Heat resistant cast irons

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Some Results from the Investigation of Effects of Heat Treatment on Properties of Ni-Hard Cast Irons

Some Results from the Investigation of Effects of Heat Treatment on Properties of Ni-Hard Cast Irons

The cast irons alloyed with Ni and Cr, that have wide use in the production of castings with high resistance to abrasion, are known as Ni-hard. Since they are highly resistant to wearing, these materials are particularly suitable for applications involving wear caused by minerals, for example in grinding tools, in reducing, mixing and conveying equipment and systems and pumps [1]. Ni-hard castings can be considered as economic substitute for the carbon and manganese steels and in every other case when there is need for abrasion resistance but only when they are not completely expose to impacts. Nickel and chromium are the main alloying elements, but also there are some other elements depending of the content of the main elements. Ni-hard castings can be divided in two main groups. The first one is with lower content of chromium (1.5 – 3 mass %) and the second one with higher content (8-10 mass % Cr). The first group Ni-hard castings is mostly used when there is need of high abrasion resistance at lower or moderate impacts. As a result of the high strength and toughness, the second group is used when there is need of increased wear and impact resistance. The usual criteria for evaluating Ni-hard castings in exploitation conditions is the hardness that on the other hand depends of the microstructure. We should have in mind that not only the chemical composition, but also the cooling rate and the heat treatment have influence on the microstructure. [2]
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EFFECT OF ALLOYING ON TEMPERATURE OF TRANSFORMATION «PEARLITE – AUSTENITE» IN COMPLEX-ALLOYED WHITE CAST IRONS

EFFECT OF ALLOYING ON TEMPERATURE OF TRANSFORMATION «PEARLITE – AUSTENITE» IN COMPLEX-ALLOYED WHITE CAST IRONS

[Wear resistant foundry out of complex-alloyed white cast irons]. Moscow, Mashinostroeniye Publ., 1984. 104 p. 4. Efremenko V.G., Chabak Yu. G., K. Shimizu. K vyboru tekhnologicheskoy skhemy smyagchayushchey ter- micheskoy obrabotki vysokokhromistogo chuguna [About the choice of technological mode of softening heat treatment of high chromium cast iron]. Nauka ta prohres transportu. Visnyk Dnipropetrovskoho natsionalnoho universytetu zaliznychnoho transportu − Science and Transport Progress. Bulletin of Dnipropetrovsk National University of Railway Transport, 2014, no. 2 (50), pp. 103-110.
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Development of Low Cost Corrosion Resistant Fe-Cr-Mn-Mo White Cast Irons

Development of Low Cost Corrosion Resistant Fe-Cr-Mn-Mo White Cast Irons

Cast irons are basically binary alloys of iron and carbon having carbon exceeding its maximum solid solubility in austenite but less than the carbon content of iron carbide. However, like steels, cast irons have varying quantities of silicon, manganese, phosphorus and sulphur. Silicon plays an important role in controlling the properties of cast irons and for this reason, the term cast iron is usually applied to a series of iron, carbon and silicon alloys. Special purpose cast irons include white and alloy cast irons which are mainly used for applications demanding enhanced abrasion, corrosion or heat resistance. In present study, corrosion resistant cast irons are of our interest. A detailed review of literature disclosed that corrosion resistant alloy cast irons currently in use is a compound of high percentage of silicon, nickel and chromium. Hence is called as chromium-molybdenum irons. It is widely used for oxidizing purpose. However, it shows low mechanical strength and shock resistance. Hence it is less useful for applications related with high mechanical strength and shocks. Ni-resist irons are useful in various types of ambient. It has low strength and become unsuitable at temperature higher than 780 o C. High Ni- austenitic gray irons also
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LITERATURE SURVEY ON WHITE CAST IRON (LOW COST CORROSION RESISTANT FE-CR-MN-MO) DETAILED STUDY

LITERATURE SURVEY ON WHITE CAST IRON (LOW COST CORROSION RESISTANT FE-CR-MN-MO) DETAILED STUDY

The useful service temperature range of Silal is governed by its silicon content. Work carried out by White, Rice and Elsea [3], and Maitland and Huges [4] explains it best. Resistance against scaling and growth get enhanced by increasing the silicon content. For optimum combination of properties, the silicon content is kept in between 4.5 - 6.5%. Such a composition is very well suited for temperatures ranging from room temperature up to 9000C. For use at service temperatures exceeding 9000C, the silicon content of silal is increased up to about 11%. However, higher silicon content makes the iron weak and brittle at room temperature. The inherent brittleness of silal is not a problem at temperatures above 2600C. These irons have been used successfully for furnace and stoker parts, for burner nzzles, and for trays used in heat treating other metals.
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The Effect of Heat Treatment on the Dry sliding Wear Behaviour of as cast and Grain Refined and Modified, Gravity cast A356

The Effect of Heat Treatment on the Dry sliding Wear Behaviour of as cast and Grain Refined and Modified, Gravity cast A356

ABSTRACT: In this study, Al-Si alloy A356 grain refined and modified using Al-5Ti-1B and Al-10Sr respectively was cast in pre-heated permanent mold using liquid metallurgy route. They were further heat treated (T6) by solutionising at 540 0 C, quenched in water at 70 0 C and aged for 5 hours at 180 0 C. They were tested for hardness and wear resistance as per relevant ASTM standards. A quantum rise in wear resistance was observed in Grain refined, Modified and heat treated A356 compared to as cast A356, Grain refined and modified A356. The improvement in wear resistance may be attributed to the refined microstructure, grain refinement and modification and improved hardness due to heat treatment.
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Eutectic Carbides in Damascus steel Ledeburite Class (Wootz)

Eutectic Carbides in Damascus steel Ledeburite Class (Wootz)

Considered the nature of the change of the morphology of ex- cess carbides in Damascus steel (Wootz), depending on the degree of supercooling of the melt, heat treatment and plastic deformation. Discovered that some of blades Damascus steel has an unusual nature of origin of the excess cementite, which different from the redundant phases of secondary cementite, cementite of ledeburite and primary cementite in iron-carbon alloys. It is revealed that the morphological features of separate particles of cementite in Damascus steels lies in the abnormal size of excess carbides having the shape of irregular prisms. Considered three hypotheses for the formation of excess ce- mentite in the form of faceted prismatic of excess carbides. The first hypothesis is based on thermal fission of cementite of a few isolated grains. The second hypothesis is based on the process of fragmentation cementite during deformation to the separate the pieces. The third hypothesis is based on the transformation of metastable cementite in the stable of angular eutectic car- bide. It is shown that the angular carbides are formed within the original metastable colony ledeburite, so they are called “eutectic carbide”. It is established that high-purity white cast iron is con- verted into of Damascus steel during isothermal soaking at the annealing. It was revealed that some of blades Damascus steel ledeburite class do not contain in its microstructure of crushed ledeburite. It is shown that the pattern of carbide heterogeneity of Damascus steel consists entirely of angular eutectic carbides. Believe that Damascus steel refers to non-heat-resistant steel of ledeburite class, which have similar structural characteristics with semi-heat-resistant die steel or heat-resistant high speed steel, differing from them only in the nature of excess carbide phase. D.A. Sukhanov1, L.B. Arkhangelsky2
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Influence of Semi Solid Isothermal Heat Treatment on Microstructure of Gray Cast Iron

Influence of Semi Solid Isothermal Heat Treatment on Microstructure of Gray Cast Iron

Mn, 0.1% Cu, 0.03% Cr and 0.04% Ni was cast into 50 mm Y blocks made from green sand moulds. The differ- ential scanning calorimetric analysis (DSC) for the stud- ied gray cast iron sample of 70.900 mg was conducted using NETZSCH STA 409 C/CD showing liquidus tem- perature of 1242˚C and solidus temperature of 1156˚C. Specimens of approximate dimensions 20 × 20 × 15 mm were cut from both side of the Y blocks for microstruc- ture examination and graphite morphology measurements. All of the test specimens were sampled from the same position in the Y blocks and the top sections of the blocks were rejected in order to avoid variations in gra- phite morphology and porosity. All specimens were heat- ed to 1163˚C hold for 5, 10, 15, 20 and 25 min, respec- tively in an electrically heated resistance furnace with heating rate of 10˚C·min −1 . After the semi-solid heat treatment, the samples were taken out immediately for both water quenching and still air cooling. Samples iso- thermally heat treated and water quenched is only con- sidered for study the change for graphite morphology.
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4 Textbook Integrated Product Design& DEvelopment 2010.pdf

4 Textbook Integrated Product Design& DEvelopment 2010.pdf

Steel refers to an iron-based alloy containing less than 2% carbon by weight. These alloys are formed by heating to a temperature between 723 ° C and 1148 ° C to fully dissolve the carbon in the interstitial spaces between the iron atoms, in a process known as austenitization, and then cooling the solid solution to room temperature. The hardness of the steel depends on the cool- ing rate. Fast cooling rates form a hard, brittle steel microstructure known as martensite, while slower cooling rates form a soft, ductile steel microstructure known as pearlite. The final prod- uct can be cast, that is, poured from the molten state to a near-net or final shape, or wrought, where the material is plastically deformed into the desired shape using such processes as rolling and forging. Steel is considered a plain carbon steel when it contains less than 2% total alloy- ing elements and when no minimum content is either specified or required for additives such as chromium, cobalt, columbium (niobium), molybdenum, nickel, titanium, tungsten, vanadium, or zirconium. Variations in the carbon content have the greatest effect on the mechanical properties, with increasing carbon content leading to increased hardness and strength and reduced ductility. Plain carbon steels are generally subdivided into low-carbon steels, medium-carbon steels, and TAbLE 8.3
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Rebuttal to Irons

Rebuttal to Irons

Dover in Review: A Review of Judge Jones' Decision in the Dover Intelligent Design Trial,.. http://www.discovery.org/scripts/viewDB/index.php?command=view&id=3135 (Jan..[r]

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Effect of Repeated Tempering on Abrasive Wear Behavior of Hypoeutectic 16 mass% Cr Cast Iron with Molybdenum

Effect of Repeated Tempering on Abrasive Wear Behavior of Hypoeutectic 16 mass% Cr Cast Iron with Molybdenum

hypoeutectic 16 mass % Cr cast irons without and with Mo was investigated. After annealing, the specimens were austenitized at 1323 K for 5.4 ks and cooled by fan air cooling. The hardened specimen was repeatedly tempered, at most three times at 748 ­ 798 K for 7.2 ks. The abrasive wear resistance of heat-treated specimens was evaluated using a Suga wear tester (two-body-type abrasive test). In the as-hardened state, the hardness did not change but the V £ increased gradually with an increase in the Mo content. In the tempered state, the hardness curves showed a secondary hardening as the t N increased due to the precipitation of secondary carbides and transformation of destabilized austenite to martensite.
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Two Body and Three Body Types Abrasive Wear Behavior of Hypoeutectic 26 mass% Cr Cast Irons with Molybdenum

Two Body and Three Body Types Abrasive Wear Behavior of Hypoeutectic 26 mass% Cr Cast Irons with Molybdenum

Alloyed white cast irons containing 15 ­ 30 mass % Cr (hereafter shown by %) have been employed as abrasive wear resistant materials for more than 50 years. The microstructure of these alloys consists of eutectic chromium carbides with high hardness and strong matrix providing the excellent wear resistance and suitable toughness. It is well known that 15 to 20% Cr cast irons have been commonly used for rolling mill rolls in the steel plants, while cast irons with 25 to 28% Cr have been applied to rollers and tables of pulverizing mills in the mining and cement industries. High chromium cast irons with hypoeutectic composition are preferable because they are free form primary carbides that reduce the toughness. 1 ­ 3) As-cast microstructure of hypoeutectic composition consists of austenite dendrite and eutectic M 7 C 3 carbides. Under
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EFFECT OF HEAT TREATMENT PROCESSES ON DUCTILE CAST IRON MECHANICAL PROPERTIES - AN EXPERIMENTAL APPROACH

EFFECT OF HEAT TREATMENT PROCESSES ON DUCTILE CAST IRON MECHANICAL PROPERTIES - AN EXPERIMENTAL APPROACH

Ductile cast iron is the most important material which is used in many industrial and automobile applications. In the present work the effects of austempering, normalizing and annealing heat treatment processes on Ductile Iron specimen are studied. Various temperatures and holding times are used in the present work. Maximum hardness is observed in austempered (at 860ºC) ductile iron specimen and minimum hardness value is observed in annealed (at 900ºC). Tensile strength is observed maximum in normalized (at 925ºC) specimen and minimum value observed in annealed (at 860ºC) ductile iron specimen.
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Improvement of the Properties of Aluminium Alloys

Improvement of the Properties of Aluminium Alloys

The classification dividing aluminium alloys according to their process characteristics into cast and wrought, into heat- treatable and non-heat-treatable significantly depends on the fact that an alloy composition is made by choosing the components with no respect to the external influence on the formation of alloy properties.

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Effect of Heat Treatment on Tribological properties of A356 Reinforced with bottom ash Metal Matrix Particulate Composite

Effect of Heat Treatment on Tribological properties of A356 Reinforced with bottom ash Metal Matrix Particulate Composite

ABSTRACT: The effect of mechanical properties of A356 reinforced with bottom ash after heat treatment was studied in this article. Including the bottom ash reinforcement in the metal matrix displayed furthermore decreased in wear rate and thereby improving the wear resistance. The permanent mould, gravity cast (A356 reinforced with bottom ash) alloys obtained from stir casting were heat treated for varied heat treatment parameters such as solutionising, and natural ageing, which spurred further improvement in the microstructure and the mechanical properties. The precipitation increased the hardness of the alloy/composite proportional to the solutionising temperature and natural ageing was found to enhance the hardness. Therefore, effect of heat treatment variables viz, bottom ash reinforced A356 alloys/composites has resulted in a more wear resistant material with improved mechanical properties. In case of MMC’s, aluminum matrix composite due their high strength to weight ratio, low cost and high wear resistance are widely manufactured and used in structural applications along with aerospace and automobile industry. Also a uncomplicated and cost effective process for manufacturing of the composites is very necessary for expanding their application. Reinforcements like particulate alumina, silicon carbide, graphite, fly ash and bottom ash etc can easily be incorporated in the melt using cheap and widely available stir casting method.
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Microstructural Study of Heat Treated Chromium Alloyed Grey Cast Iron

Microstructural Study of Heat Treated Chromium Alloyed Grey Cast Iron

Three sets of ten samples each having chromium contents of 0.5, 1.5 and 2.5% were heat treated above the upper critical temperature, to austenitizing temperatures (800 o C, 850 o C, 900 o C) for one hour each and then annealed, normalized and water quenched. Metallographic analyses of the heat treated samples were done. The results showed carbides content increased with increasing Chromium addition.

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Mechanical Properties and Microstructures of Locally Produced Aluminium Bronze Alloy

Mechanical Properties and Microstructures of Locally Produced Aluminium Bronze Alloy

desirable and causes brittleness; slow cooling brittleness- 3% iron and 3% nickel were considered most suitable [10]. This dual phase aluminium bronzes can be worked or heat treated to obtain optimal strength and ductility [11]. During equilibrium cooling of aluminium bronze alloy with 10% aluminium, α-aluminium bronze precipi- tates from β-aluminium bronze phases below 930˚C [12]. In marine environment, the requirements for marine component are, among others, high strength to weight ratio, good castability, and tolerance of local working for repairing damage sustained during service which narrow our choice of alloy to aluminium bronzes. Which thus serves as our basis for this research work: to develop a (α + β)/(α + γ 2 ) phase aluminium bronze with a view to
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Electrical resistivity of additively manufactured AlSi10Mg
for use in electric motors

Electrical resistivity of additively manufactured AlSi10Mg for use in electric motors

To establish the grain and microstructure of the same 5mm test cubes, optical micrographs were compared. All images in Figure 3 were taken under the same light and camera settings. Melt pool boundaries can be clearly seen in the as-built samples as elongated ellipses in the XY (top) plane and as trough-like features in the YZ (side) plane. Annealed sections still show some of the boundaries of the original melt pools but are fainter and more difficult to see. The T6-like heat treated samples do not show any discernible boundaries and are homogeneous in appearance. This suggests that there is a difference between the samples, and any variances between measured resistivity can be attributed to these observed differences.
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Joining Vacuum High Pressure Die Cast Aluminum Alloy A356 Subjected to Heat Treatment to Wrought Alloy 6061

Joining Vacuum High Pressure Die Cast Aluminum Alloy A356 Subjected to Heat Treatment to Wrought Alloy 6061

Currently, there are three major types of aluminum alloys, i.e., Al-Si-Cu, Al-Mg and Al-Si-Mg alloys used for die casting [3]. One of the most widely used conventional high pressure die casting(C-HPDC) aluminum alloys, named A356 is in the Al-Si-Mg group, which possesses excellent die castability, weldability, high ductility and strengths (UTS: 221 MPa, YS: 136 MPa) [4]. Meanwhile, wrought 6061 aluminum alloy has applied in this experiment, which is a precipitation hardening aluminium alloy, containing magnesium and silicon as its major alloying elements. It also has good weldability and strengths (UTS: 190 MPa, YS: 70 MPa) [5]. To improve the mechanical properties, such as UTS and YS, casting are often subjected to a T4, T5 and T6 heat treatment to achieve the required mechanical properties although the application of heat treatments adds extra costs to castings, particularly high for large castings and makes them less competitive despite of property enhancement.
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STUDIES OF HEAT-INDUCIBLE Λ PHAGE. III. MUTATIONS IN CISTRON N AFFECTING HEAT INDUCTION

STUDIES OF HEAT-INDUCIBLE Λ PHAGE. III. MUTATIONS IN CISTRON N AFFECTING HEAT INDUCTION

It has been shown that after the addition of h+, which produces a heat-stable CI product, a lysogen containing a heat-inducible prophage rapidly becomes resistant to heat in[r]

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Effect of Heat Treatment on the Damping Capacity of Austempered Ductile Cast Iron

Effect of Heat Treatment on the Damping Capacity of Austempered Ductile Cast Iron

austempered ductile cast iron to exhibit plastic flow in the interface between graphite and bainite microstructures, which consequently results in a drastically reduced damping capacity. In addition, although the damping capacity depends on the bainite microstructure, we did not observe a significant change in the damping capacity as the austempering treat- ment temperature was increased. This result suggests that the damping capacity did not significantly depend on the type of bainite microstructures obtained by various austempering treatment temperatures and the retained austenite micro- structure in austempered ductile cast iron. 13) Figure 7 shows the effect of the austempering treatment time (austempering temperature = 673 K) on the damping capacity in austem- pered ductile cast iron. It can be seen that the damping capacity did not significantly change as the austempering treatment time increased, indicating that the damping capacity of austempered ductile cast iron depends on the bainite microstructure, but not on the shape of the bainite microstructure and the retained austenite microstructure in austempered ductile cast iron.
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