Ductile Iron Research Articles

Examples of Chunky Graphite Formation in Production of Ductile Iron Castings and Effective Countermeasures

Examples of Chunky Graphite Formation in Production of Ductile Iron Castings and Effective Countermeasures

Effect of CeO2 Nanoparticles Addition on Tribological Behavior of Austenitic Ductile Iron

Effect of CeO2 Nanoparticles Addition on Tribological Behavior of Austenitic Ductile Iron

Effect of Copper Addition on Microstructure and Mechanical Properties of Ductile Cast Iron

Effect of Copper Addition on Microstructure and Mechanical Properties of Ductile Cast Iron

Structural and Phase Analysis of the Ausferritic Ductile Cast Iron Matrix Obtained by Heat Treatment and in the Raw State

Structural and Phase Analysis of the Ausferritic Ductile Cast Iron Matrix Obtained by Heat Treatment and in the Raw State

PM and Rheocasting in Ductile Iron Castings

PM and Rheocasting in Ductile Iron Castings

Enhancing Hardness Characterization in Austempered Ductile Iron with Jellyfish Swarm-Adaptive Hybrid Adaboost Approach

Enhancing Hardness Characterization in Austempered Ductile Iron with Jellyfish Swarm-Adaptive Hybrid Adaboost Approach

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.

Reproduction of fissure corrosion and mechanism for fissure formation on ductile cast iron

On some cast iron pipes corroded under tensile stress, corrosion with a characteristic surface appearance, known as “fissure corrosion,” was occasionally observed. Because fissure corrosion on ductile cast iron pipes has been rarely studied, the detailed conditions and mechanism for fissure formation are still elusive. In this study, the levels of tensile stress and anodic current density causing fissure corrosion on ductile cast iron were investigated through laboratory experiments to reproduce fissure corrosion and elucidate its mechanism. Fissure corrosion was reproduced at bending tensile stresses ≥200 MPa. The depth difference between the peak and valley of fissures increased with increasing anodic current density, and the fissure corrosion was attributed to the difference between the anodic current densities of the peak and valley due to plastic deformation by stress concentration. Fissure corrosion was likely to be suppressed by reducing the anodic current flowing out of ductile cast iron surface.

Correction: Effect of anode passivation on ferrate(VI) electro-generation using ductile iron anode and application for methylene blue treatment

Correction: Effect of anode passivation on ferrate(VI) electro-generation using ductile iron anode and application for methylene blue treatment

CALPHAD-Based Modeling and Experimental Validation of Silicon Effect on the Solidification Behavior of Novel SiNb Cast Irons

The low oxidation resistance of SiMo ductile cast irons used as exhaust manifold material at high temperatures necessitates the development of new generation ductile cast iron compositions. New alloy designs can be made using CALPHAD methodology, and solidification sequence, segregation and critical phase transformation temperatures can be determined, especially for the solidified bulk materials. Thus, in commercial practicality, castable compositions with a raised A1 temperature can be obtained. In this study, novel SiNb cast irons with varying silicon contents were developed as candidate materials for exhaust manifolds. Solidification sequence, microsegregation, phase transformations, equilibrium phases of hypereutectic compositions containing 4 to 7 wt pct Si were calculated by CALPHAD-based modeling. The bulk materials of the studied compositions were cast as Y blocks and metallurgical analyzes were carried out. Studies revealed that; (i) in the ferritic matrix of the cast irons, graphite, Nb-rich carbides and some pearlite existed, (ii) pearlite formation was due to the negative segregation of silicon and positive segregation of manganese during solidification, (iii) as silicon content increased the amount of silicon dissolved in ferrite phase increased in the solidified structure and as a result pearlite formation decreased at the cell boundaries, and amount of vermicular graphite increased, (iv) depending on the silicon content the critical A1 temperature varied between 860 °C to 1013 °C and these values were higher than that of SiMo cast iron. All these findings revealed that SiNb cast irons had phase stability at higher temperatures compared to SiMo cast iron.

Microelectrode investigation of iron and copper surfaces aged in presence of monochloramine.

Ductile iron and copper coupons were aged 137-189 days and 2 days, respectively, with 2 mg Cl2 L-1 monochloramine under four water chemistries (pH 7 or 9 and 0 or 3 mg L-1 orthophosphate). Subsequently, microelectrode profiles of monochloramine concentration, oxygen concentration, and pH were measured from the bulk water to near the coupon reactive surface, allowing estimation of flux and apparent surface reaction rate constants for monochloramine and oxygen. Both metals showed similar trends with orthophosphate where orthophosphate decreased metal reactivity with monochloramine (pH 9) and oxygen (pH 7). Comparing iron and copper coupons, apparent surface reaction rate constants for monochloramine and oxygen were one and two orders of magnitude greater, respectively, for iron coupons under all conditions. Overall, this research provides the first insights into monochloramine concentration, oxygen concentration, and pH by direct measurement near ductile iron and copper reactive surfaces aged in the presence of monochloramine.

Microstructure and mechanical properties of SiMo ductile cast irons alloys with varied Mo and Nb contents

Four silicon and molybdenum (SiMo) ductile cast irons (DCI) alloys were produced with the intention of evaluating the possibility of substituting molybdenum (Mo) by niobium (Nb) for cost reduction purposes. These alloys were evaluated in terms of their chemical composition, microstructure, hardness and tensile properties at room and high temperatures (800 °C). Results show that substitution of Mo by Nb does not change the mechanical properties of the DCI alloys significantly either at room or high temperatures.

EVALUATION OF AUSTEMPERING STUDY OF FERRITIC CAST IRON

In this study, the effect of austempering temperatures on the structural characterization of ferritic spheroid cast irons was analyzed. Austempering was the austenitization of the materials in the temperature of 900 ºC for an adequate period to obtain a complete austenite structure and then quenching to an interval temperature. Subcritical diffusion times were achieved at 320, 420, and 520 ºC ausferrite temperatures for period of 1.5 h. Metallurgical description of samples was defined using optical microscopy, energy dispersive spectrometry, X-ray diffraction, microhardness. The austempering temperature had a remarkable effect on the phase variations of the ferritic ductile cast irons. The higher degree of austempering produced a coarser structure called ausferrite.

Improving the Abrasion Resistance of Nodular Cast Iron Castings by Remelting Their Surfaces by Laser Beam.

This paper presents the results of research conducted in the field of the technology of surface hardening of castings from unalloyed and low-alloy nodular cast iron using the laser remelting method. The range of studies included macro- and microhardness measurements using Rockwell and Vickers methods as well as metallographic microscopic examinations using a scanning electron microscope. Moreover, abrasive wear resistance tests were performed using the pin-on-disk method in the friction pair of nodular cast iron-SiC abrasive paper and the reciprocating method in the friction pair of nodular cast iron-unalloyed steel. Analysis of the test results shows that the casting surface layer remelting by laser for unalloyed nodular cast iron results in a greater improvement in its resistance to abrasive wear in the metal-mineral system, as compared to low-alloy cast iron. Additionally, carrying out the laser hardening treatment of the surface layer made of the tested grades of nodular cast iron is justified only if the tribological system of the cooperating working parts and allowable dimensional changes during their operation are known.

Effect of laser remelting scanning speed on microstructure and abrasion resistance of laser cladded Fe-based alloy coatings

In this work, Fe-based alloy coatings were prepared on ductile iron substrates by laser cladding and laser remelting was used to further improve the abrasion resistance of the coatings. The result shows that increasing the remelting speed can gradually refine the microstructure and fully releases the residual stresses, and the inter-dendritic mesh structure becomes finer and denser. Compared with the original coating, remelted coatings have a significant increase in hardness and hardness uniformity. At the higher remelting speed of 40 mm/s, the coating had the highest hardness and abrasion resistance, 113.08 % and 157.55 % of the original coating, respectively.

Structural integrity and hybrid ANFIS-PSO modeling of the corrosion rate of ductile irons in different environments

Ductile iron (DI) samples were immersed in near-neutral, alkaline sodium hydroxide (NaOH), and sodium chloride (NaCl) environments for 180 days. The influence of microstructure on the corrosion resistance of three DI specimens was investigated. Microstructures, electrochemical measurements, and the characterization of the corroded surfaces were analyzed. The experimental results from this study were used to validate a model generated from hybrid adaptive neuro-fuzzy inferences system-particle swarm optimization (ANFIS-PSO) algorithms. The hybrid ANFIS-PSO modelling technique was improvised for a detailed evaluation of corrosion rate of ductile cast iron materials in different environments. The integrated hybrid ANFIS-PSO model revealed a sharp rise in localized corrosion caused by chloride-induced structural deterioration at the nanoscale for some of the grains. The performance results revealed that the fuzzy c-mean (FCM) clustering outperformed other clustering approach in the neuro-fuzzy model. Accuracy values of 92.9% and 93.7% were recorded for the training phase of ANFIS-FCM and ANFIS-PSO-FCM respectively for corrosion rates. The percentage error of the ANFIS-PSO predictions is significantly lower than the ANFIS-standalone prediction. This shows that the ANFIS-PSO with FCM approach is a better model for predicting corrosion rates. This will contribute to the body of knowledge for ductile iron, corrosion, and corrosion modelling using machine learning.

Evaluation of Cutting Temperature and Optimization in Milling of GGG60 Cast Iron

Spheroidal graphite cast irons have increased ductility, tensile strength, and toughness compared to other cast irons. Additionally, it can be mentioned that choosing spheroidal graphite cast iron over steel material has a better machining feature. In this study, Face milling operations were carried out using GGG60 material and different inserts, feed, and depth of cut. The Taguchi method was used for the experimental design, and 27 experiments were carried out. During the experiments, a thermal camera measured the temperature from the cutting zone. Experimental results were evaluated with analysis of variance and graphics, and cutting parameters were optimized. As a result of the optimization, optimum parameters for minimum temperature, TiAlN coated insert, 300 m/min cutting speed, 0.30 mm/tooth feed rate, and 0.5 mm depth of cut were found. According to the results obtained from the study, the most influential parameter affecting the temperature was the cutting speed. In addition, the TiAlN-coated insert has been observed as the most suitable coating type for minimum temperature.

Microstructural Evolution During Welding of High Si Solution-Strengthened Ferritic Ductile Cast Iron Using Different Filler Metals

The paper deals in depth with characterizing bead-on-plate welds on EN-GJS-500-14 base metal, utilizing two filler metals: a pure Ni wire and a NiFe wire containing 45 wt pct Ni. The welds were conducted using the same heat input to ensure comparability in microstructure analysis. The microstructural observations were carried out using optical and scanning electron microscopies, X-ray tomography, X-ray diffraction analysis, and microhardness testing. Thermodynamic simulations using the non-equilibrium Scheil solidification model provide insights into the solidification process and the underlying metallurgical factors associated with the observed microstructural evolution. The observations revealed that the pure Ni wire deposited a softer fusion zone with graphite precipitation, while cementite precipitated in the fusion zone of NiFe alloy. The formation of martensite structures with different morphologies was the predominant microstructural evolution in the heat-affected zone of both welds. The partially melted zone of the pure Ni weld is narrower than the NiFe weld because more diffusion of Ni avoids widening the brittle structures in the partially melted zone. An unmixed zone in the form of a peninsula was exclusively observed in the fusion zone of the NiFe weld because of inadequate diffusion of Ni into the liquified materials along the fusion boundary.

Ni-Cu Alloyed Austempered Ductile Iron Resistance to Multifactorial Wear

The paper provides a discussion on the results of studies of the effect exerted by combined degradation factors typical of four types of wear: abrasion, impact–abrasion, tribocorrosion, and impact–abrasion–corrosion, conducted for chain wheels made of Ni-Cu alloyed austempered ductile iron. The studies consisted of determining the content of retained austenite in the structure of the cast irons in question, establishing the measures of wear following wear testing, and identifying the basic surface degradation mechanisms observed in the chain wheels tested following multifactorial wear processes. The chain wheels made of ADI were found to have sustained the greatest damage under the impact–abrasion–corrosion (three-factor) wear scenario, while the wear was least advanced in the abrasion (one-factor) wear case. Another observation derived from the studies is that the combined effect of dynamic forces, corrosion, and quartz sand-based abrasives causes increased surface degradation in the cast iron grades taken into consideration compared to processes characterised by a reduced number of degradation factors (i.e., one- or two-factor wear processes). Additional hardness tests and XRD analyses revealed that a distinctive effect attributable to combined degradation factors on the surface hardness increased value and implied that bench testing was followed by phase transition.

Effect of the incorporating of refractory NbC precipitates in intermetallic iron-aluminide coatings on corrosion and high-temperature oxidation behavior

This study aims to investigate the effects of growing niobium carbide (NbC) particles into intermetallic iron-aluminide (FeAl) coatings on ductile cast iron (SGI) by thermo-reactive diffusion technique (TRD). The study compares the corrosion and oxidation behavior of the FeAl-NbC coatings with SGI, FeAl, and NbC coatings. Corrosion tests were conducted through polarization tests in a 3.5 wt% NaCl solution, while oxidation tests were performed at 900 °C for 4, 16, and 64 h. Before and after corrosion and oxidation tests, the coatings were examined using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The findings show that FeAl coatings with NbC particles had lower graphite nodules, porosity, and surface roughness values compared to FeAl coatings. FeAl-NbC composite coatings provided better corrosion and oxidation resistance compared to untreated SGI, FeAl, and NbC coatings. The results of the comparative analysis of FeAl-NbC, FeAl, NbC, and untreated SGI specimens indicate that corrosion resistance in a 3.5 wt% NaCl solution and oxidation resistance at 900 °C followed the order FeAl-NbC > FeAl > NbC > SGI.