Grades Of Cast Iron Research Articles

A surface and sub-surface quality evaluation of three cast iron grades after grinding under various cutting conditions

Grinding is one of the most common finishing processes used in the manufacture of metal components that require a combination of both smooth surface finish and tight tolerances. Despite the abundant knowledge concerning this process, specific literature is still scarce regarding the grinding of different cast iron grades. These materials have a wide application in the automotive industry, notably in the manufacture of gears, crankshafts, and valve control shafts. In this sense, this paper presents an experimental study of the peripheral surface grinding of three grades of cast iron grades (gray, nodular, and compacted graphite) with two SiC abrasive grinding wheels. The input variables tested were two values for depth of cut (15 and 30 μm) and two worktable speeds (5 and 10 m/min). The output variables analyzed were surface roughness, microhardness, microstructures, and SEM images of the ground surfaces. The results showed that gray cast iron provided the best performance concerning surface and sub-surface integrity among the three cast iron grades tested, whereas the nodular cast iron exhibited both worst finishing and superficial texture. No microstructural changes were observed in the samples of gray and compacted graphite cast iron grades, irrespective of the cutting conditions investigated, unlike for the nodular cast iron grade in which microstructural change was detected. The ranking order for the grindability of the three cast iron grades in terms of roughness, microhardness and surface texture investigated in this paper is gray cast iron, compacted graphite iron and nodular cast iron.

Mechanical Properties and Impact Toughness of Nickel and Aluminum Alloyed High Silicon Ductile Iron

High silicon grades of ductile cast iron are known to be highly advantageous in regard to technically relevant properties and economic efficiency. In particular, the outstanding mechanical properties lead to an increasing demand since 2011, the year of incorporation to the EN 1563 standard. However, low impact resistance and spontaneous failure are concerns that limit the application, especially at lower temperatures. Silicon serves as a solid solution strengthener. By the addition of cobalt, aluminum and nickel as additional solid solution strengthener, an improvement in mechanical properties compared to only silicon could be obtained. Previous studies showed that the addition of 1.5 wt.% Ni to an EN-GJS-500-14 grade with 3.8 wt.% Si resulted in a tensile strength of 650 MPa at 15 % elongation. In the present study, silicon was substituted stepwise by nickel and aluminum, simultaneously aiming at the retention of the mechanical properties of the EN-GJS-500-14 grade. By decreasing the silicon content to 3.3 wt.% Si at 1.1 wt.% Ni and 0.2 wt.% Al, EN-500-14 was obtained. Even though, the presence of pearlite in the matrix was observed, this substitution of silicon led to an increase in Charpy-V-notch toughness by 4 Joule at room temperature. For further alloy design of high silicon ductile cast iron for simultaneously substituting silicon and improving the mechanical properties and notch toughness, the restrictions for pearlite formation must be complied.

Additive Manufacturing and Casting Technology Comparison: Mechanical Properties, Productivity and Cost Benchmark

Abstract The casting technology is one of the oldest production technologies in the world but in the recent years metal additive manufacturing also known as metal 3D printing has been evolving with huge steps. Both technologies have capabilities to produce parts with internal holes and at first glance surface roughness is similar for both technologies, which means that for precise dimensions parts have to be machined in places where precise fit is necessary. Benchmark tests have been made to find out if parts which are produced with metal additive manufacturing can be used to replace parts which are produced with casting technology. Most of the comparative tests have been made with GJS-400-15 grade which is one of the most popular cast iron grades. To compare mechanical properties samples have been produced using additive manufacturing and tested for tensile strength, hardness, surface roughness and microstructure and then the results have been compared with the samples produced with casting technology. In addition, both technologies have been compared in terms of the production time and production costs to see if additive manufacturing is competitive with the casting technology. The original paper has been written in the Latvian language as part of the Master Thesis within the framework of the production technology study programme at Riga Technical University.

Long crack growth and crack closure in high strength nodular cast iron

In the context of wind turbines, highly stressed structural components are often made of EN-GJS-700-2. This high strength nodular cast iron grade is characterized by an almost purely pearlitic matrix resulting in a comparatively low toughness. Therefore and due to inevitable casting defects, a fracture mechanical strength assessment, additionally to a conventional one, is often required. However, it lacks a detailed characterisation of EN-GJS-700-2 in terms of fracture mechanical material parameters. Thus, the objective of this study was to derive a comprehensive description of long crack growth for this cast iron grade.For this purpose, profound experiments were performed on raw material taken from a real planet carrier. Crack growth was analysed under varying loading conditions whereby the impact of the stress ratio and the maximum stress intensity factor was of special interest. The threshold behaviour was described in terms of two threshold values. Relevant crack closure mechanisms were analysed in detail: plasticity, oxidation and surface roughness. The latter one was identified as the most dominating mechanism. Three different approaches to describe crack closure were derived. Its integration into a crack growth law yielded a uniform description in terms of an effective stress intensity factor. To describe crack growth in a less complex way, two other crack growth laws, based on a two-parameter approach respectively on the maximum stress intensity factor, were derived.

Efficiency of use of the solid-state YAG: Nd-Laser for hardening of high-strength cast iron VCH 70-3

The method to increase the durability of high-strength cast iron with spherical graphite YAG:Nd-laser radiation is proposed. The results of studies in laser processing of cylindrical samples of high-strength cast iron grade of the VCH 70-3 are presented by the YAG:Nd-laser, working in pulse-periodic mode. Effect of the treatment with 1 kW YAG:Nd-laser on microhardness of high-strength cast iron has been investigated. More effective laser strengthening is found to be occurred by YAG:Nd-laser processing as compared with continuous CO2-laser one. The results showed that when processing of cast iron in general, the zone of laser influence consists of the reflow zone and the zone of quenching from the solid state. The optimal values of parameters of the hardened layer in the radiation by the solid-state YAG:Nd laser are considered. It is shown that under fluence of laser radiation fluence more than 28 j/mm2 is occured the surface melting of cast iron.

Automatic classification of cast iron grades using support vector machine

In this study, classification of three grades of cast iron viz., gray, malleable and white, based on their texture is attempted, using Haralick features extracted from gray level co-occurrence matrix (GLCM) and histogram features extracted from local binary pattern (LBP). The features were extracted from three hundred images stored in a database and are utilized to train and test the support vector machine (SVM), to classify microstructures. The experimental results show that LBP based feature extraction achieves high accuracy when compared to GLCM based features in classifying cast iron grades.

Synthesis of nomogram for the calculation of suboptimal chemical composition of the structural cast iron on the basis of the parametric description of the ultimate strength response surface

Based on the mathematical model describing the effect of carbon (C) and the carbon equivalent (C EQ ) on the ultimate strength (US) of structural cast iron, a parametric description of the response surface US = US (С, С EQ ) is performed. It is shown that, for the model considered in the form of a regression equation, the application of ridge analysis makes it possible to find a set of suboptimal values of the input variables (С, С EQ ) that ensure the production of specified grades of structural cast iron. A graphical representation of such sets forms a nomogram for calculating the suboptimal chemical composition of structural cast iron

Austempered Ductile Iron (ADI): A Review

Abstract Austempered ductile iron (ADI) is a group of ductile irons offering the design engineers remarkable mechanical properties. It exhibits an excellent combination of high strength, ductility, toughness, fatigue strength, and exceptional wear resistance that is unavailable in other grades of cast iron. Austempered ductile iron is almost twice as strong as the regular ASTM grades of ductile iron, whilst still retaining high elongation and toughness characteristics. In addition to the exceptional wear resistance and fatigue strength, it enables designers to reduce a component's weight and costs for equivalent or improved performance. Therefore, ADI has become an attractive and economic substitute for forged steel and cast steel in many engineering applications. This led to marked interest in ADI in the past few years with considerable research work to understand the effect of processing parameters on its characteristics and mechanical properties. The objective of this paper was to review works that have been conducted over the past years on the effects of process variables, mechanical properties, benefits, and applications of ADI.

Formation and Utilization of Nanostructures Based on Carbon During Primary Aluminum Production

Results are given for comprehensive research concerning fields of metallurgy, nanomaterials, and ecology. Taking account of theoretical concepts and known practice of modifying gray cast iron, a new ultrafine modifier is considered containing carbon with increased chemical activity. It is established that carbon foam, electrolyzer dust from electric filters, and alumina passing through a dry gas cleaning system, have carbon nanostructures in their composition. Raw material composition for preparing modifying additive, procedures, and experimental materials are provided. Results are given from a series of cast iron melts with a different modifier content and a method for adding it with replacement of 50% of standard metallurgical graphite by the carbon-containing part of carbon foam. The effect of modifier on phase formation during gray cast iron solidification by means of cooling from a liquid condition is considered. A test cast iron sample and reference cast iron are analyzed chemically, and mechanical properties are analyzed. It is established that a modifier makes it possible to improve gray cast iron grade. Theories are proposed for carbon nanotube formation during aluminum production. A technology is provided for extracting carbon structures from starting raw material. It is shown that with preparation of one ton of aluminum using the production solutions developed for decontamination and utilization of industrial waste it is possible to produce modifier based on highly organized carbon nanostructures.

STATISTICAL EVALUATION OF FATIGUE DATA OF COMPONENTS

A variety of steels, cast iron grades and other metals have long been used for the production of machine components. In recent years, however, new materials such as sintered materials and plastics become increasingly important. Because of the large number of different fibers, matrices, stacking sequences, processing conditions and processes and the variety of resulting material configurations it is not possible to rely on proven fatigue models for conventional materials. Moreover, the development of models, which are valid for all composites are generally extremely difficult. In this work, a possible application of high-performance composites as materials for machine elements are investigated. This study attempts to predict the fatigue behavior and the consequent durability, based on laboratory measurements. Using the statistics program JMP, the aquired data was subjected to a reliability analysis in order to ensure the plausibility, validity and accuracy of the measured values.

Metallographic study of articles of the Kamensk iron foundry and iron works produced in the 18th–20th centuries

Results have been presented for studies of the microstructure and chemical composition of a number of articles made of iron and cast iron at the Kamensk plant, which cover the period from the start of the production of iron on the territory of the city of Kamensk-Ural’skii at the turn of the 17th–18th centuries to the beginning of the 20th century. Differences in the composition of the Kamensk cast iron and modern grades of foundry cast iron have been established. Possible sources of technological difficulties and production waste at the Kamensk plant have been revealed. The potential of metallographic studies for the attribution of historical articles made of ferrous metals are shown.

Improvement Corrosion Resistance of Gray Cast Iron Grade FC220 on Chromizing Process by Separate Cr Powder and NH<sub>4</sub>Cl Powder System

A new configuration of chromizing process was developed by separating Cr powder from NH4Cl. FC220 gray cast iron specimens were chromized in this new experimental setup at 450, 550, 650,750, 850 and 950°C during 13 hours in order to study the possibility of chromizing at “low” temperature. The chromized specimens were examined using Scanning Electron Microscopy (SEM), macro-hardness, micro-hardness, compression test and salt spray test. The results shows that the specimen chromized at 650°C gives the best compromise between the corrosion resistance and the hardness of the FC220 with 1.73 ڌm of thickness of the chromized layer. However, after 13 hours of the process, the hardness of the FC220 specimens decreased considerably from 93 HRB to 64.2 HRB (31%).

Fatigue strength of nodular cast iron with regard to heavy-wall applications

Abstract For a proper estimation of the fatigue life of a heavy-walled cast component made of nodular cast iron, sufficient knowledge regarding the cyclic properties of the material is necessary. Based on the material parameters at hand for component design, different fatigue analysis procedures can be used. Elastic and elastic-plastic approaches can be adopted, with the latter being reserved only for local approaches. The present publication summarizes the cyclic material parameters gained during a research project by extensive material tests under stress and strain controlled cyclic loading at different load ratios for three nodular cast iron grades. In addition to an improved knowledge of the cyclic material behavior, the notch, the size effects and the mean stress sensitivity were of special concern during the investigations in order to provide an entire overview of the tested materials and thus input information for both stress and strain based design approaches. Tests were performed for specimens taken from large cast blocks of the nodular cast iron grades EN-GJS-400-18U-LT and EN-GJS-450-18, both with ferritic matrices, and EN-GJS-700-2 with a pearlitic matrix. For some of these materials, mean stress sensitivities above 0.5 were obtained during the investigations. These values are not covered by the common standards, which calculate lower values for the mean stress sensitivity. Cyclic material parameters for stress and strain controlled tests are given in this paper as well as values for the size effect, based on the concept of the highly stressed volume. The effect of different specimen sizes could be shown not only by stress but also by strain controlled tests.

Thermal Analysis—Theory and Applications in Metalcasting

Monitoring and adjusting the chemical composition and the nucleation potential of casting alloys melts is critical to the production of castings of consistent high quality. While other methods such as fractured test samples (e.g., the wedge test for gray iron) and spectrographic chemical analysis deliver useful information, thermal analysis (TA) (also called cooling curve analysis, CCA) can provide a more complete insight in the dynamic changes occurring upon melting and during melt treatment of casting alloys. Initially TA was used for the rapid evaluation of the carbon equivalent (CE) in cast iron, or the silicon content in Al-Si alloys. Extensive research then extended the capabilities of TA to the understanding of the solidification changes induced by compositional variations such as the Mn/S ratio, Ce and Mg additions. With the advent of ever faster computers, the first derivative of the cooling curve, which is the cooling rate, was added to the arsenal of data provided by TA, and a new technique, Computer Aided Cooling Curve Analysis (CA-CCA), was born. This technique evolved then into Differential Thermal Analysis (DTA) without a reference sample. With this tool in hand the metallurgist ventured to predict not only the chemistry of the melt but also the nucleation potential (degree of inoculation), the shrinkage propensity, the dendrite arm spacing and the grain size, the graphite shape, the solidification microstructure, and even the room temperature microstructure. Currently, different TA techniques are used worldwide in the daily production of all grades of cast iron, as well as in monitoring the melting of aluminum and steel alloys. From this short introduction it should be obvious that the story of DTA/CCA is a long and exciting one. This paper will try to summarize the fascinating development and extraordinary success of this technique in the casting industry.

Assimilation of Advanced Roll Materials in Rolling Production

The EVRAZ ZSMK 250-1 continuous small-section mill specializes in manufacture of rebars Nos. 10 and 12 and equal-flanged angles Nos. 2–4 from billets 100 ×× 100 mm in cross section. Rebar manufacture is carried out by a slitting process from carbon and low-alloy steels for different standards governing rib transverse shape. The life of finishing stand reinforcing passes is mostly determined by channel shape at the bottom of grooves within which transverse ribs are formed. The lowest life of finishing stand passes is observed in rolling crescent shaped ribs. There is surface breakdown in these passes with formation of cracks and spalling. Cracks form during the first use of a set of rolls. Cracks penetrate to a depth up to 15 mm in rolls with high hardness. Tests are performed for different grades of cast iron for rolls of the finishing group with a minimum hardness of 60 HRC to a controlled depth of 15 mm from the roll body surface. The best operating properties are obtained in rolls of cast iron with a spheroidal graphite shape, alloyed with chromium, nickel, molybdenum, and vanadium.

Graphitized Cast Irons

An analytical review of data on general-purpose grayed cast iron with different forms of graphite (lamellar, vermicular, globular, flaked) is presented. Grades of cast iron, their compositions, special features of structure of the graphite, and properties of gray, high-strength and malleable irons are described. The data on the kinds of iron considered are compared with those stipulated in international and some national standards.

Solution Strengthened Ferritic Ductile Cast Iron Properties, Production and Application

The ductile cast iron standard in Europe also considers new ductile cast iron grades with a unique combination of tensile strength with high elongation (e.g. Rm 72520 psi with A514%) achieved by the solution strengthening of the ferritic matrix by silicon with contents between 3% and 4.3%. The new grades tolerate a higher amount of pearlite and carbide stabilizing elements without the generation of embrittling pearlite or carbides in the microstructure. The presence of Cr, Mn, and V do not influence the elongation significantly. An advantage of the new cast irons is the cost efficient machining due to lower tool wear. The tool life with the machining of the fully ferritic grades GJS-500-14 and GJS-600-10 is about 50–60% longer in comparison to the ferritic-pearlitic grades. The investigated grades show very good cyclic mechanical properties but lower dynamic properties. The pre-condition to achieve optimized properties by well-shaped graphite nodules, achievable with special inoculation techniques, adjusted to the high silicon content and the solidification rate, otherwise threaten graphite degenerations. There is no increased danger of dross generation or of a worsening flowability (investigated with special test equipment). Also the supposed inclination to the generation of porosities with the higher Si content was not confirmed.

Effect of silicon content and defects on the lifetime of ductile cast iron

In this work, the influence of microstructure on the mechanical properties has been studied for different grades of ferritic ductile cast iron. Mechanical tests were carried out and the effect of silicon on the resistance of material was well noticed. An increasing silicon content increases the strength and decreases the ductility of material. The lifetime and endurance limit of material were affected by the presence of defects in material and microstructure heterogeneity. Metallurgical characterizations showed that the silicon was highly segregated around graphite nodules which leads to the initiation of cracks. The presence of defects causes the stress concentration and leads to the initiation and propagation of cracks.

Free Vibration and Material Mechanical Properties Influence Based Frequency and Mode Shape Analysis of Transmission Gearbox Casing

The main objective of this research work is to study the effect of mechanical properties of materials on natural frequency and mode shapes of heavy vehicle gearbox transmission casing. Material mechanical properties play an important role for evaluation of frequency, deformation, stress and strain. Four materials have different density and the origin of material is also different. Grey cast iron has damping property, structural steel has high density and rigidity, Al and Mg alloys have low density. Free vibration study was performed for the vibration response study of casing. Grey cast iron grade FG 260, Structural Steel, Al alloy and Mg Alloy materials were analyzed on the design and vibration index. The free vibration study of casing was performed using finite element simulation. The vibration response for all materials shows the variation of natural frequency (1002-3879) Hz and various vibrations mode shapes. The vibration responses for first twenty modes were studied. Solid Edge and Pro-E was used for CAD designing of transmission gearbox casing. FEA based ANSYS 14.5 is used for modal analysis. Fixed- fixed constraint based boundary condition was used by constraining the connecting bolts hole. The transmission casing is tightly mounted on vehicle frame using connecting bolts. Loose transmission casing causes heavy noise and vibration problem. The simulation results were compared with experiment results available in literature.

Nodular Cast Iron – Fatigue Crack Measurement and Simulation

Study presented in this paper is concerned with fatigue crack initiation detection, crack propagation observation and measurement as well as with numerical simulation of damage accumulation and propagation in the nodular cast iron grade EN-GJS-400-18-LT. Material properties of nodular cast iron are well elaborated in previous authors' papers. Crack initiation and its propagation observation as well as crack length measurement is performed on standardized specimens using ARAMIS 4M optical system. Based on the experimental results, a new three-dimensional constitutive model is proposed to simulate the low-cycle fatigue behaviour of considered material. An efficient algorithm for modelling cyclic plasticity is used for performing numerical simulation of crack initiation and growth on standardized specimens made from nodular cast iron. The computational procedure accuracy is verified by comparing the computed results with the real experimental data.