Malleable Iron Research Articles

Hopper-skeletal and hemispherical crystallization of graphite in iron–carbon–silicon alloys

The growth of graphite during solidification and solid-state transformation of Fe–C–Si alloys continues to be the subject of extensive research. This is particularly valid for spheroidal graphite, as control of graphite shape is vital to achieving the level of performance required in contemporary applications of these casting alloys. For irons solidifying in the stable system, growth of spheroidal graphite typically starts in the liquid before the eutectic reaction, and then continues through carbon diffusion from the liquid to the austenite through an austenite shell, to finally being completed through growth in solid state because of decreased carbon solubility during cooling or iron carbide decomposition if metastable solidification also occurs. The process may be complicated by partial or even complete metastable solidification. This last scenario is typical for industrial malleable iron. To further understand graphite growth mechanisms, irons of similar composition but with four level of Mg (<0.01–0.047%) were rapidly solidified in copper molds to produce samples with metastable eutectic. The samples were annealed at 950 °C for 4–40 min to promote graphite growth, and then quenched in water. Optical and scanning electron microscopy on polished and deep etched specimens was used to study the growth kinetics of nucleation and growth of graphite. Sequential nucleation of graphite on complex Mg sulfides that have nucleated on Mg oxides was documented. Unique features such as honeycomb structure typical for hopper skeletal-type crystals analogous to ice crystals, and hemispherical growth of graphite aggregates in Fe–C–Si alloys were observed and documented. The experimental findings are additional support of the multi-mechanism theory of graphite growth in iron alloys.

Static and Dynamic Analysis of Selective Leverage System Gear Train

Nowadays, the mechanical advantage is strongly emphasized in a mechanical system. Therefore, the most modern gearboxes are used to increase the torque without also increasing their output speed while reducing it. In this study, Selective Leverage System (SLS) gear train is generated in Solidworks 2016 and together with dynamic motion study and static simulation analysis. Dynamic motion analysis is performed to provide output speed of SLS gear train. It can be concluded that the gear system runs with unchanged speed (RPM) for input and output which is approximately the same with theoretical value in Selective Leverage System patent. The maximum output torque is evaluated by using theoretical calculation. At every 90° rotation, maximum value of output torque is produced. The results are validated and compared to the analytical value of patent. For static simulation analysis, the stress distribution of T-shaped lever of Selective Leverage System gear train is identified by using composite material compared to the existing gear materials. The static simulation analysis between Aluminium Alloy, S45C Steel, Malleable Cast Iron and Glass Filled Polyamide are compared and composite materials are capable to be used as a material of gear train components instead of current material, S45C Steel for better result.

Iron decarburisation techniques in the eastern Guanzhong Plain, China, during Late Warring States period: an investigation based on slag inclusion analyses

Iron production in the Central Plains area of China has been largely based on cast iron smelting since ca. fifth century BC, with different techniques developed in the following Warring States period and Han dynasty to convert this material into malleable soft iron. Whilst there is a broad consensus about the evolution of technological traditions in the Early Iron Age, the methodologies employed for differentiating artefacts derived from different iron smelting and decarburisation methods have been variable and not sufficiently conclusive. Taking advantage of renewed analytical approaches and archaeological evidence recovered in recent years, this paper summarises our current understanding of the decarburisation techniques employed in Early Iron Age China and sheds new light on this subject through the analysis of archaeological artefacts from two civilian cemeteries in the eastern part of the Guanzhong Plain (Shaanxi), dated to the third century BC. The analytical results indicate that both solid-state and liquid-state decarburisation were employed for soft iron production in this area during the Late Warring States period. The methodology employed in this paper, based on slag inclusion analysis, also provides a more systematic approach to differentiating soft iron production techniques in future archaeometallurgical research in China.

Microstructure and Mechanical Properties of Spark Plasma Sintered Si3N4/WC Ceramic Tools.

Silicon nitride (Si3N4) based ceramic tools exhibit good machinability in cutting materials such as gray cast iron, ductile iron, malleable cast iron, and superalloys due to excellent high-temperature mechanical properties. In this paper, high-performance Si3N4-based ceramic tools containing tungsten carbide (WC) and cobalt (Co) were studied. Effects of the WC content and Co content on mechanical properties and a microstructure of Si3N4-based ceramic materials were analyzed. Results showed that Si3N4-based ceramic material containing 10 wt % WC and 1 wt % Co had the best comprehensive mechanical properties at a sintering temperature of 1650 °C and holding time of 6 min, achieving Vickers hardness, fracture toughness, and room temperature bending strength of 16.96 GPa, 7.26 MPa·m1/2, and 1132 MPa, respectively. The microstructure of Si3N4-based ceramic tool material is uniform without obvious abnormal growth. The Si3N4-based ceramic tool was mainly composed of α-Si3N4, β-Si3N4, and WC phases.

Tellurium Effect on ASTM A 220 Graphite Malleable Cast Iron

The result of investigation of tellurium malleable cast iron are presented in the paper. Various small quantity of tellurium are added in the ladle before pouring molten metal. The main aim of investigation was determination of the influence composition of tellurium on graphite microstructure and mechanical properties. In addition, the final mechanical property of composition determined by hardness measurements. The favourable influence of the addition of tellurium into malleable cast iron molten metal on the tested properties after annealing as well as an percentation of graphite structure from 2% up to 6.5% and increase hardness from 38 HRc up to 43 HRc

An efficient method of foundry and metallurgical coke quality improvement

At foundry coke production, introduction into a coal burden comparatively small amount of non-sintering carbonaceous additives is one of effective methods of the coke mechanical, physical and chemical properties intended control. A review of industrial tests on coal burdens coking with different thinning additives, carried out at coking plants of Western Siberia and the Urals, presented. Coke dust of coke dry quenching facility was used as additives, as well as oil-coke and semi-coke fines, and rubber crumb. Under industrial conditions of JSC “Altaj-koks” and JSC “Koks” coke dust of coke dry quenching facility was tested as a thinning additive. After introduction into the burden of 1.6–3.0% of coke dry quenching facility dust, the coarseness and mechanical strength of foundry coke increased. The industrial burden coking with oil-coke fines was accomplished at JSC “Altajkoks” Nos 1 and 2 coke-oven batteries. Oil-coke fines in the amount of 5% was added to a burden (у = 15–16 mm) without change of coking regime (the period of coking is 15–16 h). Strength of foundry coke (М40) increased by average 0.5%, of BF coke – by 1.2%, ash content decreased by 0.3%, sulfur content increased by 0.03–0.06%, reaction ability decreased by 19% (rel.). At the OJSC “Gubakhinsky koks” it was determined by industrial tests, that it is possible to produce a metallurgical coke, meeting requirements of non-ferrous metallurgy, providing up to 5% of oil-coke fines are added instead of the same amount of low-sintering coals. VUKHIN’ studies showed, that still higher effect in improving foundry and BF coke quality can be reached by introducing into the coal burdens “modified” oil coke up to 50% as a coking additive. During industrial tests at JSC “Altaj-koks” semi-coke fines were introduced into production burden instead of KCH coal in the amount of 3–7%. At its utilization a burden crushing degree decreased down to 76.5%, dust content (class 0.5–0 mm) decreased down to 39.1%, its bulk density increased up to 780 kg/m3 . At that the coke mechanical strength corresponds to that for coke made of industrial burden, and its coarseness increased. Results of successful industrial tests of foundry coke made of burdens with coke dry quenching facility dust and oil coke fines at smelting in cupola gray cast iron and malleable cast iron.

Sorting nipple castings from malleable cast iron from the result of measuring their residual magnetization

The physical principles of magnetic control of the structure of malleable cast iron compact castings are summarized. It reports on the technical features and mode of operation of the automated instrument used for control. The features of formation of remanent magnetization of unhealed castings of nipples from malleable cast iron with bleached surface layer, features of the influence of changes in the layer thickness on the result of magnetization of the castings are established. A criterion for sorting castings with thickness of the bleached layer was developed based on the result of measuring its residual magnetization a given. Recommendations on its use when adjusting the rejection limit for automated magnetic sorting of castings by structure at the Minsk plant of heating equipment are given.

Striking Iron: The Art of African Blacksmiths

Striking Iron: The Art of African Blacksmiths

Motion and Stress Analysis of Cam System for Marine Diesel Engine 93 KW

The developments of maritime sector in Indonesia shows increasing demand for ships. Especially ships with size of 30 GT has problem with low availability of the ship engine, which most of the ships still use non marine diesel engine as its main propulsion. The problem gives interest to make a step to improve by design marine diesel engine using reverse engineering method. Cam system of marine diesel engine design was needed to be calculate to select the material and the motion. The design of cam system needs study about the stress analysis in cam system to make sure the distribution of force and moment. The result of stress analysis was used to select material of components in cam system. The motion analysis result was used to be input data of stress analysis. The condition to obtain the stress of components was on maximum condition, its contain pressure, torque, rotation, and force. All component that calculated are camshaft, lifter (flat-tappet), push rod, rocker arm, spring, and valve. Each component was given two different materials and material selection was based on safety factor of each component. Material for camshaft and lifter were malleable cast iron, for push rod and rocker arm were mild steel, for spring was ASTM A231, for intake valve was steel JIS SUH3, and for exhaust valve was steel JIS SUH35. The result of motion analysis were angular velocity of camshaft with value was 2400 deg/sec, friction force between camshaft and lifter with maximum value was 125.393 N, and contact force between camshaft and lifter with maximum value was 845.307 N, and linear velocity of intake valve with maximum value was 696.573 mm/s, and linear velocity of exhaust valve was 463.734 mm/s.

Failure of malleable cast iron sprinkler pipe end cap due to freezing of water within

Abstract Failures in end caps of sprinkler firewater systems frequently occur due to the freezing of the water inside the sprinkler systems on cold winter days. In these failures, a flat top of an end cap of a sprinkler system fails and completely separates from the threaded body of the end cap. In this study, metallurgical investigations including fractography, metallography, EDS analysis, and hardness measurement were performed for the failure analysis of the end cap. Finite element analysis was employed to identify both the maximum stress location and the maximum stress magnitude resulting from the freezing of and interaction between the ice and end cap when temperature dropped below the freezing point. Microstructure observations confirmed the ferritic malleable cast iron of the end cap. The hardness of the end cap was significantly below the hardness range specified for standard ferritic malleable cast iron. Small cracks formed during the casting of the end cap and the low strength of the end cap caused the final fracture. Failure stress determined by finite element analysis simulating the freezing of the inside water could accurately predict the failure stress and failure temperature. High tensile stress and poor manufacturing quality caused the crack to propagate in the cleavage mode and at the final stage in the ductile mode.

A new type of antifriction and wear resistant malleable cast iron

There is developed a technology of malleable cast iron modification on the basis of complex chemical compound of surface-active elements and their solid solutions with other elements. Silicon high content in malleable cast iron helped to develop a power efficient technology of graphitizing annealing which has considerably lower annealing temperature and complete renunciation of the second graphitizing annealing stage at the expense of its change by controlled cooling up to ferrite structure or by air cooling for perlite structure.

Эволюция нерегламентируемых форм графитных включений в графитизированных конструкционных чугунах

The evolution influence of the graphite form (from a platetype form to a globular one) upon structural cast iron properties was analyzed and grounded, there were also considered cast iron peculiarities and prospects of their commercial application is estimated. For castings production the expediency of rational application of unregulated graphitized cast iron with the intermediate transitional morphology of graphite inclusions instead of grey iron high grades with lamellar graphite (GI 30, GI 35) and malleable cast iron is shown. The appropriate use substantiation of mentioned cast iron types taking into account their peculi-arities is shown.

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.

Criteria of shape recognition for cast iron

The aim of this study was to determine the criteria for recognising cast iron types by calculation of areas of graphite images. For this purpose, graphites are discretised from images of six different shapes given in the standard TS EN ISO 945-1 and processed with the developed software. Binary images of graphites were obtained with the developed image processing software. Different criteria are tested on binary images. The most acceptable criterion is evaluated for the determination of the types of cast irons. The criterion is defined as the ratio of graphite area to the large circle area (GA/LCA). The calculation of the large circle area is made by drawing a circle from the gravity centre of graphite. The radius of the circle is the farthest point of the graphite image. GA/LCA ratio is always smaller than 0.3 for grey cast iron and greater than 0.7 for ductile iron. Ratios between 0.3 to 0.7 are for malleable cast irons. Average GA/LCA values are calculated as 0.0540 for shape I, 0.1354 for shape II, 0.2578 for shape III, 0.4394 for shape IV, 0.5410 for shape V and 0.8368 for shape VI respectively.

Assessment of the Mean-Stress Sensitivity Factor Method in Stress-Life Fatigue Predictions

Abstract The mean-stress sensitivity factor model developed by Schütz in 1967 is considered the most comprehensive method to account for the mean-stress effect on high-cycle fatigue life and strength, which is applicable to various materials (such as steels, steel castings, ductile irons, malleable cast irons, grey cast iron, wrought aluminum alloys, and cast aluminum alloys) and to a broad mean-stress or stress-ratio range. Even though the mean-stress sensitivity factor method has been frequently used in European-based fatigue commercial software and engineering design codes, such as the Rechnerischer Festigkeitsnachweis für Maschinenbauteile (FKM) Guideline, it has not received a great deal of attention worldwide. Although the FKM Guideline provides extensive experimental test validation, very little evidence from independent sources have illustrated the validity of this method. Thus, it is the objective of this paper to examine the Schütz mean-stress sensitivity factor model by comparing the Walker mean-stress correction equation to the best fitting parameters published for steels, aluminum alloys, and titanium alloy. It was concluded that the Schütz mean-stress sensitivity factor model exhibits a reasonable degree of agreement with the Walker equation over a wide variety of materials.

Development of technology for strengthening gray cast iron components by heating in contact with iron scale

Reaction of cast iron base with iron oxide FeO at 1173–1373 K is studied. It is shown that oxidation of cast iron base carbon promotes transformation of ferrite into austenite, and with rapid cooling this is converted into martensite. The hardness of ferritic-pearlitic cast iron after quenching is commensurate with that of malleable cast iron.

可鍛鋳鉄の衝撃特性におよぼすB，Al，Ni，Zn，Zr，Sn，TeおよびBiの影響:―可鍛鋳鉄の靭性の向上に関する研究―

可鍛鋳鉄の衝撃特性におよぼすB，Al，Ni，Zn，Zr，Sn，TeおよびBiの影響:―可鍛鋳鉄の靭性の向上に関する研究―

A new PM route for machinable, malleable iron

Research disclosed at the recent PowderMet 2012 show in Nashville provides evidence that PM can indeed hold its own against malleable iron, ductile iron, and compacted-graphite iron castings. Joe Capus, Metal Powder Report consultant editor, reports.

Effect of aluminum on stability of retained austenite in bainitic malleable cast iron

The effect of aluminum additives on the microstructure of bainitic malleable cast iron after heat treatment consisting of isothermal hardening at 350°C in a bath with molten lead after a hold at 920°C for 90 min is studied. A metallographic study is performed by the methods of light and scanning electron microscopy and x-ray diffraction analysis of the metal.

Effect of the shape of graphite inclusions on acoustic characteristics of articles from cast and deformed iron

The effect of the structure, of graphite inclusions in particular, on acoustic characteristic of gear pairs from malleable and high-strength iron obtained by casting and hot plastic deformation is studied.