Thin Casting Research Articles

Improved pore structure characterization and classification of strong diagenesis sandstones by data-mining analytics in Tazhong area, Tarim Basin.

The Silurian system in Tazhong area is characterized by extensive, low-abundance lithological reservoirs with strong diagenesis, resulting in significant heterogeneity. The complex pore structure in this area significantly impacts fluid control, making accurate characterization and classification of pore structures crucial for understanding reservoir properties and their influence on oil and gas distribution. Based on 314 Mercury Injection Capillary Pressure (MICP) samples in combination with core slices and thin casting slices observation, a pipeline of characterization and classification scheme by data-mining analytics of strong diagenesis sandstone pore structure types in the study zone is established, and the characteristics of different pore structures are clarified. According to the pore structure parameter abstracted by MICP data compression and variable analysis based on hierarchical clustering and principal component analysis (PCA) analysis, the variables are reasonably evaluated and screened, and the screened variables can be divided into three groups: mean pore throat radius-maximum pore throat radius-median pore throat radius-pore throat diameter mean variable group, microscopic mean coefficient variable group, and median pressure displacement pressure-relative sorting coefficient variable group. The combination of classification schemes analysed by decision tree model and linear discriminant analysis (LDA) model was determined. In the two-dimensional projection diagram of LDA model, a relatively obvious distribution of low displacement pressure, middle displacement pressure and high displacement pressure was obtained, and three distribution lines were nearly parallel. Based on the relevant information, 6 combined classification schemes suitable for final pore structure modelling were determined verified by microscopic observation. The correct characterization and classification of pore structure can be applied to the prediction of pore type, which can be used to improve the prediction of oil and gas distribution and oil and gas recovery in the future.

The Micro-Occurrence Mechanisms of Tight Oil: Fluid–Rock Interactions at Microscale Pores, Nanoscale Pores, and Mineral Surfaces

Understanding the micro-occurrence mechanism of tight oil has long been a daunting challenge in the exploration and development of unconventional resources. This article discusses the micro-occurrence mechanism of tight oil through continuous extraction by combining thin casting, fluorescent thin sections, environmental scanning electron microscope observations, physical property testing, and X-ray diffraction experiments. The results indicated that in the tight sandstone of the Chang 8 Formation in the Ordos Basin, the average tight oil content was 35.46% for microscale pores, 35.74% for nanoscale pores, and 28.79% for mineral surfaces. Six types of micro-occurrence states of tight oil were identified: emulsion, cluster, throat, star-like, isolation, and thin film forms. Although clay minerals and heavy components dominate the adsorption of tight oil on mineral surfaces, micro-occurrence is fundamentally an oil–rock interaction process. Hence, oil–rock interactions and occurrence states were combined in this study to identify tight oil’s micro-occurrence mechanism. The van der Waals forces of attraction between asphaltene molecules and a mineral surface play a critical role, and minerals with hydroxyl groups can also combine with carboxyl and hydroxyl groups present in tight oil. As a consequence of the adsorption of heavy components by minerals, tight oil components remain in microscale and nanoscale pores with a higher saturation, increased aromatic hydrocarbon content, and greater fluidity. The heterogeneity of the components due to adsorption influences the physical properties and mineralization framework of tight oil reservoirs. These findings suggest that tight oil occurrence results from the coupling of microscopic occurrence and component heterogeneity in microscale and nanoscale pores.

Reservoir Physical Properties and Micropore Nanocharacteristics of Cores in the Shihezi Formation, Sudong District, Sulige Gas Field, Ordos Basin.

Sulige gas field is a very complex large-scale gas field with low porosity, low permeability, low abundance, and strong heterogeneity. In this study, the nanopore structure of the reservoir in the study area was analyzed. The analysis of reservoir physical properties and core microscopic pore characteristics of Shihezi formation in Sudong District, Sulige gas field, Ordos Basin, was put forward. According to core observation, thin section identification, and grain size analysis, the lithology of gas reservoirs in Shan-1 member and He-8 member in the study area is mainly lithic sandstone, lithic quartz sandstone, and quartz sandstone. According to the analysis of physical data in the study area, the reservoirs in Shan-1 member and He-8 member have typical characteristics of low porosity and low permeability. According to that microscopic observation of sandstone thin section and cast thin section combined with the analysis of scan electron microscope, the results show that both Shan-1 member and He-8 member of Sudong area 2 in Sulige gas field are dominated by class I reservoirs and class II reservoirs. Especially, class I reservoirs are widely distributed, with the cumulative area of this type of reservoirs accounting for 70.12% of the total area in Shan section and 64.12% in He-8 section. Class I reservoirs are scattered in the study area, accounting for 0.27% of the total area in the mountain section and 0.36% in the He-8 section. Class IV reservoirs are distributed dispersedly and have a small distribution area. The cumulative area of reservoirs in mountain section accounts for 5.38% of the total area and that in He-8 section accounts for 5.46%. Therefore, Sudong area 2 in Sulige gas field is a typical low porosity and low permeability reservoir. On the basis of geological background, sedimentary microfacies, diagenesis, and pore structure characteristics of the study area, it is considered that the pore structure of sandstone in the study area is mainly controlled by sedimentary characteristics and diagenesis of sandstone.

Microstructure and Mechanical Properties of Vacuum Centrifugal Casted Ti-6Al-4V Alloy by Casting and Heat Treatment

The Ti-6Al-4V alloy has been widely used for structural materials due to high specific strength property, however it is difficult to cast because of high reactivity at high temperature. In this study casting characteristics and post-casting heat treatment were studied in the cast Ti alloy. The cast alloy was prepared using high-frequency induction heating and horizontal vacuum centrifugal casting to reduce reaction with crucible and mold by minimizing overheating of the molten metal and casting fast. In the thin casting with a thickness of 2 mm, α’ martensite was observed, and in the casting with a thickness of 4~8 mm, α+β Widmanstätten was observed. As the thickness of the casting increased, the grain size, α-lath width, and α-case thickness increased. Accordingly, as the thickness of the casting increased, the hardness of the matrix decreased and the hardness of the surface increased. In addition, when the casting was heat treated below the β-phase transformation temperature, the α-lath width increased, and when quenched after heat treatment in the β-phase transformation temperature region, an α’ martensite was formed. On the other hand, when the casting was heat treated in the atmosphere, it was confirmed that the elongation was very low because hydrogen and oxygen in the atmosphere were induced. In addition it was confirmed that casting defects can be removed through HIP.

Failure analysis of thin cast A357-T6 centre shell induced by casting defect

Thin-walled Al-Si alloy precision casting components are used for various applications due to their excellent castability, corrosion resistance as well as high strength to weight ratio. It is very difficult to achieve all the set requirements due to complexity of thin-walled components through casting processes usually used in producing the aluminium alloy castings. A thin-walled shell, used as a housing unit for a component manufactured from A357-T6 alloy, failed prematurely during a torqueing process. The failed component was subjected to chemical analysis, microstructural analysis, visual examination and mechanical testing to identify the nature of the fracture and establish the primary cause of the failure. In the investigation, optical and electron microscopy, hardness and tensile tests were used to study the fracture. The examined fractured surface of the component revealed that, the fracture occurred in a brittle manner. The dominant and leading casting defect identified in the failed shell is porosity. The analysis of the results indicates that coarser grains and porosity defects led to decrease in ductility and thereby causing the shell to fail in a brittle manner.

Ce-Bearing FeSi Alloy Inoculation of Electrically Melted, Low Sulphur Grey Cast Irons for Thin Wall Castings

Electrically melted and over-heated (>1500 °C) grey cast iron at less than 0.04%S, as commonly used, solidifies large amounts of carbides and/or undercooled graphite, especially in thin wall castings; this is necessary to achieve a stronger inoculation. The efficiency of Ce-bearing FeSi alloy is tested for lower ladle addition rates (0.15 and 0.25 wt.%), compared to the base and conventional inoculated iron (Ba,Ca-bearing FeSi alloy). The present work explores chill and associated structures in hypoeutectic grey iron (3.6–3.8%CE, 0.02%S, (%Mn) × (%S) = 0.013–0.016, Alres < 0.002%), in wedge castings W1, W2 and W3 (ASTM A 367, furan resin sand mould), at a lower cooling modulus (1.1–3.5 mm) that is typically used to control the quality of thin wall iron castings. Relatively clear and total chill well correlated with the standard thermal (cooling curve) analysis parameters and structural characteristics in wedge castings, at different wall thickness, displayed as the carbides/graphite ratio and presence of undercooled graphite morphologies. The difference in effects of the two inoculants addition is seen as the ability to decrease the amount of carbides and undercooled graphite, with Ce-bearing FeSi alloy outperforming the conventional inoculant, especially as the wall thickness decreased. It appears that Ce-bearing FeSi alloy could be a solution for low sulphur, electric melt, thin wall iron castings production.

Quantitative characterization method for microscopic heterogeneity in tight sandstone

Understanding the microheterogeneity of tight sandstone is the basis of reservoir science, and quantitative characterization of the reservoir’s microheterogeneity is key to reservoir evaluation. In this study, an image-processing analysis method to study the heterogeneity of tight reservoirs is established. A modified Image J plugin is used to accurately identify the surface porosity of a thin casting sheet; the heterogeneity of the microscopic pores in a reservoir is then abstracted into discrete values of the surface porosity. A new parameter for quantitative characterization of the microscopic heterogeneity of tight sandstone, that is, the heterogeneity index Q, is proposed. The fractal dimension calculated via a liquid nitrogen adsorption experiment is used to test the new parameter, and the geological significance of Q is discussed. The results show that Q has a good positive correlation with the fractal dimension, which is beneficial in determining the heterogeneity of the reservoir, pore throat distribution, and roughness of the pore surface. Q has a good correlation with physical parameters such as the specific surface area, average pore diameter, and total pore volume of the sample, indicating that this index can effectively characterize and quantitatively evaluate the reservoir. Therefore, this parameter provides a new basis for reservoir evaluation and classification and provides a new direction for delineating advantageous horizons as well as guiding development and mining.

Fluidity of Al-Si Alloy in Metal Mold Casting under Vibration

The effect of mechanical vibration on the metal fallibility in thin casting was investigated in this study. The vibration was applied in vertical and horizontal mode during solidification process of aluminum alloy (Al-12%Si). This was done in the frequency range from (0 to 60) Hz and at two intensities; high intensity at (1.6 Volt, 4Ampere) and low intensity at (0.8 Volt, 2 Ampere). The results indicated that in vertical mode the mechanical vibrations increasingly improve fluidity of thin sections and the maximum percentage of fluidity improvement was equaling to 30.61% at 60 Hz. For horizontal mode it was found that fluidity also increase with frequency and the percentage of improvement was equaling to 33.35% at 12 Hz but then it falls at 60 Hz for both intensities, that because at strong vibration castings have an elliptical form rather than circular due to metal flow in the direction of vibration more than the other directions which mean that horizontal mode can operate most effectively at low frequencies only.

Reservoir characteristics of Chang 2 Member of Yanchang Formation in Area A, Ordos Basin

With the continuous enhancement of exploration and development in the Ordos Basin, in-depth research has been carried out on the petrological and reservoir characteristics of Chang 2 reservoir in Area A, which provides a geological basis for the efficient development of oil reservoirs. Comprehensive use of reservoir sandstone thin section identification casting analysis, mercury intrusion analysis, logging analysis and other methods to systematically study the petrological characteristics, pore characteristics and reservoir physical properties of Chang 2 reservoir in Area A. The results show that the reservoirs in the study area are dominated by fine-grained sandstones, with low component maturity and high structural maturity. They are all medium-low porosity, low-permeability and ultra-low permeability reservoirs. Primary intergranular pores and residual intergranular pores are developed, the reservoir drainage pressure is low, which is good-medium, and the mercury removal efficiency is high, indicating that the reservoir has good storage performance and seepage properties.

Semi-Solid Rheological Squeeze Casting Process of ZL114A Aluminum Alloy Thin-Wall Complex Casting

High-strength aluminum alloy with large-scale and thin-walled complex castings have broad application prospects in aerospace, weapons, electronics, defense and military industries. However, due to the uneven thickness of the plate, the casting defects are inevitable by the ordinary casting method, and it is impossible to accurately control the shape and performance of the casting in the casting process. Previous studies have found that the semi-solid rheological extrusion casting technology with short process and near-end type can help solve this technical problem. Therefore, this paper studies the semi-solid rheological extrusion casting process of thin-walled complex casting of ZL114A aluminum alloy. The combination of numerical simulation and experimental research is used to simulate and optimize the filling and solidification process of thin-walled specimens. Based on this, a semi-solid rheological extrusion casting test was conducted. The result showed that, (1) The optimized model can well reflect the filling and solidification process under different rheological extrusion casting parameters, and obtain defect-free castings through process optimization. (2) The thin-walled parts of the thin plate casting produced by semi-solid rheology extrusion have excellent mechanical property and ductility.

Influence of welding parameters on morphology and mechanical performance of friction spot pressure welded thin monomer cast nylon 6 sheets

In this paper, 1-mm-thickness monomer cast nylon 6 sheets were joined under the pressure and the frictional heat generated between the pinless tool and thin stainless steel plates, which was named friction spot pressure welding technology. Influences of welding parameters on spot weld diameter, morphology, and mechanical performance were investigated. Results showed that incomplete interfacial bonding was observed under insufficient plunge depth. Increased rotational speed, plunge depth, and dwell time caused severer extrusion ring and reticular cracks on the joint surface. Material overheating occurred under rotational speed of 1000 rpm and material adhesion on the back of steel plate happened under plunge depth of 0.25 mm. The weld-bonded area diameter increased with larger welding parameters, but the corresponding joint fracture loads increased and then decreased. Four failure modes including lap interface tearing (IT), upper sheet fracture (UF), outer bonding area separation (BS), and the mixed UF and BS were observed. Spot welds failed with UF possessed the maximum tensile load while joints fractured with IT showed low performance. Three different morphologies were observed on the fracture surface of the IT joints while the fracture surfaces of the joints failed with other fracture modes showed elongated strips and flocculent structures.

Study on solid state steelmaking from thin cast iron sheets through decarburization in H2O–H2

ABSTRACT To study the decarburization behavior of cast iron sheets, a series of gas-solid experiments were carried out. The treatment was carried out under Ar-H2-H2O mixed gas atmosphere. Results show that P H2O/P H2 in the gas mixture determines the oxidation of iron at a given temperature and the critical value of P H2O/P H2 to produce ferric oxide rises with temperature. The oxidation of iron take place when the ratio of P H2O/P H2 > 0.62, 0.66, 0.7 at 1293 K, 1353 K, 1413 K, respectively. The gas-solid decarburization reaction of cast iron sheets follows first-order kinetics. Cross-sectional microstructure images indicate that graphitization of cast iron sheets occurs at 1353 and 1413 K. The depth of the decarburized layer increases gradually with temperature and time, the square of depth has a near linear relationship with time. The activation energies of the decarburization reaction calculated by two different ways are similar to that for internal carbon diffusion.

Presentation and management of postcircumcision meatal stenosis at Hawari Center, Benghazi, Libya: A clinical review of 86 cases

Abstract Background: Circumcision is a commonly practiced surgical procedure particularly in Islamic countries. As any other surgical procedure, it is attended by some complications of either early (e.g., bleeding) or late (e.g., meatal stenosis [MS]). Objectives: This study was designed to study the different clinical pictures, age at presentation, and management and outcome of postcircumcision MS. Patients and Methods: This is a retrospective study involving 86 children diagnosed with symptomatic MS and underwent meatotomy during the period from January 2010 to December 2018 at Hawari Center for Urology and Otolaryngology, Benghazi. The medical records of the patients reviewed included age at presentation, different clinical pictures, management, and outcomes. All patients were circumcised during the neonatal or infancy period. Results: Patients' age ranged between 3 and 13 years with a mean age of 5.14 years. More than three-quarters of the patients (84.8%) were between 3 and 8 years of age. Forty-six patients (53.4%) presented with pain (burning) during micturition; 17 patients (19.7%) with thin casting stream; 13 patients (15.11%) with thin dorsally deviated stream; five patients (5.8%) with sudden urge to micturiate; 3 (3.40%) patients with frequency of micturition; and only two patients (2.3%) with prolonged voiding time. All our patients operated by meatotomy as a day case procedure under general anesthesia, and there were no recurrences of MS symptoms in any case during the follow-up period. Conclusion: MS is a frequent late complication of neonatal circumcision; it should be excluded by careful meatal examination in any child who is circumcised particularly at the neonatal or nappy period and presented with abnormal micturition or even lower abdominal pain.

Investigation of Side-Dam Plate in Single-Wheel Caster for Casting Rods

The cross section of a thin rod cast by a single-wheel caster, for which the wheel cross section is an inverted trapezoidal groove, is concave. To make the cross section convex, an inner side-dam plate is proposed. A single-wheel caster with a flat wheel (without a groove) and rotating side-dam plates is also proposed. 5182 aluminum alloy rods with a convex or rectangular cross section can be cast. The area of the rod is smaller than 150 mm2. The diameter of the converted circle area is 15 mm.

Microstructural and Mechanical Characteristics of A356 Alloys as a Function of Mn Content and Cast Thickness.

In this study, the changes in the microstructural characteristics and mechanical properties of A356 alloys as a function of Mn content and cast thickness were evaluated using structural analysis and tensile tests. Five different A356+x%Mn alloys were prepared by casting in molds of different thicknesses followed by solid solution treatment at 813 K for 195 min and aging treatment at 423 K for 120 min. It was confirmed that the secondary dendrite arm spacing (SDAS) increased with increasing thickness of the cast sample, whilst, for a given thickness, the addition of small amounts of Mn resulted in a decrease of the SDAS. Mn contents of 0.05-0.15% resulted in ~7-9% improvements in the spheroid ratio of the primary Si particles compared to that of the commercial A356 alloy. Further, the spheroid ratio of the primary Si particles obtained in the thin cast samples were higher than that obtained in the thick cast samples. In particular, the addition of small amounts of Mn was also effective in suppressing the formation of the needle-like beta Al-Fe-Si intermetallic compound. The yield and tensile strengths of the thinner cast samples were higher than those of the thicker cast samples. Finally, Mn contents of 0.05-0.15% resulted in enhanced yield and tensile strengths, but Mn content ≥0.1% resulted in decreased elongation.

Refinement of primary carbides in AISI DC 53 cold work tool steel by thin section copper permanent mould casting and water atomization

ABSTRACTIn this study, as alternative methods to conventional production methods involving thin section copper permanent mould casting (fast solidification) and water atomization (rapid solidification) of AISI DC 53 cold work tool steel have been investigated. Thin slabs obtained by copper mould casting was homogenized at 1150 °C for one hour and then hot rolling was be applied. After hot rolling, conventional heat treatment have been applied to thin slabs. The same heat treatment procedure have been performed for a commercially available AISI DC 53 which is manufactured by thick section ingot casting and rolling. In order to investigate also the effect of rapid solidification on AISI DC 53 tool steel, steel powder was produced by water atomization technique. Experiments have revealed that thin steel slabs in permanent copper mould and rapidly solidified tool steel powder by water atomization have a more refined primary M7C3 carbides than commercially available steel.

Synthesis, Characterization of New Polyamides Bearing Triarylamine for Lightemitting Diodes

In this work, new di-acid monomers 4, 4’-di-carboxillic-4”-bromo-2”, 6”-dimethyl triphenylamine (Ma), 4, 4’- di-carboxylic -4”-chloro-2”, 6”-dimethyl triphenylamine (Mb) and 4, 4’- di-carboxylic -2”,4”-dichloro-6”-methyl triphenylamine (Mc) were synthesized by reaction of p-cyanobenzofluride with three different aromatic amines (4-bromo,2,6-dimethyl aniline, 4-chloro,2,6-dimethyl aniline and 2,4 dichloro, 6- methyl aniline ) via aromatic nucleophilc substitution method to form three di cyano intermediates 4, 4’-Dicyano-4”-bromo-2”, 6”-dimethyl triphenylamine (Da), 4, 4’-dicyano-4”-chloro-2”, 6”-dimethyl triphenylamine (Db) and 4, 4’-dicyano-2”,4”-dichloro-6”-methyl triphenylamine (Dc) which form final di-carboxylic monomers after alkaline hydrolysis. Finally, these monomers react with two different aromatic di amines, phenylene diamins and benzidine respectively via polycondensation reaction to form final polyamides 4"-bromo-2", 6"-dimethyl-triphenylamine-4, 4'-polyphenylbenzamide (Pa), 4”-chloro-2”,6”-dimethyl- triphenylamine-4,4'-polyphenylbenzamide (Pb), 2”,4”-dichloro-6”-methyl-triphenylamine 4,4'- polyphenylbenzamide (Pc),4"-bromo-2",6"-dimethyl triphenylamine-4,4'- polyphenylbiphenylamide (Pd), 2”,4”-dichloro-6”-methyl-triphenylamine-4,4’-polyphenylamide (Pf).
 The chemical structure of these polymers characterized by FTIR and NMR techniques. All the results of polyamides showed excellent solubility in most polar solvents to form strong thin films. The polyamides possess a good thermal stability with height glass transition temperatures (Tg).
 Polyamides in DMSO solvent gave strong photoluminescence PL. Thin casting films of these polyamides in cyclic voltammetry (C.V) on glass base of iridium-tin oxide (ITO) as working electrode in dry CH3CN solvent contains 0.1 M of tetrabutylantimoneperchlorate (TBAP) as an
 Electrolyte gave one redox wave.

Structure Property Correlation of Thin Wall Ductile Iron

This research work concerns an assessment of the effect of one step inoculation method on thin section castings (2-5) mm analyzed. In this study inoculants representing Ce, Zr and Sr bearing Fe-Si alloys were used. It has been observed that section thickness of 2 mm thin plate containing Ce bearing Fe-Si alloys at 0.4wt% contain mainly pearlitic matrix having microhardness (HV20), ultimate tensile strength (UTS) and percentage of elongation are 272 HV, 720 MPa and 4.5% respectively. It was observed that wear of 2 mm section thickness of thin plate containing Ce bearing Fe-Si alloys have greater wear resistance (272HV) compare to Zr bearing Fe-Si alloys (262HV) and Sr bearing Fe-Si alloys (259HV) respectively at 0.4wt% due to reason of pearlitic and ferritic volume fraction contents present in matrix.

A New Approach in Solid State Steelmaking from Thin Cast Iron Sheets through Decarburization in CaCO<sub>3</sub> Pack

A New Approach in Solid State Steelmaking from Thin Cast Iron Sheets through Decarburization in CaCO<sub>3</sub> Pack

超薄肉鋳鉄製羽釜・かまど「内匠」の開発:次世代へ伝えたい「和食；日本人の伝統的な食文化」の担い手として

超薄肉鋳鉄製羽釜・かまど「内匠」の開発:次世代へ伝えたい「和食；日本人の伝統的な食文化」の担い手として