Cast Iron Steel Research Articles

Removal of Phosphorous from Steel Produced by Melting Sponge Iron in Induction Furnace

In secondary route of steelmaking, production through induction melting furnace contributes about 31 % of India’s total steel production. The main raw materials used are steel scrap, cast iron and sponge iron. In India, majority of the induction furnaces are operated using acidic lining of silica based ramming mass to produce structural steel where basicity cannot be maintained to remove phosphorous and sulphur. In the present work, efforts are being made to generate the experimental data for refining of steel in 750 kg induction furnace. The basicity is maintained by addition of CaO and MgO in the form of flux. The slag is made oxidizing in nature by addition of sponge iron in the bath. Oxidation potential of the slag is fulfilled by presence of FeO in sponge iron. In every single heat, samples of slag and metal are collected. The degree of dephosphorization obtained is as high as 82 %.

Temperature gradient in cooling down Fe-C-Cr alloy casting

The fragment of investigations of primary crystallization process of casting made from chromium cast steel and chromium cast iron contain about 17% chromium was described in the article. The analysis of change in temperature gradient on cross-section of cooling model casting was introduced. To the investigations was applied TGDA (thermal gradient and derivative analysis) method worked out in the Department of Foundry in Silesian University of Technology in Gliwice which consists in multi-drop measurement of cooling temperature in casting using thermocouple locate on the direction of transferring warm from the casting to mould. On the basis of registered cooling curves were worked out graphs of temperature gradient and its first derivative (curves TGDA). The changes of course of TGDA curves describe the kinetics of primary crystallization process on cross-section of the studied casting and provides of created primary structure. At the analysis of temperature gradient curves also was used TDA (thermal and derivative analysis) method.

Studying of Microstructural Effects of Surface Rolling in Materials of Railway-Car Wheel Axles by EBSD and Non-Destructive Magnetic Evaluation

Surface rolling is a cold-working technology for hardening the surface of components made from steel or ductile cast iron. This process is able to increase the hardness of surfaces and to improve fatigue properties, so it is usually used on the axles (shafts) of railway-car wheels. In this paper the influence of surface strengthening technology on the microstructure of the material of railway car wheel axles is studied by Vickers microindentation hardness test, optical microscopy, scanning electron microscopy (SEM) automated EBSD (Electron Backscatter Diffraction) and non-destructive magnetic evaluation.

Optimization of Abrasive Wear Behavior of High Chromium Cast Iron and Hadfield Steel

Abstract: Wear properties of two different crushers used for grinding raw materials of cement industry are compared us-ing pin on disk wear test. The wear test was carried out with different loads on a pin. Abrasive wear behavior of two crushers made of Hadfield steel and high chromium cast iron was evaluated by comparing weight loss, wear resistance, microhardness and friction coefficient. The results showed that abrasive wear of high chromium cast iron was lower than Hadfield steel because of the larger amount of carbides and higher work hardening in the steel at the higher applied loads. Increase in surface hardness of Hadfield steel was more noticeable compare to high chromium cast iron due to the work hardening and formation of the twining sites during the wear test. Owing to the presence of M 7 C 3 carbides in high chro-mium cast iron matrix, impact crushers exhibited higher friction coefficient. In addition, a wear loss equation was derived based on a real crushing condition. However, a new approach in optimization of the wear parameters was developed and wear behavior of the materials was predicted based on the maximum number of the effective factors. The optimization of the parameters by genetic algorithm showed that optimum wear loss for hammer and impact crushers under real condition is 5.2958 mg and 3.8449 mg, respectively. Results of the numerical simulation show that the genetic algorithm optimiza-tion is effective and very useful in designing the hammer and impact crushers. In addition, some recent patents on abra-sive wear behavior of the high chromium cast iron and Hadfield steel are discussed in details.

Scuffing Behavior of 4140 Alloy Steel and Ductile Cast Iron

Scuffing Behavior of 4140 Alloy Steel and Ductile Cast Iron

Optimization of Abrasive Wear Behavior of High Chromium Cast Iron and Hadfield Steel

Wear properties of two different crushers used for grinding raw materials of cement industry are compared using pin on disk wear test. The wear test was carried out with different loads on a pin. Abrasive wear behavior of two crushers made of Hadfield steel and high chromium cast iron was evaluated by comparing weight loss, wear resistance, microhardness and friction coefficient. The results showed that abrasive wear of high chromium cast iron was lower than Hadfield steel because of the larger amount of carbides and higher work hardening in the steel at the higher applied loads. Increase in surface hardness of Hadfield steel was more noticeable compare to high chromium cast iron due to the work hardening and formation of the twining sites during the wear test. Owing to the presence of M7C3 carbides in high chromium cast iron matrix, impact crushers exhibited higher friction coefficient. In addition, a wear loss equation was derived based on a real crushing condition. However, a new approach in optimization of the wear parameters was developed and wear behavior of the materials was predicted based on the maximum number of the effective factors. The optimization of the parameters by genetic algorithm showed that optimum wear loss for hammer and impact crushers under real condition is 5.2958 mg and 3.8449 mg, respectively. Results of the numerical simulation show that the genetic algorithm optimization is effective and very useful in designing the hammer and impact crushers. In addition, some recent patents on abrasive wear behavior of the high chromium cast iron and Hadfield steel are discussed in details. Keywords: Abrasive wear, genetic algorithm, Hadfield steel, hammer crusher, high chromium cast iron, impact crusher, optimization, wear resistance

Wearing Quality of Austenitic, Duplex Cast Steel, Gray and Spheroidal Graphite Iron

Wearing Quality of Austenitic, Duplex Cast Steel, Gray and Spheroidal Graphite Iron The current work presents the research results of abrasion wear and adhesive wear at rubbing and liquid friction of new austenitic, austenitic-ferritic ("duplex") cast steel and gray cast iron EN-GJL-250, spheroidal graphite iron EN-GJS-600-3, pearlitic with ledeburitic carbides and spheroidal graphite iron with ledeburitic carbides with a microstructure of the metal matrix: pearlitic, upper bainite, mixture of upper and lower bainite, martensitic with austenite, pearlitic-martensitic-bainitic-ausferritic obtained in the raw state. The wearing quality test was carried out on a specially designed and made bench. Resistance to abrasion wear was tested using sand paper P40. Resistance to adhesive wear was tested in interaction with steel C55 normalized, hardened and sulfonitrided. The liquid friction was obtained using CASTROL oil. It was stated that austenitic cast steel and "duplex" are characterized by a similar value of abrasion wear and adhesive wear at rubbing friction. The smallest decrease in mass was shown by the cast steel in interaction with the sulfonitrided steel C55. Austenitic cast steel and "duplex" in different combinations of friction pairs have a higher wear quality than gray cast iron EN-GJL-250 and spheroidal graphite iron EN-GJS-600-3. Austenitic cast steel and "duplex" are characterized by a lower wearing quality than the spheroidal graphite iron with bainitic-martensitic microstructure. In the adhesive wear test using CASTROL oil the tested cast steels and cast irons showed a small mass decrease within the range of 1÷2 mg.

Effects of phosphate addition on biofilm bacterial communities and water quality in annular reactors equipped with stainless steel and ductile cast iron pipes

The impact of orthophosphate addition on biofilm formation and water quality was studied in corrosion-resistant stainless steel (STS) pipe and corrosion-susceptible ductile cast iron (DCI) pipe using cultivation and culture-independent approaches. Sample coupons of DCI pipe and STS pipe were installed in annular reactors, which were operated for 9 months under hydraulic conditions similar to a domestic plumbing system. Addition of 5 mg/L of phosphate to the plumbing systems, under low residual chlorine conditions, promoted a more significant growth of biofilm and led to a greater rate reduction of disinfection by-products in DCI pipe than in STS pipe. While the level of THMs (trihalomethanes) increased under conditions of low biofilm concentration, the levels of HAAs (halo acetic acids) and CH (chloral hydrate) decreased in all cases in proportion to the amount of biofilm. It was also observed that chloroform, the main species of THM, was not readily decomposed biologically and decomposition was not proportional to the biofilm concentration; however, it was easily biodegraded after the addition of phosphate. Analysis of the 16S rDNA sequences of 102 biofilm isolates revealed that Proteobacteria (50%) was the most frequently detected phylum, followed by Firmicutes (10%) and Actinobacteria (2%), with 37% of the bacteria unclassified. Bradyrhizobium was the dominant genus on corroded DCI pipe, while Sphingomonas was predominant on non-corroded STS pipe. Methylobacterium and Afipia were detected only in the reactor without added phosphate. PCR-DGGE analysis showed that the diversity of species in biofilm tended to increase when phosphate was added regardless of the pipe material, indicating that phosphate addition upset the biological stability in the plumbing systems.

FEM analysis of voltage drop in the anode connector induced by steel stub diameter reduction

Primary aluminium production is a high-energy consumption process, and improving the energy efficiency of smelters could be economically viable. An issue in the Hall–Héroult prebake anode technology is the voltage drop in the anode connector caused by the thermo-electro-mechanical interface contact between steel stub, carbon anode, and cast iron thimble. Steel stubs are exposed to an extremely aggressive environment throughout their service life, involving thermomechanical stresses and chemical attacks that cause shape changes. To estimate voltage drop due to change in stub shape, a 3D finite element model (FEM) of a whole anode was developed and solved with the in-house code FESh++. Steel stub diameter variations were compared with a new stub configuration. Results show a voltage increase of about 10mV between new and damaged configuration simulations. This holds promising potential for improving energy efficiency. An experimental factorial design was used to determine the main factor in steel stub diameter variation affecting voltage drop in the anode connector assembly.

Mathematically Modeling Parameters Influencing Surface Roughness in CNC Milling

In this study, steel AISI 1050 is subjected to process of face milling in CNC milling machine and such parameters as cutting speed, feed rate, cutting tip, depth of cut influencing the surface roughness are investigated experimentally. Four different experiments are conducted by creating different combinations for parameters. In conducted experiments, cutting tools, which are coated by PVD method used in forcing steel and spheroidal graphite cast iron are used. Surface roughness values, which are obtained by using specified parameters with cutting tools, are measured and correlation between measured surface roughness values and parameters is modeled mathematically by using curve fitting algorithm. Mathematical models are evaluated according to coefficients of determination (R2) and the most ideal one is suggested for theoretical works. Mathematical models, which are proposed for each experiment, are estipulated.

Influence of defects on fatigue strength and failure mechanisms in the VHCF-region for quenched and tempered steel and nodular cast iron

Investigations are presented in this paper on quenched and tempered steel 42CrMoS4 from two batches, with two different tensile strengths (Rm=1100MPa, 1350MPa) but with similar microstructure, and a nodular cast iron EN-GJS-900-2 (Rm=930MPa). Fatigue tests with smooth (Kt=1) and notched (Kt=1.75) specimens were performed at R=−1 and R=0 up to the number of cycles N=2·109 in order to determine the fatigue strength behaviour and failure mechanisms, especially in the VHCF-region. Failure in smooth specimens often initiated at material defects such as oxides in the quenched and tempered steel and shrinkage holes in the nodular cast iron. Firstly, a fatigue strength analysis was performed that did not consider these defects. A possibility of analysis of experimental data including VHCF-results has been discussed. Next, a linear elastic fracture mechanics analysis was performed in order to describe the defect behaviour, assuming that the defects act like cracks. The results showed that there are lower limit or threshold values of the stress intensity factor range ΔK for crack propagation in both materials. Analysis of defects and defect distribution in run-out specimens confirmed this conclusion. From the comparison of the results with an S–N curve from the design code FKM-Guideline Analytical strength assessment of components, recommendations for design and assessment of components have been derived.

On the Relationship of Magnetic Response to Microstructure in Cast Iron and Steel Parts

Nondestructive eddy current technique has long been used to detect discontinuities in materials. However, recently, its application has been extended to characterize materials' microstructure and properties. In the present article, four mild carbon steel bars with different chemical compositions (AISI 1015, 1035, 1045, and 1080) were obtained in annealed condition. Besides, to determine the effect of microstructure, six ductile cast iron bars with the same chemical composition and different pearlite contents were prepared. The pearlite percentage and estimated hardness values were determined by eddy current nondestructive technique, and the results were compared with the data obtained from conventional metallographic and hardness testing methods. The results indicate that the eddy current is a sensitive comparative technique to detect the microstructure (directly) as well as the mechanical (indirectly) changes of mild carbon steel and ductile cast iron parts.

The influence of cryogenic processing on wear on the impact wear resistance of low carbon steel and lamellar graphite cast iron

The aim of this work was to investigate the influence of deep cryogenic processing (77 K) on the resistance to impact wear of two common engineering materials; low carbon steel and lamellar graphite cast iron. Both specimen types were subjected to identical deep cryogenic treatment and treated and untreated specimens of each material were tested for comparison. The specimens were subjected to repetitive percussion impact normal to their surface at 10 Hz (impacts per second) in a ball-on-flat configuration. These tests were carried out using a bespoke, reciprocating hammer type impact wear test-rig. The total number of impacts applied to a particular specimen ranged from 4500 to 72,000. The wear scar produced on each specimen was measured and the nature of any wear features and debris recorded. Selected specimens were further analysed to investigate the microstructural transformation between the cryogenically processed specimens and those that had been left untreated. The results of the work presented here suggest that cryogenic processing can have a positive effect on the impact wear resistance of Fe–C alloys.

Effect of abrasive size on wear of metallic materials and its relationship with microchips morphology and wear micromechanisms: Part 2

Abstract In this paper, the effect of abrasive particle size on the wear of three different metallic materials (AISI 1045 steel, aluminum alloy and gray cast iron) was investigated. Abrasive wear tests using a pin on alumina paper were carried out using abrasive sizes between 16 μm and 192 μm. The wear surface of the specimens was examined by SEM for identifying the wear micromechanism and the type of microchips (wear debris) formed on the abrasive paper. The results show that the mass loss for the AISI 1045 steel and for the aluminum alloy increases linearly with the increase of particle size until the critical particle size is reached. After the critical particle size is reached, the rate of mass loss of the aluminum alloy increases at a lower linear rate, and for the AISI 1045 steel the curve of mass loss is non-linear and flattens when the critical particle size is reached. The abrasive paper in contact with the AISI 1045 steel presents continuous microchips before reaching the critical particle size (about 116 μm) and after it, it presents deformed discontinuous microchips and abrasive fracture. The abrasive paper in contact with aluminum presents clogging and continuous microchips before the critical particle size (about 36 μm) and after it, it presents discontinuous microchips. The wear surfaces of the AISI 1045 steel and the aluminum alloy present microcutting as the main wear mechanism before reaching critical particle size, and after that, it presents microploughing as the main wear mechanism. The gray cast iron did not show a transition in the curve of abrasive size against mass loss. The morphology of the microchips was similar for the different sizes of abrasive (discontinuous). However, at smaller abrasive sizes, some thin continuous microchips and clogging were formed. The main abrasive wear micromechanism was microcutting for the different abrasives sizes tested. The results show that the effect of critical abrasive size on wear in metallic materials can be related with the wear micromechanisms and the microchips morphology.

Influence on Tribology Characteristic of the Steel-Cast Iron Friction Pair under Different Concentration of the Self-Repairing Additive and Mechanism Analyzing

The influence of frictional wear characteristics were investigated under the Self-repairing Additive condition with different concentration by using MMU-5G end-face friction and wear testing machine. The surface images of friction pair and their chemical composition were detected by using SEM and EDS. The result indicates different concentration has a great influence on frictional wear characteristics of friction pair. The Self-repair coatings are formed on the 45#steel worn surface while nothing on the cast-iron worn surface, study considers that metallographic structure and mechanical performance of cast iron are the prime causation resulting in no Self-repair coatings. Self-repairing Additive of the right concentration has remarkable effect on antifriction and wearing of cast iron.

Hardening Characteristics of Plain Carbon Steel and Ductile Cast Iron Using Neem Oil as Quenchant

The hardening characteristics of medium carbon steel and ductile cast iron using neem oil as quenching medium has been investigated. The samples were quenched to room temperature in Neem oil. To compare the effectiveness of the neem oil samples were also quenched in water and SAE engine oil the commercial quenchants. The microstructures and mechanical properties of the quenched samples were used to determine the quench severity of the neem oil. The result shows that hardness value of the medium carbon steel increased from 18.30HVN in the as-cast condition to 21.60, 20.30and 20.70HVN while that of ductile cast iron samples increased from 18.90HVN in the as-cast condition to 22.65, 20.30 and 21.30HVN for water, neem oil and SAE40 engine oil respectively. The as-received steel sample gave the highest impact strength value and water quenched sample gave the least impact strength. The impact strength of the medium carbon steel samples is 50.84, 41.35, 30.50 and 45.15 Joule and that of ductile iron is 2.71, 1.02, 0.68 and 1.70 Joule for as-cast condition, neem oil, water and SAE 40 engine oil quenched respectively. The microstructure of the samples quenched in the Neem oil revealed the formation of martensite. Hence, neem oil can be used where cooling severity less than that of water but greater than SAE 40 engine oil is required for hardening of plain carbon steels and ductile cast iron.

Use of Miniature Specimen Test and Finite Element Method for Evaluation of Yield Strength and Fracture Toughness in Metallic Alloys

Abstract The present paper describes the method for evaluation of yield strength and fracture toughness of three materials, namely, linepipe steel, aluminum (Al) alloy, and gray cast iron using miniature specimen test. Conventional standard test methods consume more material and money and may damage the integrity of the in-service component. Miniature specimen tests overcome all these demerits. A method is outlined to predict the yield strength and fracture toughness from the miniature test through the empirical relations. The validation of results has been carried out by conducting standard tensile and fracture toughness tests according to ASTM standards. Further, the finite element method has been used to simulate the miniature test. A close agreement is observed between the results of the miniature test and standard tests.

Reinforcement of Hadfield steel matrix by oriented high-chromium cast iron bars

To attain a wear-resistant material compatible with high hardness and high toughness, Hadfield steel matrix was reinforced by oriented high chromium cast iron bars, through inserting high chromium alloys flux-cored welding wires into Hadfield steel melt at 1500 ± 10 °C. The obtained composites were investigated by XRD, SEM, micro-hardness, three-body abrasion wear and impact toughness testers. The results show that the alloy powders inside the flux-cored welding wires can be melted by the heat capacity of Hadfield steel melt and in situ solidified into high chromium cast iron bar reinforcements tightly embedded in the matrix. The micro-hardness of reinforcements of the water-quenched composite is about four times higher than that of the matrix. The impact toughness of the water-quenched composite is higher than that of the as-cast composite and lower than that of Hadfield steel, and its fracture mechanism is very complicated and refers to brittle and ductile mixture fracture mode. The excellent impact toughness and better wear resistance of the water-quenched composite are attributed to combine fully the advantages and avoid the drawbacks of both Hadfield steel and high chromium cast iron. Additionally, in industrial application, the pulverizer plate produced by this composite, has also better wear resistance compared to the reference Hadfield steel pulverizer plate.

Investigation of the Influence of Surface Strengthening Technology on the Material of Railway Car Wheel Axles

Surface rolling is a cold-working technology for hardening the surface of components made from steel or ductile cast iron. This process is able to increase the hardness of surfaces and to improve fatigue properties, so it is usually used on axles (shafts) of railway car wheels. In this paper the influence of surface strengthening technology on the microstructure of the material of railway car wheel axles is studied by micro hardness tests, optical microscopy, scanning electron microscopy (SEM) and X-ray line profile analysis.

Effect of dendrite coarsening on the solidification of interdendritic liquid in iron alloys

The solidification of the interdendritic liquid in austenitic 110G13L steel and white cast iron is studied. In the absence of dendrite coarsening, the solidification mechanism of the interdendritic liquid in the manganese steel is shown to change and solidification occurs in the form of polycrystalline aggregates around dendrites from different centers. The relation between the standard solidification of the interdendritic liquid and the dendrite coarsening in iron alloys is grounded.