The study was performed on a vertical single-spindle honing machine. The samples used were cylinder liners of car engines made of grey alloy cast iron. The evaluation was based on the roughness of the machined surface and the mass removal of metal during machining. The best performance was achieved by those bars that resulted in the lowest roughness of the samples. It was found that with an increase in the circumferential speed, the surface quality improves, and with an increase in the axial speed, it deteriorates after processing with diamond, abrasive and silicate stones. With an increase in the contact pressure of the bars, the surface quality deteriorates after machining with diamond bars and improves after machining with abrasive and silicate bars. It has been proven that the high surface quality after treatment with silicate blocks is due to the formation of amorphous silica during honing, which, under the influence of abrasive grains, falls into the cavities of the treated surface and adheres to the surface, thus saturating the treated surface with silicon oxide. It has been established that with an increase in the axial speed of the bars, metal removal increases, and with an increase in the circumferential speed, it decreases after machining with diamond, abrasive and silicate bars. With an increase in the contact pressure of the stones, metal removal increases after machining with diamond stones and gradually decreases after honing with abrasive and silicate stones. It was found that the metal removal after machining with silicate stones is 2 times less than after honing with diamond stones. It is proposed to set the allowance for finishing honing with silicate stones for cylinder liners made of alloy cast iron (HB 240) within 0.01-0.02 mm.

Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry. To study the mechanical behavior of a typical ductile cast iron (GJS-450) with nodular graphite, uni-axial quasi-static and dynamic tensile tests at strain rates of 10−4, 1, 10, 100, and 250 s−1 were carried out. In order to investigate the influence of stress state on the deformation and fracture parameters, specimens with various geometries were used in the experiments. Stress strain curves and fracture strains of the GJS-450 alloy in the strain rate range of 10−4 to 250 s−1 were obtained. A strain rate-dependent plastic flow model was proposed to describe the mechanical behavior in the corresponding strain-rate range. The available damage model was extended to take the strain rate into account and calibrated based on the analysis of local fracture strains. Simulations with the proposed plastic flow model and the damage model were conducted to observe the deformation and fracture process. The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys. The predictions with the proposed plastic flow and damage models at various strain rates agree well with the experimental results, which illustrates that the rate-dependent plastic flow and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates. The proposed plastic flow and damage models can be used to describe the deformation and fracture analysis of materials with similar properties.

Design and Manufacturing of Air Conditioning Coil

This paper consists of the detail design process of a cooling coil which is used in Evaporator of VARC System for given cooling load. The process consists of designing a part using the calculation and various other parameters. The stability of long-term materials is becoming increasingly important as the demand for air conditioning systems in commercial and residential applications grows. Because of temperature variations and heat flow, materials in air conditioning systems can fail, reducing the cooling effect of the system. Low thermal transitions through the coil's material cause a significant amount of heat to be wasted in the evaporator coil, which lowers the system's overall efficiency. This paper outlines the methodology used to choose the right material for the evaporator coil in an air conditioning system using the CES Granta design software. Based on design and functional requirements, nickel-chromium alloys, pure titanium, copper, low alloy steel, cast iron, and pure titanium are the candidates that made the shortlist for evaporator coils. The best candidates are low alloy steel, titanium, and stainless steel.

Effect of salt bath temperature on microstructure and mechanical properties of an austempered alloyed cast iron

Effect of salt bath temperature on microstructure and mechanical properties of an austempered alloyed cast iron

Erosion behavior of various high chromium cast iron alloys exposed to gas-blast stream of ferric oxide particles

Depositing hardfacing material onto a surface with the welding method is a common way of protecting surfaces against wear damage. In this study, five high chromium hardfacing alloys were used to prepare samples for the gas blasting erosion test. Erodent particles were ferric oxide specks with a hardness of 657 HV and an average size of 260 μm. Impinging stream eroded the surface of samples with the gas flow of 100 m/s at an angle of 30° while the particle feed was increased from 140 to 630 g. The results indicated that erosion resistance is dominated by bulk hardness of hardfaced alloys. In addition, the erosion rate for a sample containing Mo, Nb, V, and W was the lowest since it had the highest bulk hardness among all other samples.

ANALISA KEKUATAN TARIK PADA HASIL PROSES PENGECORAN NOZZLE UNTUK BRAKE COUPLING MENGGUNAKAN METODE CETAKAN PASIR JOLT SQUEEZE

Sand casting is one of the metal casting methods that has been developed and is still being improved. Sand casting is a type of metal casting that use sand molds. There are several ways to make sand casting, However, this study use the jolt squeeze technique to create complex product forms such as the nozzle component of the air brake coupling. FCD 500 nodular cast iron alloy castings are used in the production of brake coupling nozzles. The goal of this research focuses on the metal casting technique for nozzle products for brake coupling, and then continue with the tensile testing procedure. Tensile testing utilizing JIS Z 2201 standards with two sampels with different diameters, specifically 12,46 mm and 12,79 mm, and material types FCD 500-1 and FCD 500-2. The research results show the sequence of the nozzle metal casting process for brake couplings, through the stages of designing, constructing models and cores, making molds, melting, pouring, fettling and finishing, and quality control. Tensile stress values of 525 N/mm2 and 546,189 N/mm2 were obtained for each FCD 500-1 and FCD 500-2 sampels, with force loads of 64000 N and 70130,66 N, respectively.

Effects of niobium and molybdenum addition on microstructural characteristics and wear properties of 14 wt%Cr white cast irons

White cast iron (WCIs) alloys were developed by adding Nb, Mo, and a combination of both (∼3 wt% Nb, ∼3 wt% Mo, ∼1 wt% Mo-2 wt% Nb) through melting and casting. The objective was to analyze the microstructural characteristics of the alloys, as well as the impact of reinforcing carbides on their mechanical and tribological properties. The alloy containing the highest percentage of niobium exhibited a refined microstructure, tending towards a eutectic structure, unlike the Mo-containing materials with totally hypoeutectic microstructures. The microstructural characteristics of the alloys and morphology of niobium carbides, as well as the percentage of M7C3 eutectic carbides produced were affected by the varying percentages of Nb and the Mo–Nb combination. Moreover, thermodynamic simulations revealed that the NbC carbide precipitated before the M7C3 eutectic carbides, austenite dendrites, and the MC (composed mainly of Nb containing bound Mo) carbide resulting from the Mo–Nb combination. The alloys containing Mo had similar bulk hardness values, while the alloy with the highest percentage of Nb showed a higher bulk hardness value. This was attributed to the effect of Nb on microstructure refinement and on the production of M7C3 eutectic carbides from the alloy. Although there were different reinforcing carbides (NbC, MC and M2C), the differences in microstructural characteristics had no noticeable influence on the Charpy impact energy. Micro-scale abrasive wear test (conducted with SiC abrasive slurry) demonstrated that the reinforcing carbides MC and mainly NbC had a beneficial effect in blocking and preventing the progression of continuous micro-cuttings and formation of grooves. The M7C3 and M2C carbides were less effective at protecting the matrix against the high-hardness SiC abrasive.

Research on thermal deformation of cylinder bore with orthogonal experiment method of aluminum alloy cylinder block in diesel engine

Using aluminum alloy materials provides an efficient and direct method for achieving engine weight reduction. In this study, a thermo-mechanical coupling simulation model of the diesel engine was established to investigate the deformation of cylinder bores in both cast iron and aluminum alloy cylinder blocks. The reliability of the simulation model is validated by the temperature field test of the cast iron cylinder. Four evaluation indexes, namely average roundness, cylindricity, coaxiality, and light leakage, were used to assess the deformation of the cylinder bore. The results indicate that the temperature is the primary factor contributing to the deformation in both cast iron and aluminum alloy cylinder bores. Under thermo-assembly condition, the average roundness, cylindricity, coaxiality, and light leakage rate of aluminum alloy cylinder bore were observed to be higher by 36.71 %, 12.69 %, 14.77 %, and 18.85 %, respectively, compared to those of cast iron cylinder bore. To decrease the deformation of the cylinder bore, the orthogonal experiment method was used to study the three factors affecting the heat dissipation of the water jacket. It was discovered that extending the water jacket extends upward was the most effective way to reduce the temperature of the cylinder block. By selecting the optimal combination scheme for simulation calculations, an optimized cylinder temperature of 162 °C, with the maximum deformation of the cylinder bore decreasing by 13.64 %. Additionally, the average roundness, cylindricity, coaxiality, and light leakage rate of the cylinder bore showed reductions of 17.48 %, 21.8 %, 23.00 %, and 14.10 %, respectively, when compared to the original aluminum alloy cylinder block.

Study of Stir Casting and Microstructure of Al-B<sub>4</sub>C MMCs

The economic, performance, and environmental advantages of accepting Aluminium (Al) metal matrix composites (MMCs) over steel, cast iron and light alloys are driving forces behind their utilisation. The transportation industry benefits from reduced noise, reduced emissions from airplanes, and reduced fuel use. Continuous research in this field has resulted in improved manufacturing procedures, allowing these Aluminium based composite materials to be used in aerospace industry, marine and vehicle applications rather than most monolithic materials. The industrial sector is rapidly developing, which increases demand for innovative materials. In cases where 'wear' is a critical issue, conservative materials and alloys have limits in reaching the appropriate hard characteristic. Al-MMCs are composite materials that contain Al or an alloy of Al. It acts as the matrix and the reinforcement distributed across the matrix. Common reinforcing materials include fibres, whiskers, and particles. Because of its enhanced density, great hardness, and thermal stability, ceramic reinforcement is the most used. However, they have limits such as less ability to wet and compatibility with the Al matrix. The major production processes for Al-MMCs are powder and liquid metallurgy. All the manufacturing procedures outlined are appropriate, however casting with stir to mix is cost-effective, particularly for big production runs. The distribution of reinforcement evenly to generate a flaw-free structure at micro level and hence raise the resistance to hard behaviour is a critical difficulty in the synthesis of MMCs of Al. Al-MMCs with particle reinforcement have increased mechanical characteristics and wear resistance. Furthermore, the production of MMCs reinforced with particulates is an exciting task, with questions arising due to ductility decline as the weight percent of ceramic particulate reinforcement is increased, gravity segregation due to denser particulates, and oxidation due to the use of Al alloy, which is very susceptible to oxidation. In the present study Al6061-3% B4C MMCs have been developed by stir casting technique. Al6061 is an extruded raw material as purchased from the supplier (and not an ingot) used before remelting and manufacturing the MMCs. The microstructure of the manufactured Al-alloy and Al-MMCs are evaluated. It is observed that stir casting is a suitable method to manufacture Al-MMCs.

FKM-guideline “Analytical strength Assessment” – Background and current developments

The FKM-Guideline “Analytical Strength Assessment” contains an algorithm for both static and the fatigue strength assessment of components made of steel, cast iron, and aluminium alloys. Designed to be advantageous for industrial applications, this guideline expresses the design stress using a straightforward linear-elastic material behaviour.Starting with the material strength properties specified in technical standards, the relevant component properties for both static and fatigue strengths can be determined by considering all influencing factors. The safety level required for assessment can be adjusted using experience-based safety factors. The outcomes of the analytical strength assessment provide a measure of the degree of utilisation.While the FKM-Guideline has been successfully applied since 1994, continuous further development is necessary to ensure it remains at the forefront of industry standards. Key development areas include the improvement of the critical strain curve, introduction of a coordinate-invariant fatigue strength assessment procedure, conducting investigations on the accuracy of the calculation according to the FKM-Guideline as a precondition for the development of a probabilistic safety concept, and extension of the FKM-Guideline to additional material groups such as high-strength steel.

Microstructure and Properties Variation of High-Performance Grey Cast Iron via Small Boron Additions

A study was undertaken to investigate the effects of small boron additions on the solidification and microstructure of hypo-eutectic alloyed grey cast iron. The characteristic temperatures upon crystallisation of the treated metal melt were recorded, specifically those concerning small boron addition by using thermal analysis with the ATAS system. Additionally, a standardised wedge test was set to observe any changes in chill performance. The microstructures of thermal analysis samples were analysed using a light optical microscope (LOM) and field emission scanning electron microscopy (FE-SEM) equipped with energy dispersive spectroscopy (EDS), which reveal variations in graphite count number with the addition of boron within observed random and undercooled flake graphite. The effect of boron was estimated by the classical analytical and statistical approach. The solidification behaviour under equilibrium conditions was predicted by a thermodynamic approach using Thermo-Calc. Based on all gathered data, a response model was set with boron for given melt quality and melt treatment using the experimentally determined data. The study reveals that boron as a ferrite and carbide-promoting element under the experimental set shows weak nucleation potential in synergy with other heterogenic nuclei at increased solidification rates, but no considerable changes were observed by the TA samples solidified at slower cooling rates, indicating the loss of the overall inoculation effect. The potential presence of boron nitride as an inoculator for graphite precipitation for a given melt composition and melt treatment was not confirmed in this study. It seems that boron at increased solidification rates can contribute to overall inoculation, but at slower cooling rates these effects are gradually lost. In the last solidification range, an increased boron content could have a carbide forming nature, as is usually expected. The study suggests that boron in traces could affect the microstructure and properties of hypo-eutectic alloyed grey cast iron.

Tool life assessment of high strength cast iron alloys in dry face milling operations

The advancement in cast iron alloy properties has led to more efficient materials, especially in the automotive industry. However, this progress has also increased the demand for more durable tools with greater resistance to cutting operations. Conducting an in-depth investigation into the impact of these materials on tool lifespan is crucial, as it directly affects productivity. The main objective of this study was to analyze the lifespan of uncoated cemented carbide tools during milling operations using four high-strength cast iron alloys under various dry cutting conditions. A full factorial Design of Experiment (DoE) (23) was employed. The input variables included cutting speed (vc) of 230 and 350 m/min, tool feed (fz) of 0.1 and 0.2 mm/tooth, and materials, namely cast irons (FC 250, FC 300(Mo), FC300(Mo+RG), and FV 450). Additionally, material tests were conducted on billets without holes to simulate mild cutting conditions and with holes for more severe machining conditions. The established machining operation was face milling without cutting fluid, with the axial depth of cut (ap) and radial depth of cut (ae) maintained constant at 1 mm and 60 mm, respectively. The results showed that FV 450 had the shortest tool life, as expected for the hardest and resistant material, with a maximum lifetime difference of 83 % less when compared to FC 250, the softest one that had the longest tool lifespan. The introduction of holes also significantly reduced the overall tool life by about 57 %. The findings highlight the importance of factors such as cutting speed, feed per tooth, material composition, impact, and workpiece surface quality, which significantly influence tool performance.

Thermal Analysis of Different Piston Head Profiles by using FEM

The objective of this research work is to optimize the stress variations at the top of the piston in real engine conditions. During this pressure analysis on the examined surface of the piston, the thermal behavior is examined. The operating gas pressure, temperature and piston material functions are used as investigation functions. The analyzes carried out showed that the upper part of the piston could be damaged or broken due to the temperature caused by the working conditions, as the replacement of damaged or non-functioning parts is very expensive and usually difficult to obtain. Concave and convex piston profile designed in Solid Work 2023, used to design the piston geometry and for FEM analysis to optimize the thermal behavior of the used ANSYS R23.0 piston. Aluminum alloy and gray cast iron material for piston construction. Stress and displacement are analyzed for the piston by applying pressure to it in the structural analysis. By observing the results of the analysis, we can decide whether the piston we are designing is safe or not under the applied load conditions. Heat flow and thermal temperature distribution are analyzed using piston surface temperatures in thermal analysis.

Tribological Properties of Several Surface-Modified Piston Rings Under Extreme Conditions

Abstract This article explores the performance of different commercial piston rings when matched with a boron-phosphorus (BP) alloy cast iron cylinder liner, specifically in high-power density diesel engines. The focus is on the friction, wear, and scuffing characteristics. An interrupted wear test was conducted under lean oil conditions to study the scuffing behavior of plated Cr-diamonds coating (GDC) and diamond-like carbon coating (DLC). The findings reveal that DLC coatings exhibit superior tribological properties, displaying low friction coefficients and wear loss at temperatures of 150 °C and 240 °C. In contrast, GDC coatings demonstrate relatively poor performance. Additionally, the DLC coating demonstrates excellent scuffing resistance, as no material transfer was observed for up to 77 min, even without lubrication. The interrupted scuffing test reveals that the scuffing process undergoes a stable wear stage, followed by a sudden drop and subsequent increase in friction force, ultimately resulting in scuffing when the BP cylinder is paired with GDC. On the other hand, although the frictional force of DLC initially increases after a brief decline, no significant adhesive wear is observed. This can be attributed to the formation of a tribo-chemical layer of carbides, which effectively prevents scuffing. In comparison to traditional methods of postwear morphology and analysis, our proposed interrupted scuffing tests offer enhanced capabilities for evaluating the wear condition of friction pairs at various time intervals during the oil depletion process. This novel approach introduces a new paradigm for investigating wear patterns in different friction pairs.

The damage mechanism of tension-tension fatigue interaction with creep damage of the compacted graphite cast iron alloy at high temperatures

The tension-tension fatigue test of the compacted graphite cast iron (CGI) alloy was carried out by RDL100 universal testing at 500 °C and 550 °C, respectively. A tension-tension trapezoidal load is applied to the CGI specimen. Because of the time-dependent deformation at elevated temperatures, the stress–strain curve presents hysteresis loops, and the area of the hysteresis loop increases gradually with continuous cyclic loading and sustained loading times. Intergranular and transgranular cracks in the microstructure accelerate the CGI alloy fracture failure. The fatigue life is sensitive to the short loading time and decreases with the sustained loading time exponentially under the tension-tension fatigue condition. The short holding time has a great influence on the fatigue life of CGI. The fatigue behavior of CGI alloys and the influence of holding time on the fatigue life can be characterized by y = aexp(bx) (a and b are constants, can be fitted through the test data). In addition, the fatigue life of CGI alloy can be predicted by the ductility depletion method. But the equivalent stress amplitude needs to be modified to eliminate the effects of oxidation damage.