Alloy Cast Steel Research Articles

Scuffing Behavior of 4140 Alloy Steel and Ductile Cast Iron

Scuffing Behavior of 4140 Alloy Steel and Ductile Cast Iron

Assessment of the Low Alloy Cast Steel Inoculation Effects with Chosen Additives

Assessment of the Low Alloy Cast Steel Inoculation Effects with Chosen Additives Structure, and thus the mechanical properties of steel are primarily a function of chemical composition and the solidification process which can be influenced by the application of the inoculation treatment. This effect depends on the modifier used. The article presents the results of studies designed to assess the effects of structural low alloy steel inoculation by selected modifying additives. The study was performed on nine casts modeled with different inoculants, assessment of the procedure impact was based on the macrostructure of made castings. The ratio of surface area equivalent to the axial zone of the crystals and columnar crystals zone was adopted as a measure of the inoculation effect.

The Structure of the Silumin Coat on Alloy Cast Steels

The Structure of the Silumin Coat on Alloy Cast Steels The work presents the analysis results of the structure of the coat obtained by dipping in silumin AlSi5 of two grades of alloy cast steel: GX6CrNiTi18-10 (LH18N9T) and GX39Cr13 (LH14). The temperature of the silumin bath was 750±5°C, and the hold-up time of the cast steel element τ = 180 s. The absolute thickness of the coat obtained in the given conditions was g = 104 μm on cast steel GX6CrNiTi18-10 and g = 132 μm on GX39Cr13. The obtained coat consisted of three layers of different phase structure. The first layer from the base "g1" was constructed of the phase AlFe including Si and alloy additives of the tested cast steel grades: Cr and Ni (GX6CrNiTi18-10) and Cr (GX39Cr13). The second layer "g1" of intermetallic phases AlFe which also contains Si and Cr crystallizes on it. The last, external layer "g2" of the coat consists of the silumin containing the intermetallic phases AlFeSi which additionally can contain alloy additives of the cast steel. It was shown that there were no carbides on the coat of the tested cast steels which are the component of their microstructure, as it took place in the case of the coat on the high speed steels.

The Quality of the Joint Between Alloy Steel and Unalloyed Cast Steel in Bimetallic Layered Castings

In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation. Prepared castings consist two fundamental parts i.e. bearing part and working part (layer). The bearing part of bimetallic layered casting is typical foundry material i.e. ferritic-pearlitic unalloyed cast steel, whereas working part (layer) is plate of austenitic alloy steel sort X2CrNi 18-9. The ratio of thickness between bearing and working part is 8:1. The aim of paper was assessed the quality of the joint between bearing and working part in dependence of pouring temperature and carbon concentration in cast steel. The quality of the joint in bimetallic layered castings was evaluated on the basis of ultrasonic non-destructive testing, structure and microhardness researches.

Key Anti-Friction Technology Breakthrough in Steel Collars: First Using Electro Slag Remelting in the Second Remelting of HSS Collars

This is the first time in the steel industry that the steel mill applies the electro slag remelting to high-tungsten HSS roll collars for the second remelting after centrifugal casting. Such successful innovation in high-tungsten HSS roll collars dramatically enhances the life span of HSS roll collars more than that of ordinary alloy steel cast roll collars. Besides, this technology breakthrough improves the anti-friction bearing of collars and it leads to more efficient and economical advantages. The experiments evidences are presented in this study.

Effect of Modification Powders on Low Alloy Cast Steel

Effects of V-Ti-Zr-Re containing modification powders on the mechanical properties and microstructure of low alloy steel castings by conventional normalizing, hardening and tempering processes and normalizing-free heat treatment were investigated. The results showed that for the as-modified casting, martensite and carbides were the main phases after direct quenching and low-temperature tempering but skipping normalizing. The mechanical properties were almost the same or even higher in impact toughness than the same material but bearing also normalizing treatment. Both samples modified by alloy powders, whether normalizing treated or not, possessed superior mechanical properties to those castings without being modified. The modification technique can be applied in low alloy steel production to eliminate the time and energy consuming normalization process, so that the cheap, energy saving and environment friendly materials are thus expected.

Investigation and application of high strength low alloy wear resistant cast steel

<title/>A kind of low alloy wear resistant cast steel that does not contain costly alloy elements such as molybdenum, nickel, copper and vanadium has been successfully developed. By the refinement with rare earth and titanium, the purification with blowing argon and improving the hardenability with boron, the cast steel containing 0·25-0·45%C, 0·5-1·5%Si, 0·5-1·5%Mn, 0·5-1·5%Cr and a small quantity of titanium, boron, rare earth, calcium and aluminium has high tensile strength, impact and fracture toughness and excellent wear resistance. In the excavator bucket teeth, crusher hammer and ball mill liner, low alloy wear resistant cast steel has 2-4 times longer servicing life than that of Hadfield austenitic steel, and its production cost is equal to that of Hadfield austenitic steel. The use of low alloy wear resistant cast steel is safe and reliable, and there is no fracture and scaling in the use. The application of low alloy wear resistant cast steel has good economic and social benefits.

Analysis of Quenching Crack Generation in Low Alloy Cast Steel by Using Heat Treatment Simulation

Analysis of Quenching Crack Generation in Low Alloy Cast Steel by Using Heat Treatment Simulation

Effects of Specimen Thickness on Quenching Crack in Low Alloy Cast Steel

Effects of Specimen Thickness on Quenching Crack in Low Alloy Cast Steel

Microstructure, mechanical properties and high stress abrasive wear behavior of air-cooled MnCrB cast steels

Three medium carbon low alloyed MnCrB cast steels containing different Cr contents (0.3%, 0.6%, and 1.2%) were designed and the effect of Cr contents on the microstructure, mechanical properties and high stress abrasive wear behavior of the cast steels after 850 °C air-cooling and 220 °C tempering was studied. The results show that the hardenability of the MnCrB cast steels was excellent. The microstructure of the cast steels with low Cr contents (0.3% or 0.6%) consists of granular bainite and lower bainite/martensite multiphase. With increasing of Cr content, the formability of martensite was improved, the hardness and wear-resistance increased, but the impact toughness decreased in that more bainite was replaced by martensite. The air-cooled MnCrB cast steel containing 0.6% Cr, with granular bainite and lower bainite/martensite multiphase, exhibited excellent combination of strength, hardness, ductility, and impact toughness. In addition, its abrasive wear-resistance was 30% more than that of Hadfield cast steel in the high stress abrasive wear condition. This air-cooled MnCrB cast steel by simple alloying scheme and heat treatment has the advantages of high-performance, low cost, and environmentally friendly. It is a potential advanced wear-resistant cast steel for low- or even medium-impact abrasive conditions.

Investigations of Solidification Structures of High Carbon Alloy Cast Steel Containing RE-V-Ti

The solidification microstructural characteristics of rare earth (RE) and vanadium and titanium-treated high carbon alloy cast steel, whose chemical compositions are 0.90 wt.% C, 3.0 wt.% Si, and 1.0 wt.% Mn, were investigated by means of optical microscopy (OM), scanning electron microscopy (SEM), electron probe microanalyzer (EPMA), and energy dispersive X-ray spectrometry (EDS). The alloys were prepared in an induction furnace. The results showed that compound additions of RE-V-Ti could obviously refine the solidification structures and decrease the diameter of grains. The average grain diameter of untreated high carbon alloy cast steel was 80 μm. The average grain diameter of high carbon alloy cast steel containing RE-V-Ti decreased to 40 μm. Finally, the reasons that RE-V-Ti refined the solidification structure were analyzed in detail.

Effect of austempering treatment on microstructure and mechanical properties of high-Si steel

In the present investigation, the influence of austempering treatment on the microstructure and mechanical properties of silicon alloyed cast steel has been evaluated. The experimental results show that an ausferrite structure consisting of bainitic ferrite and retained austenite can be obtained by austempering the silicon alloyed cast steel at different austempering temperature. TEM observation and X-ray analysis confirmed the presence of retained austenite in the microstructure after austempering at 400 °C. The austempered steel has higher strength and ductility compared to as-cast steel. With increasing austempering temperature, the hardness and strength decreased but the percentage of elongation increased. A good combination of strength and ductility has been obtained at an austempering temperature of 400 °C.

Characterization of two friction interfaces for use in seismic damper applications

This paper describes an experimental research program on the friction interface characteristics for a new type of friction damper for use in seismic building applications. Two friction interface types (leaded-bronze against stainless steel and leaded-bronze against alloy cast steel) are subjected to a series of triangular and sinusoidal displacement loading waveforms. The test parameters include the loading frequency, displacement amplitude, number of cycles, and normal force applied on the friction interface. The experiments show that the dampers can provide predictable and consistent levels of energy dissipation that is largely independent of excitation displacement, frequency, and velocity for the ranges expected to occur during an earthquake. The results are used to determine the coefficient of friction for the dampers and to verify an analytical model for friction-damped precast concrete frame buildings.

Effects of Cooling Medium on Quenching Crack in Low Alloy Cast Steel

Effects of Cooling Medium on Quenching Crack in Low Alloy Cast Steel

Reformer tubes: Not a commodity

AbstractAt the heart of the primary reformer are centrifugally cast alloy steel tubes. These tubes experience the extreme conditions required for steam methane reforming and thus require high quality to achieve their expected design life. The tube designs need to balance heat transfer rates, optimize catalyst volumes and minimize thermal stresses, while not compromising the tube life expectancy. Centrifugally cast heat resistant alloys have proven themselves as the ideal material for this service.Individual cast tubes are custom made so it is important that the buyer be aware of the manufacturing methods of these products: to be aware of potential pitfalls and to appropriately specify the inspection and quality assurance requirements. Each tube segment is cast individually from a small heat, resulting in a unique chemical composition. Subsequent boring, machining, welding, and inspection operations are important to ensure the quality of the tube segments and the final reformer tube assembly. The reformer tube manufacturing process, including casting, machining and fabrication, is presented with the typical inspection operation.Some defects in the design and fabrication are described. These defects have caused ammonia and syngas plant shutdowns at a great expense to operating companies. Such defects can be avoided at the design or specification stage or during quality control tests. This paper describes how to avoid such defects. © 2007 American Institute of Chemical Engineers Process Saf Prog, 2007.

熱処理ＣＡＥソフトウェアを活用した低合金鋳鋼材の焼割れ発生シミュレーション

In order to understand the quenching crack phenomenon in cast steel, a disk shaped low alloy cast steel specimen having a opening was quenched in water at 1123K. The behavior of a quench crack was investigated by microstructure observation and analyzed by the Heat treatment CAE software. The results obtained are as follows. (1) The quench cracking easily occured as the volume of specimen increased. The mass effect for quenching crack was significant. (2) The quench cracking was due to time lag in martensitic transformation at surface side and inner side of the quenched specimen, but not due to the thermal stress in the specimen. (3) The behavior of a quenching crack was able to be predicted by the Heat treatment CAE software. (4) Therefore, the Heat treatment CAE software is useful for a counterplan preventing the quenching crack.

AUSTEMPERING OF A SILICON MANGANESE CAST STEEL

The influence of austempering on the microstructure and mechanical properties of an alloyed cast steel containing high silicon (3.00%) and high manganese (2.00%) was studied. The influence of microstructure on the plain strain fracture toughness of this new steel was also examined. The test results show that by using a suitable austempering process, i.e., by austenitizing at 1010°C (1850°F) for 2 hr and then subsequently austempering at 316°C (600°F) for 6 hr, it is possible to produce more than 80% austenite in the matrix of the material. Such a large percentage of austenite in the matrix made the steel almost nonmagnetic. Austempering resulted in a significant improvement in mechanical properties as well as fracture toughness of the material. The potential applications of this steel are in naval structural components, aircraft, and automotive components.

Microstructure and mechanical properties of austempered high silicon cast steel

The influence of austempering treatment on the microstructure and mechanical properties of silicon alloyed cast steel has been studied. The experimental results show that an ausferrite structure consisting of bainitic ferrite and retained austenite can be obtained by austempering the high silicon cast steel in a large temperature range (240–400°C). No carbide would precipitate in the structure. The experimental results also indicate that a full ausferrite structure could be obtained by austempering the steel with a silicon content around 2.64%. Lower silicon would result in the formation of martensite, and excessive silicon would cause proeutectoid ferrite in the structure. The full ausferrite structure has high strength, toughness and hardness. With the increasing of silicon content, the strength decreases, the hardness keeps unchanged and the toughness firstly increases to a maximum value and then decreases. The material has also excellent work hardening ability.

Effect of top and bottom filling on reliability of investment castings in Al, Fe, and Ni based alloys

The effect of bottom and top filling running systems on the properties of four investment cast alloys susceptible to contamination by oxide films during filling was studied. The alloys were air cast 2L99 Al–Si–Mg alloy and 254-SMO super duplex stainless steel and vacuum cast IN939 and IN738LC nickel based superalloys. The Weibull moduli for the tensile strength of investment cast bars produced using top and bottom filling were compared as indicators of casting reliability and of oxide damage produced by the running systems. A Weibull modulus of 18 was obtained for top filled 2L99 castings; this was increased to 34 when a correctly designed bottom filling system with a filter was used, thus reflecting the decreased scatter in properties. However, a similar effect was not found for the stainless steel. The use of improved running system designs led to minor increases in the Weibull modulus of the IN738LC and IN939 Ni alloys.

Studies on grinding media wear and its effect on flotation of ferrugenous phosphate ore

Marked ball grinding tests were carried out in the laboratory with a low grade phosphate ore under different experimental conditions. Two types of balls were used, namely high carbon low alloy (HCLA) cast steel and high chrome cast iron. Results of marked ball grinding tests indicated that ball wear increased with time and showed a sharp increase for wet grinding over dry grinding. Ball wear under wet grinding conditions was also influenced by the gaseous atmosphere in the mill. The grinding ball materials could be arranged in the following order with respect to their overall wear resistance: High chrome cast iron > HCLA cast steel balls Methods to minimize ball wear through control of mill atmosphere and addition of flotation reagents are discussed. Effect of grinding media and additions of flotation reagents during grinding on phosphate ore flotation are also discussed.