Cast Iron Steel Research Articles

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.

Corrosion performance of 316 stainless steel and nodular cast iron 600-3 in molten Ca(NO3)2-NaNO3-KNO3 salt

The corrosion effect of Ca(NO3)2-NaNO3-KNO3 on 316 stainless steel (316SS) and nodular cast iron 600-3 (QT-600-3) at 520 °C was studied by static corrosion method in argon. After corrosion for 100 h, it was found that there were oxides on the corroded surfaces of the two alloys in XRD spectra. The oxide on the surface of 316SS alloy after corrosion was very thin, and the thickness of Cr depleted layer on the surface of corroded 316SS was only 0.4 μm. On the other hand, a loose oxide layer with a thickness of about 42 μm was formed on the surface of QT-600-3 after corrosion, and its main components were Fe2O3 and Fe3O4. The corrosion of Ca(NO3)2-NaNO3-KNO3 salt on QT-600-3 is much greater than that on 316SS. The fundamental reason for the different corrosion performance of the two materials was the different oxide structures formed on the surface of the two alloy materials. The results may be helpful to the selection of structural materials when Ca(NO3)2-NaNO3-KNO3 salt is used as the heat storage medium.

Dry sliding, slurry abrasion and cavitation erosion of composite layers reinforced by TiC fabricated in situ in cast steel and gray cast iron

To improve the wear resistance of low-carbon steel and gray cast iron, TiC/Fe-type composite layers were fabricated using reactive casting coatings. The in situ synthesis reaction of titanium carbide (TiC) was initiated by the high temperature of the liquid alloy (SHS – self-propagating high-temperature synthesis). The structure, microstructure, hardness, and wear properties of the composite layers were investigated. Wear examinations were carried out in various environments: dry sliding, slurry abrasion, and cavitation erosion in slurry. An observation of the microstructure revealed the presence of TiC particles that were well-bonded with both types of matrices. The mechanical properties showed an almost three-fold increase in the hardness within the area of the composite layer as compared to the base alloy (1000HV1). These results were reflected in a slurry abrasion test that indicated less than half of the weight loss as compared to the monolithic matrix of the composite castings. The cavitation erosion wear mechanism of the composite layers was examined for the first time taking the surface of the sample into consideration (after polishing and as cast – casting skin). The polished surfaces were characterized by higher resistance to cavitation erosion than the as-cast samples. On the other hand, the casting skin acted beneficially as an extra coating that prevented the castings’ cores from cavitation erosion damage. • Composite layers were fabricated in situ in cast steel and cast iron. • Hardness within area of composite zones reached more than 850 HV1. • Composite layers were testes by ball on disc method, Miller test and cavity erosion. • Composite layers were tested in as – cast state and after polishing process.

О ВЫБОРЕ СОВРЕМЕННОГО КОНСТРУКЦИОННОГО МЕТАЛЛИЧЕСКОГО МАТЕРИАЛА ДЛЯ МЕХАНИЧЕСКИХ СИСТЕМ ОТВЕТСТВЕННОГО НАЗНАЧЕНИЯ. ЧАСТЬ 1

It is shown that when solving the problems of assurance of quality, reliability, competitiveness of high-duty mechanical systems, metal and a complex of its mechanical and service properties are of fundamental importance. Steel cast iron MONICA (Mo–Ni–Cu) (patent BY, no. 15617) exhibits an unconventional and unique ability to lose brittleness (increase viscosity) with increasing strength. In terms of service properties, it is not inferior to alloyed heat-strengthened steels. This makes it possible to recommend it for the manufacture of various highly loaded parts and assemblies of modern technology. The article provides several examples of the effective use of MONICA for the manufacture of cast knives for cutting and chopping devices of forage harvesters (Hi-Tech), large-sized gear wheels with a diameter of 500 mm for final drives of agricultural combines (know-how), as well as experimental cast rails for railway transport (Hi-Tech). A complex of laboratory and full-scale tests has convincingly proved that one brand of a new structural material fully provides the required operational reliability of many and different tribo-fatigue systems, the performance of which is determined by many criteria (fatigue, wear, friction, crack resistance) under the action of high repetitive variables and shock-cyclic loads. This determines the unconditional efficiency and competitiveness of critical mechanical systems (tribo-fatigue systems) for modern machines and equipment.

Sliding movement temperature analysis between composite conductor rail and a collector shoe

Electrical traction systems come in different forms, depending on the railway and terrain. The collector shoe is a critical component that impacts the train’s overall safety. The majority of collector shoes consist of several types of gray cast iron that are highly resistant to sliding wear. Wear is produced by friction and electrical current at temperatures over the melting point, which results in decreased sliding speeds. Applying an electric current to a sliding contact alters the process temperature of the wear without changing the sliding speed. The study is essential for industrial applications, especially in subway transit. This study aims to learn more about the wear characteristics of a composite aluminum–stainless steel conductor rail moving across a current collector. The authors employed a finite element analysis and a series of electric current testing. This research will produce some intriguing test findings. Based on a friction pair consisting of a composite conductor rail of aluminum and stainless steel and gray cast iron, a sliding friction contact model was built in the COMSOL finite element software. When the findings of the finite element analysis and the pin-on-plate test technique are compared, the maximum temperature variance is 10%, while the minimum temperature variation is 0.8%. Additionally, the results reveal that acclimation and rupture occur more rapidly when speed rises, and a steady temperature rise may be achieved more quickly.

Experimental Investigation of Triboelectrification Behaviour in the Friction Process

The triboelectrification phenomenon can occur during the friction process of metal contact pairs. An in-depth understanding of triboelectrification behaviour is incredibly beneficial to controlling friction and wear. However, due to the complexity of the driving mechanism, it is still challenging to gain a thorough understanding of the triboelectrification behaviour of metal–metal contact pairs. To further reveal the triboelectrification behaviour during the friction process of metal pairs, wear experiments of GCr15 steel–cast iron were carried out on a CFT-I tribometer under oil-free and oil lubrication conditions. The triboelectric current signal was collected during the investigation, and its variation was discussed. The result shows that the varying trend of the triboelectric current was consistent with that of the friction coefficient in the friction process. The triboelectrification of similar metal contact pairs primarily driven by material transfer was closely related to friction and wear conditions.

Influence of the thickness of the layer of internal deposits in pipelines of water supply and discharge systems on their remaining service life

Introduction. The practical operation of water supply networks, made of steel and gray cast iron, has proven that deposits accumulate on the inner surface of pipes under certain conditions. Deposition depends on the quality of transported water and the water flow regime, same as in gravity sewerage networks. A sediment layer accumulates in the flume of pipes if the actual flow rate is smaller than the minimum standard one. A layer of deposits in metal water pipes changes the value of the actual inner diameter of pipes and rises the pressure loss due to resistance along the pipeline length, which contributes to an increase in the energy consumption by the pumping equipment and affects the pressure value at the end point of a network. A layer of sediment in the flume of a gravity drainage network also rises losses along its length, slows down the flow rate and may block the water flow in the network. The purpose of the study is to find dependence between the remaining service life of water supply and sewerage networks, having internal deposits, and the thickness of the layer of deposits on pipe walls. Materials and methods. The authors use the dependences, that they have already derived for the hydraulic analysis of metal water supply networks and gravity sewerage networks, having internal deposits. Results. The authors have identified dependence between the remaining service life of water supply pipelines and sewerage systems and the thickness of deposits on the inner walls of pipes. Examples, confirming such a relationship, are provided. They are substantiated by graphs showing dependence between the remaining service life and the thickness of the layer of deposits in pipelines. A hydraulic criterion is proposed for projecting the term of operation of water supply and sewerage networks with internal deposits. Conclusions. The authors have proven the need to use special tables to analyze the characteristics of pipes within the framework of a hydraulic analysis of water supply and sewerage networks, having internal deposits.

The optimization of welding hardfacing on wear resistance of FC-25 grey cast iron steel substrate by response surface methodology (RSM)

This paper aimed to identify the optimal conditions for welding hardfacing by applying the Response Surface Methodology (RSM). The welding heat input, electrode type, and hardfacing layer on wear resistance of welding hardfacing were all optimized using the Box-Behnken experimental design. The findings revealed that these three variables had an impact on the volume loss of welding hardfacing. Because of the high coefficient of determination, the experimental data obtained were to a quadratic equation (96.90%). The ideal condition was determined using a 3D response surface plot and a contour map produced from mathematical models. The following were the ideal welding conditions: With a welding heat input of 1.58 J, a filler metal type of DFA2-600-B, and a third layer of hardfacing, the lower volume loss of the weld was 1.29 mm3.

Effect of the impact pulse on the dynamic fracture toughness behavior of high-strength steel and nodular cast iron

In this article, the effect of the impact pulse in dynamic fracture toughness tests with an instrumented pendulum impact test machine is investigated. Low-blow tests were carried out on Charpy specimens made from 42CrMo4 casting steel and nodular cast iron EN-GJS-400-18 with different crack geometries at several impact velocities. Inertia effects that occur on the specimens and on the components of the pendulum impact test machine were identified with laser-based measurements of displacement and velocity. The dynamic fracture toughness tests showed an incomplete energy conversion, as part of the applied energy is absorbed by the components of the pendulum impact test machine. This can lead to an overestimation of the loading, in terms of the J integral, on the specimen.

Procena čvrstoće snopa materijala metalnog zupčanika

Expressions for the pulsating or beam strengths of many popular metallic gear materials are derived based on the tensile strength and endurance ratio. The strength values predicted are for a reliability of 99% at load cycles corresponding to that of the endurance strength of the materials. The expressions are based on the consideration of the revised Lewis gear root stress formula by treating the design parameters as random variables associated with the lognormal probability density function and application of the Gerber fatigue failure rule. Pulsating strength predictions are compared with those of AGMA estimates for through-hardened steels and other materials. The variances between model predictions and AGMA values for steel and ductile cast iron materials are reasonably low. Low variances between model and AGMA values for high-strength gray cast iron and cast bronze were also observed. However, high variances between model and AGMA values for low-strength gray cast iron and cast bronze were found. Overall, the model estimates are considered sufficiently accurate for preliminary design applications where initial sizes of gears are generated. The study showed that for many metallic gear materials, the average pulsating strength ratio is 0.36 at 99% reliability. Therefore, the suggestion by Buckingham, that the fatigue strength of a gear tooth is approximately one-third (0.333) of the tensile strength of the material is justified.

ПОЛІПШЕННЯ ЕКСПЛУАТАЦІЙНИХ ВЛАСТИВОСТЕЙ ДЕТАЛЕЙ МАШИН ХОЛОДНИМИ ПЛАСТИЧНИМ ДЕФОРМУВАННЯМ

The article discusses the direction of improving the operational properties of machine parts by the cold plastic deformation. Purpose – to develop methods of experimental research of regular reliefs, including equipment, tools and material of prototypes; to create a classification of regular reliefs by purpose; to determine the mechanics of deepening of the linear indenter in the metal sample; to develop technological recommendations and research tools. The object of research – regular reliefs on the surface of machine parts. Methods and devices for conducting experiments were selected: hydrogenated presses, linear indentors, optical microscopes, microhardness testers, research materials, instruments and measuring instruments. The materials were alloy and stainless steel, gray and malleable cast iron, bronze and brass, aluminum and titanium alloys. The classification of reliefs by purpose, obtained by cold plastic deformation and cutting, has been developed. The mechanics of deepening of a linear indenter into a metal sample has been developed, which combines the values of the depth of indentation with the geometrical parameters of the indenter, friction coefficient, contact stress and groove depth. Experiments on 8 typical representatives of structural materials confirmed the theoretical principles of the mechanics of deepening. Scientific results allowed to develop and test a sample of the tool on a tubular part made of duralumin D16 (2117). The following process of improvement of operational properties of details of cars is offered: preparation of a surface under indentation; indenter deepening; removal of metal protrusions by cutting. KEYWORDS: REGULAR RELIEF, COLD PLASTIC DEFORMATION, LINEAR INDUCTOR, SURFACE OF PARTS, MECHANICS OF DEEPING

Study on Solid Particle Erosion of Pump Materials by Fly Ash Slurry using Taguchi’s Orthogonal Array

Various grades of stainless steel are used to fabricate the pump impeller, casings, and seals used in heavy-duty erosion and corrosion conditions. In the present study, stainless steel (SS316L, SS304, SDSS2507) and grey cast iron used in the fabrication of heavy-duty pump impellers were taken for the analysis of solid particle erosion. Experiments were conducted on the lab-scale slurry pot tester. Fly ash slurry was prepared of different concentrations (wt%). Taguchi’s orthogonal array is used to design the experiments of erosion wear for the variation of rotational speed, solid concentration, time, and particle size. Results showed that SS316L showed superior microhardness and wear behavior against the fly ash slurry followed by SS304, SDSS2507 and Grey cast iron.

МОДЕЛИРОВАНИЕ УСКОРЕННЫХ ИСПЫТАНИЙ НОЖЕЙ РЕЖУЩЕ-ИЗМЕЛЬЧАЮЩИХ АППАРАТОВ КОРМОУБОРОЧНЫХ КОМБАЙНОВ

A method is proposed and a technique is developed for accelerated bench tests in laboratory conditions of knives of cutting-reducing devices of forage harvesters. One of the main purposes of the developed method is an experimental comparative assessment of the long-term performance (according to the wear resistance criterion) of various knife options (according to the materials for their manufacture and structural and geometric parameters). The proposed test method solves the problem of assessing the wear resistance of agricultural harvester knives by two parameters: physical depreciation and dulling of their cutting edge. A flexible belt with an abrasive fixed on one of its surfaces is used as counter-specimens during testing, which allows for wear with sliding impact and thereby significantly accelerates the process of knives damage. The technique makes it possible to test simultaneously two knives made using different technologies, under comparable conditions. In addition, to speed up testing, not one, but several counter-specimens are mounted on the test equipment. As a result of such tests, the process of impact-fatigue loading with slipping is simulated and the damage to the knife is reproduced, which is close to the operational one: wear and an increase in the cutting edge radius. Using the developed technique, comparative accelerated tests of imported steel and domestic cast iron (produced by OJSC “Gomselmash”) knives made using various technologies were carried out. The tests conducted made it possible to quantify the difference in the service characteristics of the cutting drum knives made using various technologies, which confirms its usefulness and efficiency. The developed technique was approved in accordance with the established procedure and is used for bench testing of knives at OJSC “Gomselmash”.

Tribological Behavior of Two High Performance Railway Wheel Steels Paired with a Brake Block Cast Iron

ABSTRACT The wear behavior of two steels for tread-braked wheels (ER7+ and CLASS B+) against the same brake block cast iron was studied through pin-on-disc tests to understand the phenomena at the interface and compare the steels. The contact stress (0.61 MPa) and the sliding speeds (0.52 and 0.62 m/s) were set considering the UIC 510-5 (E) for technical approval of monobloc wheels. The friction coefficient, the weight loss of both steel pin and cast iron disc and the pin hardness were correlated with the damage of the pin. In addition, a preliminary thermal finite element model was proposed to predict the temperature of the pin contact surface. The experiments showed that a material transfer phenomenon from the cast iron disc to the steel pin and the subsequent detachment of the adhesion joints caused high friction coefficient fluctuations. The removal of the adhesion joints probably promoted the detachment of steel particles from the pin, which could explain the high weight loss and remarkable delaminations of the pin in some of the studied conditions. On the contrary, small friction coefficient fluctuations and red oxide formation due to the temperature increase were detected when the material transfer was very limited. ER7+ steel showed lower weight loss and less damage than CLASS B+ at the lowest sliding speed, the contrary was observed at the highest sliding speed. Finally, the simulation showed that the maximum temperature of the pin contact surface varies between 61 and 97 °C, which is consistent with the red oxide presence.

Behaviour and applications of ionic liquids as lubricants in tribology: A review

The increasing demands of environmental awareness and investigations in green lubricant technology in different industries has led to substantial attention towards biodegradable based oils and ionic liquids (ILs) as lubricants. ILs are organic salts consisted of several anions and organic cations that melt normally below 100 °C. ILs have eco-friendly properties such as non-volatility, high oxidative stability, non-flammability and high thermal conductivity. Due to the good thermal properties, ILs can be used as neat lubricants or as additives under severe tribological environments for which conventional lubes are failed to perform well. The use of ILs as lubricants in metal cutting and in tribological pairs (metal to metal contacts) has substantiated their adsorption ability on the surfaces, forming thick tribo-films which reduces friction and wear. This paper reviews the physical effects, sustainability and the tribological performance of different ILs in tribo-pairs (i.e. steel-steel, steel-cast iron and steel-aluminium etc.) and in metal cutting processes followed by a discussion of wear protection and friction reduction mechanism based on surface tribofilm characterization.

Comparison of Stress-Strain States of Rail-Wheel Pair Made of Steel and MoNiCa

Contact interaction in a wheel-rail pair and its corresponding stress-strain state for various combinations of materials of this pair and the weights of passenger and freight cars were considered. The materials under study were steel and high-strength cast iron based structural material MoNiCa with strength and wear-fatigue characteristics close to steel ones.The load on each wheel was: 53.9 and 294.3 kN for an empty and loaded freight car, 146.8 kN and 230.5 kN for an empty and loaded passenger car. The bottom surface of the rail was rigidly fixed.Young's modules were adopted as follows: 200 GPa for steel and 165 for MoNiCa. The results of finite element calculations of the three-dimensional stress-strain state showed that the largest von Mises stresses of 613.08 MPa occur in the wheel (steel)-rail (steel) pair of the loaded freight car. For all types of loading, the lowest stresses (15.8 % – 16.7 % less than in the steel-steel pair) are observed in the wheel (MoNiCa)-rail (MoNiCa) pair. This indicates the appropriateness of using MoNiCa for the manufacturing elements of the wheel-rail system.

Adaptation of Fracture Mechanics Methods for Quality Assessment of Tungsten Carbide Cutting Inserts.

Tungsten carbide (WC) is well known as one of the hardest materials widely used in machining, cutting and drilling, especially for cutting tools production. Knowing fracture toughness grants the opportunity to prevent catastrophic wear of a tool. Moreover, fracture toughness of WC-based materials may vary because of different material compositions, as well as a different way of production. Hence, each material should be treated individually. In this paper, SM25T (HW) tungsten carbide (HW—uncoated grade, TNMR 401060 SM25T, manufactured by Baildonit company, Katowice, Poland) was taken into consideration. Sintered carbides—designated as S—are designed to be applied for machining steel, cast steel and malleable cast iron. Fracture mechanics methods were adapted to make a quality assessment of WC cutting inserts. Both quasi-statical three-point bending tests, as well as Charpy dynamic impact tests, were performed to calculate static and dynamic fracture toughness (KIC and KID, respectively). In addition, a special emphasis was placed on the microscopic analysis of fracture surfaces after impact tests to discuss material irregularities, such as porosity, cracks and so-called “river patterns”. There is a lack of scientific works in this field of study. However, cutting engineers are interested in obtaining the experimental results of that kind. Although there are a few standardized methods that may be used to determine fracture toughness of hard metals, none of them is expected to be the most reliable. Moreover, there is a lack of scientific works in the field of determining static and dynamic fracture toughness of WC by the presented method. The proposed examination solution can be then successfully used to calculate toughness properties of WC-based materials, as the results obtained seem to be with a good agreement with other works.

FUNCTIONAL ELECTROCHEMICAL COATINGS IN DUAL-USE TECHNOLOGIES

Technological approaches to the application of functional electrochemical coatings in civil and military technologies are analyzed. It is shown that the existing technical solutions are aimed at solving the problems of strengthening and protection of surfaces and detoxification of environments from pollutants of natural and man-made origin. Electrochemical coatings based on the iron triad, doped with refractory metals, increase corrosion resistance, microhardness and wear resistance of surfaces. Doped with transition metals heteroxide coatings, which are synthesized by the method of plasma electrolytic oxidation on aluminum and titanium alloys have catalytic properties to neutralize toxic substances in the gas and liquid phases. Peculiarities of electrochemical formation of functional coatings on construction materials of different types are investigated. It is shown that cathodic deposition by direct and pulsed current on low-carbon steel and gray cast iron forms uniform ternary coatings of Fe-Mo-W and composite systems of Fe-Co-Mo (Fe-Co-W), which have increased corrosion resistance and mechanical properties compared to base metal material. The obtained thin-layer coatings are recommended for the restoration and strengthening of worn surfaces, in particular in the technology of repair of weapons and military equipment. It was found that plasma-electrolyte treatment of piston silumin in alkaline solutions based on diphosphates synthesized heteroxide systems that are active in reducing the number of toxic emissions of internal star engines and reducing hourly fuel consumption. It is shown that nanocomposite coatings on titanium show photocatalytic activity on the destruction of model pollutants. The obtained materials have a set of enhanced functional properties and are promising for use in industrial and repair production, including the security and defense sector.

Design and analysis of disc brake system in high speed vehicles

Brakes are the most important component of any automobile. Brakes provide the ability to reduce or bring automobile to a complete stop. The process of braking is usually achieved by applying pressure to the brake discs. The main objective of this research paper is to propose an appropriate design and to perform analysis of a suitable brake rotor to enhance the performance of the high-speed car. The design of the brake disc is modelled using Solid works and the analysis is carried out using Ansys software. The analysis has been conducted by considering stainless steel and grey cast iron using same brake rotor design so that optimal choice of brake disc can be considered. The analysis considered involves static structural analysis and steady state thermal analysis considering specific parameters on brake rotor to increase the life of brake rotor. From the analysis it is found that the performance and life of disc brake depends upon heat dissipation. From the analysis results it can be concluded that grey cast iron has performed better as compared to stainless steel as this material has anti-fade properties which improves the life of the brake rotor.

Microstructural Characterization, Tribological and Corrosion Behaviour of Forged and Cast Grinding Balls a Comparative Study

Various facilities are used in mineral processing to prepare raw material. Practically, two types of balls are used, cast balls and forged balls. They are respectively made from high chromium cast iron and forged steel and are supplied in different sizes and chemical compositions. The cast and forged balls have different microstructures and consequently display dissimilar wear behavior. The target aimed in this work is to achieve a comparative study taking into account the type of microstructure, mechanical properties, and wear behavior of these two kinds of materials. Specimens have undergone chemical, metallographic and XRD characterizations. Subsequently, these samples were subjected to hardness measurements, abrasion and friction tests in order to evaluate their wear behaviour. Tribological tests, under unlubricated environment, are carried out on both types of grinding balls in order to study the wear system. Corrosion tests are also performed on forged steel and high chromium cast iron ball samples. The obtained results reveal a large difference in terms of chemical composition and microstructural components. Chromium cast iron balls are more resistant to friction, whereas forged balls are more resistant to abrasion. Additionally, the corrosion tests reveal a narrow discrepancy in corrosion behaviour between the studied materials.