Iron Cylinder Research Articles

Speed Measurement of Rotating Hollow Shafts Using an Eddy Current Sensor

Rotating speed measurements of conductive hollow shafts using a new eddy current sensor are presented in this article. Two serially connected excitation coils are used, which are 180° geometrically shifted relative to each other. The pick-up coils have the same configuration as the excitation coils with a 90° geometrically shifted angle relative to the excitation coils. Parametric analyses of the speed sensor are performed using a novel developed analytical method. Detailed calculations of the sensor are presented using the 3-D time-stepping finite-element method. The performance of the eddy current speed sensor is measured up to 3000 r/min at different excitation frequencies. The rotating shafts are two hollow iron cylinders and three hollow aluminum cylinders with different shell thicknesses. The effects of the electrical conductivity and magnetic permeability of hollow shafts on the speed sensor performance are assessed. The measurement results are compared with the calculations for different shafts. The nonlinearity measured error is 0.15%.

Cold-curing mixtures based on biopolymer lignin complex for casting production in single and small-series conditions

<abstract> <p>This study proves that lignin-based biopolymer materials can be employed as starting materials for the synthesis of novel casting binders that fulfill the current level of characteristics. The optimal concentration of the binder in the mixture was experimentally determined to be 5.8%–6.2%. It has been demonstrated in practice that the employment of ammonium salts as a technical lignosulfonate (TLS) modifier can result in the provision of cold (room temperature) curing of a mixture based on them. It was proposed to use as a technological additive that boosts the strength characteristics of a mixture of substances carboxymethyl cellulose (CMC). In a variety of adhesive materials, it is utilized as an active polymer base. The concentration limits for using CMC in the mixture are set at 0.15%–0.25%. To improve the moldability of the combination, it was suggested that kaolin clay be used as a plasticizing addition. The concentration limits for using a plasticizing additive are set at 3.5%–4.0%. The produced mixture was compared to the analog of the alpha-set method in a comparative analysis. It was discovered that the proposed composition is less expensive, more environmentally friendly, and enables the production of high-quality castings. In terms of physical, mechanical, and technological properties, the created composition of the cold curing mixture is not inferior to analogs from the alpha-set method. For the first time, a biopolymer-based binder system containing technical lignosulfonate with the addition of ammonium sulfate and carboxymethyl cellulose was used in the production of cast iron castings on the case of a cylinder casting weighing 18.3 kg from gray cast iron grade SCh20. Thus, it has been proved possible for the first time to replace phenol-based resin binders with products based on natural polymer combinations. For the first time, a cold-hardening mixture based on technological lignosulfonates has been developed without using hardeners made of very hazardous and cancer-causing hexavalent chromium compounds. But is achieved through a combination of specialized additives, including kaolin clay to ensure the mixture can be manufactured, ammonium sulfate to ensure the mixture cures, and carboxymethyl cellulose to enhance the strength properties of the binder composition. The study's importance stems from the substitution of biopolymer natural materials for costly and environmentally harmful binders based on phenolic resins. This development's execution serves as an illustration of how green technology can be used in the foundry sector. Reducing the amount of resin used in foundry manufacturing and substituting it with biopolymer binders based on technological lignosulfonates results in lower product costs as well as the preservation of the environment. Using lignin products judiciously can reduce environmental harm by using technical lignosulfonates, or compounds based on technical lignin. The combination is concentrated on businesses with single and small-scale manufacturing because it is presumable that this is merely the beginning of the investigation. This study confirms the viability of creating a cold-hardening combination based on technical lignosulfonates in practical applications and supports this with the castings produced, using the creation of a gray cast iron cylinder casting as an example.</p> </abstract>

Numerical optimization of the taper a vertically cast plate

The temperature field of the studied plate was analyzed with different angles of widening in its cross section (in the range from 0° to 4.4°). From the inclined side, the plate was either insulated or uninsulated. Plastizol was used as an insulator. An uninsulated plate has a calculated optimum angular expansion of 3°. A widening of 2° is the minimum angle at which internal defects (e.g. shrinkage voids) begin to disappear. The insulated plate has an optimum angle of 2°. Using numerical calculations, it is possible to predict that after crystallization without insulation, the plate itself with a widening of 3° will have the same internal quality as a widening of 2° with insulation. The knowledge gained from this study can lead to a reduction in the volume of liquid metal used and also to a reduction in machining costs. These research results have already been successfully applied to the design of the technology for casting nodular cast iron cylinder liners.

Effect of Laser Surface Texturing on the Tribological Properties and Scuffing Mechanism of CKS Piston Ring Against Cast Iron Cylinder Liner Under High Intensifying

The objective of this study is to characterize and understand the evolutionary processes that the effect of surface texture has on the tribology properties of the Chrom-Keramik-Schicht (CKS) piston ring/cast iron cylinder liner system under high intensifying. Surface dimple textures with an area density of 3–9% were prepared on the CKS piston ring by YAG laser, and the antifriction and antiscuffing properties were tested on a reciprocating test rig at 200 °C and 80 MPa. The minimum friction coefficient and wear loss were both obtained at the area density of 5%, compared with the untextured cylinder liner–piston ring (CLPR). The friction coefficient decreased by 0.013 to 0.086, and the wear loss for the piston ring and cylinder liner decreased by 41% and 46%, respectively. The sharp decrease of the friction force induced by surface polishing of the cylinder liner is taken as a sign to indicate the cylinder scuffing under starved lubrication. The scuffing time for the piston ring/cylinder liner system reached a maximum value of 18 min at an area density of 3%, which is extended about 41% compared with that of the untextured piston ring. The dimple surface texture on the piston ring could extend the scuffing time by delaying the occurrence of polishing behavior on the surface of cylinder liner. It is found that the retarded surface polishing played a major role for the modification of the antiscuffing property of the friction pairs according to the friction curves and wear morphologies.

Experimental and numerical studies of thermal-structural behavior based on cast iron scaled cylinder head specimen

In order to clarify the thermal deformation and failure mechanism of the nodular cast iron cylinder head of marine diesel engines during long-term service, a high-efficiency thermal cycling experiment was conducted on scaled cylinder head specimen based on the similarity principle, and the thermal cycling load was simulated by flame heating and water spray cooling method. Then the Chaboche combined hardening model considering temperature and cumulative effect was established. The cyclic plastic behavior of the scaled specimen model during non-uniform thermal cycling was verified from transient temperature, cumulative out-of-round deformation and crack failure. Subsequently, the law of cyclic plastic deformation of specimens under thermal cycling was studied. The results showed that with the increase of the cycle number, the plastic strain of the valve bridge region of the scaled specimens accumulated gradually, showing a large amount of permanent strain of the circular hole within a maximum of 20.3 μm out-of-round deformation. The difference between the calculated and tested deformation is 1.9 μm (10.5%), which shows the excellent predictability of the numerical model. The research findings are valuable for predicting and evaluating the thermal-structural behavior of the prototype cylinder head.

Simulated Strains-Based Approach for Explaining Distortion and Residual Stress in Quenched Pure Iron Cylinder

Abstract Distortion and residual stress in steel parts because of heat treatment affect assembled products’ performance and life. A trial-and-error method has been used traditionally to solve problems, which requires a lot of time and cost. In the 1970s, heat treatment simulation was realized based on theoretical studies for predicting temperature, volume fraction of metallic phase, stress, strains, and so on, during the processes. In the early 2000s, an approach was established to explain the origin of distortion and residual stress based on the simulated results, especially various kinds of strains, which is called the simulated strains-based approach by the author. This approach has been made possible by simulation, which has provided results such as the time history of strain distribution. The subject of the residual stress generation mechanism in a quenched pure iron cylinder is taken here to illustrate the advantages of this approach. The classic study of this problem is Rose's illustration using a conceptual diagram of the variation of temperature and stress at the surface and center of the cylinder. In connection with this diagram, thermal shrinkage and elastic deformation, and the relationship between them and stress, are qualitatively explained. However, it is difficult to understand this diagram logically because the meaning of the correction applied to the stresses after the onset of plasticity was not clearly explained. On the other hand, the simulated strains-based approach using changes in distributions of thermal, elastic, plastic, and total strains provided a clear explanation of how the final distribution of the elastic strain, which is corresponded to the residual stress, is generated. Because quenching of steel parts produces additional transformation strain and transformation plastic strain, the quenching of pure iron is an excellent introduction to the application of a simulated strains-based approach.

Impact of Aspect Ratios of Solid Rotor, Large Air Gap Induction Motors on Run-Up Time and Energy Input

This article introduces a unique three-phase induction machine with a large air gap and a copper-coated iron cylinder. The motor is built in an X-ray tube for medical applications where key performance indicators are the start-up time, generated rotor, and total energy during the run-up. The common equivalent circuit for induction motors is utilized to systematically analyze the effect of the rotor protrusion length variation on these key performance indicators by means of three-dimensional (3D)-FEA. However, due to the large air gap and dominating winding head standard evaluation tools, such as the no-load and locked-rotor tests do not provide accurate circuit parameters. Thus, a combined no-load and locked-rotor test evaluation is introduced. Furthermore, to avoid the time and computational effort of time-stepping 3D-FEA, time harmonic and static 3D-FEA is introduced. To validate these simplified 3D-FEA simulations, results are compared with the selected time-stepping 3D-FEA results. Experimental results verify the 3D-FEA results. After establishing a routine to identify accurate equivalent circuit parameters by means of 3D-FEA, the parameters for three different stator lengths each combined with six different rotor lengths are identified. <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V/f</i> -controlled run-up simulations are then conducted to generate the results. Results quantify the tradeoff between start-up time, generated rotor, and total energy depending on the rotor protrusion, e.g., the start-up time is indirectly proportional to the rotor protrusion and directly proportional to the rotor frequency (the relative frequency between stator field and rotor speed). The effect of the rotor temperature, which can reach up to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\sim 390^\circ \,$</tex-math></inline-formula> C, on the results is included.

Tailoring the Hybrid Magnetron Sputtering Process (HiPIMS and dcMS) to Manufacture Ceramic Multilayers: Powering Conditions, Target Materials, and Base Layers.

The mechanical and wear behavior of CrN/CrAlN multilayers were improved by tailoring the experimental conditions of a hybrid magnetron sputtering process based on a high-power impulse (HiPIMS) and two direct current magnetron sputtering (dcMS) power supplies. To this end, the influence of the base layer and of the combination of Cr and CrAl targets, which were switched to the dcMS and HiPIMS power supplies in different configurations, were investigated with respect to the growth of ceramic CrN/CrAlN multilayers onto commercial gas-nitrided diesel piston rings. The microstructure, grain morphology, and mechanical properties were evaluated by field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and instrumented nanoindentation. Bench wear tests simulating the operation of a combustion engine were conducted against a gray cast iron cylinder liner under reciprocating conditions using 0W20 oil as a lubricating agent enriched with Al2O3 particles. The results revealed a significant increase in hardness, resistance to plastic strain, and wear resistance when two CrAl targets were switched to a HiPIMS and a dcMS power supply, and a Cr target was powered by another dcMS power supply. The compressive coating stresses were slightly reduced due to the soft Cr base layer that enabled stress relief within the multilayer. The proposed concept of hybrid magnetron sputtering outperformed the commercial PVD coatings of CrN for diesel piston rings manufactured by cathodic arc evaporation.

An investigation on the friction losses between cylinder liner and piston rings

Historically, the engine crankcase has been made of gray cast iron due to that material's' high machinability, damping ability, thermal conductivity, and sensible cost. Despite these advantages and the long-term use of gray cast iron, the vehicle manufacturers predominately use cast aluminum as material of choice for the engine block due to aluminum’s density being almost a third of that of gray cast iron, and the aluminum engines have the same durability as gray cast iron while weighing considerably less. However, due to the low wear resistance of aluminum, efforts are needed to improve internal working surfaces such as the use of cast iron cylinder liners or the application of a protective coat is applied to the aluminum surface to increase its resistance. The purpose of this study is to examine which ring materials have the lowest friction with the Twin Wire Arc (TWA) aluminum cylinder liner. An Ansys simulation model accomplishes the experimental work. The steel ring material obviously had the lowest friction with twin wire arc spray aluminum cylinder liner as opposite to the cast iron material which was the worst.

ZDDP Tribofilm Formation from a Formulated Oil on Textured Cylinder Liners

Surface texturing can improve lubrication and entrap wear debris but increases the effective roughness of the surfaces, which can induce higher contact pressures. On the one hand, this can be detrimental, but on the other hand, the increase in contact pressure could be used to activate the formation of a ZDDP tribofilm from fully-formulated lubricants. This work investigates the synergistic effect between surface texturing via Maskless Electrochemical Texturing (MECT) and ZDDP additive. The surface texture consisted of an array of annular pockets manufactured on a gray cast iron cylinder liner. These textured surfaces were evaluated by scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX). The results indicated that surface texturing via MECT changes the chemical composition of the surfaces, by inducing a preferential dissolution of the metal matrix. Consequently, it exposed the carbon present in the material. The tribological performance was evaluated by a ring-on-cylinder-liner tribometer in reciprocating sliding under boundary lubrication conditions using both a base oil and a commercial formulated oil containing ZDDP additive. For comparison, a commercially honed liner was also tested. After the tribological tests, the surfaces were evaluated by white light interferometry and SEM/EDX. Although the textured surfaces showed higher friction, they induced more ZDDP-tribofilm formation than conventional cylinder liner finish.

Research on Creep Test of Compacted Graphite Cast Iron and Parameter Identification of Constitutive Model under Wide Range of Temperature and Stress

With the increase in engine power density, the temperature and stress carried by the cylinder head during operation also increase. The thermal engine fatigue life prediction of the cylinder head needs to consider accurate and reasonable creep-constitutive models and parameters. In view of the wide range of temperature and stress working conditions of the compacted graphite cast iron (CGI) cylinder head, the creep test of CGI under the conditions of temperature 450~550 °C and stress 100~300 MPa was carried out, and CGI under the conditions of wide temperature and stress was proposed to characterize a creep-constitutive model for minimum creep rate. Research indicated that under wide temperature and stress conditions, CGI was more prone to creep damage than under low load, and creep deformation was dominated by grain boundary sliding (GBS), intragranular dislocation glide (IDG), and dislocation climb (IDC). With the deformation mechanism-based true stress (DMTS) creep model, combined with the multiobjective optimization method, a creep-constitutive model of CGI was constructed, and 73% of the predicted values of the model were within twice the error range. Compared with the linear regression method, the multiobjective optimization method could still fit the accurate model parameters in the case of small samples.

Evolution of residual stress through the processing stages in manufacturing of bore-chilled sand-cast aluminum engine blocks with pressed-in iron liners

To minimize the carbon footprint of the transportation industry, manufacturers and engineers are continuously trying to improve the efficiency of the combustion engine. However, due to the presence of iron cylinder liners in the engine block, high tensile residual stresses are generated during the manufacturing process which leads to a large reduction of the alloy’s useable strength. Thus, the present study utilized neutron diffraction to study, for the first time, the evolution of residual stress of sand-cast aluminum engine blocks that have eliminated the iron cylinder liners from the casting process and mechanically inserted them after heat treatment and machining operations. Moreover, this study also examined the effects that cylinder bore chills have on the resulting residual stress profiles. The replacement of the iron liners shifted the stress mode from purely tension to purely compression until the bore chills were removed. Following the removal of the bore chills, the maximum tensile stress at the top of the cylinder bridge was ~ 70% lower than the engine’s predecessor which was produced with iron liners. Moreover, in the production-ready state (i.e., T7 heat treated and press-fit liners inserted), the stress mode maintains the partially compressive nature, thereby lowering the material’s susceptibility to crack growth and propagation.Graphical Abstract

Ultrasonic flaw detection spectrogram characterization of vermicular graphite cast iron engine cylinder head

The defects formed in the manufacture of the vermicular graphite cast iron engine cylinder head seriously affect the operation of the engine, which is necessary to detect. Ultrasonic testing is a non-destructive testing method that has the advantages of quick response, high resolution, and high security. In this paper, various types of specimens are prepared corresponding to different types of actual defects in the vermicular iron cylinder head. An ultrasonic A-scan system was built to test the specimens. The short-time Fourier transform, the continuous wavelet transform, the empirical wavelet transform, and the empirical modal decomposition were adopted to transform the signals into spectrograms which were further analyzed to reveal the inherent features of defects. The results show that the short-time Fourier transform can be used to distinguish all the common defects comparing to other methods. Comparing to the time-domain waveforms, the transformed spectrograms provide clear time-frequency distribution and highlight the inherent characteristics of the signal.

Intelligent recognition of defects in vermicular graphite cast iron engine cylinder head by ultrasonic testing

To detect and intelligently identify the defects of the vermicular cast iron cylinder head, defective casting samples were made corresponding to each type of the actual defects. We setup the ultrasonic testing system to examine the defective samples. The detected defect signals were processed to obtain the characteristic spectrograms of the defects, which were further sorted and classified into a sample database. An algorithm based on a convolutional neural network was proposed to identify the defects intelligently. A convolutional neural network model was established. The network structure and parameters were optimized. It shows that a neural network with 3×3 convolution kernel dimension, 3 convolution layers, 20 convolution kernels in each layer and a learning rate of 0.0005 can effectively identify the spectrograms of the defects. The results show that the identification accuracy of the proposed algorithm is 97.14%. The model meets the practical requirements of cylinder head defect detection. The detection efficiency has improved significantly.

Investigation of the immersion resistance of the HRS-WC mixtures with applying static loading

The inclusion of rainwater often compounds the damage to the road before reaching the plan life through the surface and shoulders of roads. This can lead to the release of aggregates and exfoliation of asphalt on the surface layer. The study aims to determine the level of road durability against the Marshall, volumetric, and durability properties of the HRS-WC mixture. The study used various static loading 100 Kpa, 150 Kpa, and 200 Kpa with immersion. In the immersion method, there are two differences, namely, immersion with and immersion without loading. The test objects’ loading using a simple and economical test tool utilizes the beams and iron cylinders obtained from the laboratory, testing using Marshall Test. The results of the analysis obtained the durability of unloading soaked value higher than the load. The analysis results showed that the durability of the mixture was soaked seven days with a load of 100 KPa was 77.40%, for 150 Kpa amounted to 52.02%, and for 200 KPa, which is 47.67%. Analysis results showed a 7-day immersion value with a cumulative load of 68.38%, while analysis results showed a seven day immersion value with periodic loading of 75.43%.

Analysis of Weight loss in Reciprocating Wear Test of Cylinder Liner and Piston Ring Coated with Molybdenum

In this study, piston rings (PR) were coated with Molybdenum (Mo) powder High Velocity Oxygen Fuel (HVOF) coating method. In addition, the wear behavior of the Mo coated PR and the cast iron (CI) cylinder liner (CL) were examined. The parameters of load, temperature and revolution wear were optimized according to L27 array of Taguchi method in order to obtain minimum wear loss in wear tests. It has been determined from the experimental results that the most effective parameter for the minimum wear loss of both the PR and the CL was the load. Mathematical models were obtained using regression analysis. The results of the verification test of the optimization method and the experimental results were very close to each other. Wear maps have been created for the PR and CL. The analysis of the wear surfaces showed that the abrasive wear mechanism was dominant.

Study on interaction mechanism of different atomic ratio of neodymium, arsenic and iron

In this study, neodymium and arsenic were sealed into industrial pure iron cylinders at a temperature of 1223 K for 50 h. The interaction mechanism of the Nd–Fe–As system at various atomic ratios was investigated by optical microscopy, X-ray diffractometry, and scanning electron microscopy. Binary compounds Fe12As5, NdAs, Fe2As, and Fe17Nd2 were the main products formed, with traces of NdFeAs compounds. In addition, at high temperatures, As content affected the diffusion of Fe atoms; the diffusion of Fe increased with an increase in the atomic ratio. Furthermore, the diffusion ability of Nd was weaker than that of As. The major diffusion mechanism of Nd was through the Fe atomic vacancy mechanism. As mainly bind to Fe to form Fe and As compounds. The formation of ternary compounds was confirmed by laboratory experiments and mismatch calculations.

Quantitative models for microstructure and thermal conductivity of vermicular graphite cast iron cylinder block based on cooling rate

The relationships of cooling rate with microstructure and thermal conductivity of vermicular graphite cast iron (VGI) cylinder block were studied, which are important for design and optimization of the casting process of VGI cylinder blocks. Cooling rates at different positions in the cylinder block were calculated based on the cooling curves recorded with a solidification simulation software. The metallographic structure and thermal conductivity were observed and measured using optical microscopy (OM), scanning electrical microscopy (SEM) and laser flash diffusivity apparatus, respectively. The effects of the cooling rate on the vermicularity, total and average areas of all graphite particles, and the pearlite fraction in the VGI cylinder block were investigated. It is found that the vermicularity changes in parabola trend with the increase of cooling rate. The total area of graphite particles and the cooling rate at eutectoid stage can be used to predict pearlite fraction well. Moreover, it is found that the thermal conductivity at room temperature is determined by the average area of graphite particles and pearlite fraction when the range of vermicularity is from 80% to 93%. Finally, the quantitative models are established to calculate the vermicularity, pearlite fraction, and thermal conductivity of the VGI cylinder block.

GROUTED SLEEVE CONNECTION FOR PRECAST CONCRETE MEMBERS

Precast concrete structures have gained preference in the modern construction industry because of the multiple advantages they offer. The connection of precast members is an important aspect to consider in the design of structures with precast components. Grouted Sleeve connection, one of the famous connector types, is made of the trio of reinforced bars, high strength grouting materials and a ductile iron cylinder. This article compares the finding of recent experimental research findings on grouted sleeve connection and establishes the relationship between the three components of the connector to enhance the performance of the splicing agent. It is found that the tensile performance of the connector increases with the embedded length of the bar for a normal sleeve. An effective embedded length set between 6 and 8 times the diameter of the bar will maximize the tensile performance of the connector. The increase in diameter of the sleeve cylinder, the compressive strength of the grout and the length of the bar embedded and its surface will affect the bond performance and the mode of failure under tensile load.

Residual stress, microstructure, and mechanical properties analysis of HPDC aluminum engine block with cast-in iron liners

During the manufacturing of cast aluminum (Al) engine blocks with iron (Fe) cylinder liners, the mismatch of thermal expansion/contraction coefficients between the Al cylinder wall and the Fe liners results in the development of high residual strains/stresses. This evolution of residual stress can surpass the strength of the currently used alloys and can lead to the premature failure of the engine block. Thus, improving the mechanical properties of the engine block alloys reduces the number of failures and allows automotive manufacturers to increase the operating pressures and, therefore, efficiency. High-pressure die casting (HPDC) has been shown to provide increased cooling rates in the casting as compared to sand casting, and therefore manufacturers commonly use this method for improving not just the efficiency of the high-volume production, but also mechanical properties of the cast components. Hence, investigating the impacts of the HPDC process on the evolution of residual stress in engine blocks with Fe liners and, consequently, their durability is of great importance. The present study includes a microstructural, mechanical property, and residual strain analysis on an inline-4 HPDC Al engine block with cast-in Fe liners. The results indicate that the yield and tensile strength at the top of the cylinder were ∼15 % and ∼8 % greater than the bottom, respectively. This trend was primarily attributed to the higher cooling rate experienced by the top region. Moreover, the top and bottom of the Fe liner experienced 450 MPa of compressive residual stress in the axial direction, which is counterbalanced by tensile stresses in the Al cylinder bridge (CB), which reaches approximately 70 % of the alloy’s yield strength. The findings of this study provide automotive industries with important insights on the combined impacts of the HPDC process and cast-in Fe liner on the as-manufactured properties of engine blocks and will assist them in developing the next generation of engine blocks.