Lost-wax Research Articles

Inlet shape optimization of pneumobile engine pneumatic cylinder using CFD analysis

The aim of this study is to minimize minor losses in cap-end ports of a pneumatic cylinder used in pneumobil vehicle engine. Six geometry arrangements of intake ports, including the currently used version, were designed assuming conventional machining technology. Boundary conditions for the analysis were acquired from experimental measurement. The air flow was analyzed by 3D stationary CFD analysis in ANSYS Fluent for all designs. Pressure drop was used as the evaluation criteria. Two best configurations according to the obtained results were optimized using ANSYS Fluent Adjoint Solver. The pressure drop was reduced by 81.1% using this method. The obtained results will be used for design of solid geometry customized for production by lost wax casting process.

Høj Stene – en monumental skibssætning ved Gudenåen

Høj Stene – en monumental skibssætning ved Gudenåen

SLS TECHNIQUE FOR FABRICATION OF CAST PARTIAL DENTURE

One of the ancient and common method for rehabilitation of Bilateral end saddle cases is by Removable Partial Denture (RPD)-The framework of cast partial denture (CPD) made by lost wax technique can have many manual/lab errors. To minimize the errors and save time selective laser sintering (SLS) can be used as a method for framework fabrication and designing can be done by computer assisted designing (CAD) method. This a case report of 38 year old female with Kennedy's class 2 CPD was planned for the rehabilitation and framework was fabricated using SLS method. The framework fabricated had clinically better t.

A comparison of the passive fit of a 3-unit implant-supported fixed partial denture fabricated by lost-wax casting, milling soft metal blocks, or direct metal laser sintering: An in vitro study

Statement of problemStresses induced by implant-supported prostheses are related to mechanical complications. However, how the manufacturing method affects the generated stresses is unclear. PurposeThe purpose of this in vitro study was to compare the passive fit of 3-unit cobalt-chromium partial prostheses fabricated by using 3 different methods: conventional casting (milled resin with lost-wax method), machined (milling soft metal blocks), or sintered (direct metal laser sintering). Material and methodsThirty 3-unit implant-supported cobalt-chromium fixed prostheses were fabricated, 10 with each method. Four strain gauges were placed over an in vitro resin model with 2 implants in it; 2 gauges were placed above and 2 on the sides to measure the microdeformations caused by placing the structures above the implants in longitudinal flexion, vertical flexion, or torsion, before and after tightening the screws. An inferential analysis was carried out by using a statistical software program, and the Wilcoxon and Kruskal-Wallis tests were applied and then complemented with the Mann-Whitney test for multiple comparisons with the Bonferroni correction (α=.01). ResultsThe mean longitudinal deformation, vertical flexion, and torsional deformation values increased after tightening the screws with each of the 3 fabrication methods. Significant differences (P<.01) were found for all 3 methods before and after screw tightening. After screw tightening, the machined structures, followed by sintered structures, and the cast structures (P<.05) had smaller deformations in the X, Y, and Z dimensions. The longitudinal deformation was less in machined structures, and vertical flexion deformation was less in machined and sintered structures than in cast structures (P<.05). ConclusionsThe deformations registered in the in vitro model increase considerably after screw tightening, which indicates the lack of passive fit. Machined structures provide a better passive fit, followed by sintered structures, and the cast structures had the poorest fit.

Research on the Inherited Casting Technique of Bronze Drums in China and Southeast Asia

Bronze drums are historical relics that were invented by ancient ethnic groups in Southern China and Southeast Asia. So far, many ethnic groups living in the Mekong River Basin and Hongshui River Basin continue to use bronze drums. However, the bronze drums in the two regions are very different. The ethnic groups living in the Hongshui River Basin attach great importance to the sound of bronze drums. After many experiments in the academic community and the efforts of folk drum casters, many bronze drum casting workshops sprang up in the Hongshui River Basin, among which Brothers Wei’s bronze drum factory successfully cast a variety of sizes of Heger IV bronze drums using the sand mold method. The ethnic groups living in the Mekong River Basin attach great importance to the sculpture of bronze drums. The Heger III bronze drums that they use are the only drums cast using the lost wax method.

Effect of Heat Treatment on the As-Cast Microstructure and Hardness of NiSi3B2 Alloy

Cast Ni-Si-B alloys have the potential for high-temperature applications because of their high resistance to wear, impact, corrosion, and oxidation at elevated temperatures due to an appropriate balance of hard phases and austenite that ensures a good compromise between toughness and hardness. In this work, NiSi3B2 specimens, fabricated by the lost-wax casting process, were investigated. Given the complex multiphase cast microstructure, a differential scanning calorimeter (DSC-TGA) analysis was employed to characterize the reactions that occur during solidification and the resulting phases were characterized using scanning electron microscopy (SEM), with energy-dispersive microanalysis (EDS) and backscattered electron (BSE) image and X-ray diffraction (XRD). Due to the presence of hard phases, machining of the Ni-Si-B components can pose additional difficulties. Therefore, the conditions of the solution heat treatment, which might lead to the homogenization of the microstructure, consequently improving its machinability, were also investigated. The results of the heat-treated samples indicated that the dissolution of the eutectic constituent is accompanied by a significant decrease in the hardness (approximately 17%). It is important to emphasize that the solution heat treatments carried out reduced the hardness without affecting the percentage of borides, which will allow improving the machinability without adversely affecting the alloy performance in service.

Physical reconstruction and mechanical behavior of fractured rock masses

Physical modeling of rock masses containing complex fracture geometries is an important but very challenging task in rock mechanics and rock engineering. In this work, a novel integration of 3D printing and water-soluble casting is presented for the preparation of rock-model specimens with fracture networks, which is similar to the lost-wax casting process. The fracture network is created with water-soluble polyvinyl alcohol (PVA) material by 3D printing. The intact rock matrix is prepared with cement paste. Uniaxial compressive tests combined with the digital image correlation (DIC) technique are conducted to investigate the mechanical properties and failure process of the prepared rock-model specimens. The differentiation rate of the effective variance is defined to recognize the precursory anomalies during the loading process. The mechanical anisotropy is further investigated by a series of rotated models. The results show that the proposed methodology has distinct advantages for replicating rocks with complex fracture geometries in terms of high accuracy for fabricating fracture networks, high repeatability of mechanical properties, and high strength and brittleness of rock matrices. Due to the presence of complex fracture geometries, the nonlinear mechanical responses of the fractured rock-model specimens, including strain-softening and anisotropy, are observed in our experiments.

Technique and technology of Scythian bronze arrowhead casting: Experimental and metallographic approach

The most ubiquitous category of Scythian material culture – the bronze arrowheads – is paradoxically the least studied to date. First and foremost, this concerns one question: how were they cast? No definitive conclusions regarding the technology of arrowhead casting have been reached. Some sources suggest the use of a metal mould for this purpose, while others propose the use of lost-wax casting technique. Our understanding of the casting technology is fundamental since it affected the organisation of the manufacturing process of this important category of material and, as a consequence, the supply of Scythian warriors with necessary weapons. In order to solve this problem, several experiments were carried out casting the arrowheads in a metal mould, using metal moulds to obtain wax models, and lost-wax casting. Comparative metallographic analyses were carried out on the original Scythian arrowheads and their experimental analogues, cast in different ways. The results of the experiments indicate that lost-wax technique was the most likely method used for the casting of Scythian arrowheads. These data were confirmed by the results of metallographic analyses: the difference in the cooling rate of the crystallisation of arrowheads obtained by different casting methods affected the parameters of the crystal structure of their alloy.

Investigation of Conventional vs Nonoriginal CAD/CAM Bars with Production Stage Differences: An In Vitro Precision Study Using a Novel Technique.

The aim of this study was to evaluate the precision of fit of bar frameworks fabricated using three different production processes and the effect of changes in the CAD/CAM process steps on the precision of the resulting bar frameworks. Four implants were applied to a mandibular phantom model, and three different production techniques were used to fabricate 30 bar frameworks. In the first group, the bar frameworks were fabricated with the conventional production process (the lost-wax technique; n = 10). In the second group, a CAD/CAM production process was used with digital data collected individually from the master model for the production of each of the final bar specimens (n = 10). In the third group, a CAD/CAM production process was used with the master model being scanned once, and the single resulting data value was used for the production of all final bar specimens (n = 10). The marginal gap between bar frameworks and implants was digitally calculated (ATOS So High-End 3D Digitizer for Small Objects, GOM Inspect). Newman-Keuls multiple comparison tests, a Tukey multiple comparison test, and Pearson correlation tests were applied to the data with a level of significance of P < .05. The mean marginal gap value of group 1 was 95.25 ± 76.15 μm, which was statistically significantly lower than the other groups (P = .0001). For group 2, the mean marginal gap value was 152.00 ± 97.19 μm, whereas for group 3, the mean marginal gap value was 156.7 ± 78.70 μm. Among group 2 and group 3, no statistically significant difference was observed at the mean marginal gap value. The marginal gap values in the CAD/CAM bar framework groups were significantly higher than the conventional bar framework group. Among the CAD/CAM groups, the mean marginal gap values were not statistically significant.

Effects of build orientation on adaptation of casting patterns for three-unit partial fixed dental prostheses fabricated by using digital light projection

Statement of problemThe lost-wax technique is commonly used for fabricating partial fixed dental prostheses. The casting patterns can be fabricated by using vat photopolymerization (a type of additive manufacturing), but the adaptation of these casting patterns has not been elucidated. PurposeThe purpose of this in vitro study was to evaluate the effect of build orientation on the adaptation of casting patterns fabricated by digital light projection (DLP). Material and methodsA 3-unit partial fixed dental prosthesis with mandibular left second premolar and second molar abutment teeth was scanned and virtually designed with a computer-aided design software program. The cement space was designed to be 30 μm. Specimens were fabricated with 3 build orientations: 0 degrees (with the occlusal surface parallel to the platform), 30 degrees, and 45 degrees (by rotating the file along the long axis). The casting patterns were fabricated by using DLP (Cara Print 4.0) with a photopolymerizable monomer (dima Print Cast Q). Photopolymerization, cleaning, and postpolymerization processes were performed according to the manufacturer’s instructions. The adaptation of the specimens was examined by using a silicone replica method. The vertical marginal discrepancy and axial wall, occlusal, and marginal gaps were measured by using a digital measuring microscope. The effect of build orientation at each cross-sectional area was statistically analyzed by using the Kruskal-Wallis test followed by the pairwise Wilcoxon rank sum test with Bonferroni correction (α=.05). ResultsExcess polymerized resin was observed along the intaglio buccal wall at build orientations of 30 degrees and 45 degrees. Vertical marginal discrepancies in the buccolingual section ranged from −50 to 248 μm, while those in the mesiodistal section ranged from −25 to 182 μm. The gaps in the buccolingual section ranged from 0 to 236 μm, while those in the mesiodistal section ranged from 0 to 177 μm. According to the observation of vertical marginal discrepancies and gaps, the 30-degree specimens inclined during insertion, and the 45-degree specimens were not completely seated. However, the marginal gaps of the 0- and 30-degree specimens were within the clinically acceptable limit of 120 μm. ConclusionsThe limited data indicated that the build orientation influenced the adaptation of casting patterns for 3-unit partial fixed dental prostheses fabricated by using DLP. A build orientation of 0 degrees is recommended for fabricating casting patterns for 3-unit partial fixed dental prostheses because no excess polymerization of the intaglio buccal wall was observed.

Effect of layer thickness on the flexural strength of multiple-unit laser-sintered metal frameworks

Statement of problemLaser sintering devices have been increasingly used to fabricate the metal frameworks of metal–ceramic restorations. In the fabrication process, the sintering layer thickness is an important parameter; however, information on how it may affect the flexural strength of metal frameworks remains limited. PurposeThe purpose of this in vitro study was to evaluate the flexural strength of 3-unit and 4-unit cobalt-chromium (Co-Cr) metal frameworks laser sintered with 20-μm, 30-μm, and 40-μm layer thicknesses. Material and methodsThree-unit and 4-unit master metal die models with premolar and molar abutments were prepared through direct metal laser sintering (DMLS). A total of 40 metal frameworks (n=10 for each metal die model) were fabricated by the lost-wax technique (group C, served as the control group) and through DMLS with 20-μm, 30-μm, and 40-μm layer thickness (experimental groups LS20, LS30, and LS40, respectively). Each metal framework was cemented to a master die with a polyvinyl siloxane impression material and then subjected to a 3-point bend test at a crosshead speed of 1 mm/min. The yield force of each metal framework was used to calculate the flexural strength. Data were statistically analyzed by using 1-way ANOVA followed by a Tukey honestly significant difference (HSD) test and an independent-samples t test (α=.05) The microstructure of the fracture surface was evaluated by scanning electron microscopy. ResultsGroup C reported the lowest mean flexural strength (P<.05), whereas group LS20 reported the highest mean flexural strength, although no significant difference (P>.05) in flexural strength was observed among the DMLS groups. The 3-unit metal frameworks exhibited a statistically significant higher mean flexural strength than the 4-unit metal frameworks (P<.05). ConclusionsThe sintering layer thickness did not significantly affect the flexural strength of the laser-sintered metal frameworks. However, the DMLS groups reported a higher mean flexural strength than the cast group.

Effect of Fluid Flow on the Corrosion Performance of as-Cast and Heat-Treated Nickel Aluminum Bronze Alloy (UNS C95800) in Saline Solution

In this work, the corrosion behavior and surface reactivity of as-cast and heat-treated nickel aluminum bronze casting alloy (UNS C95800) in 3.5 wt% NaCl solution is investigated under stagnant and flow conditions. Increasing flow rate conditions are simulated using a rotating disk electrode from 0 to 9000 revolutions per minute (rpm). Optical micrographs confirm the decrease in the phase fraction of corrosion-sensitive β phase in the microstructure of C95800 after annealing, which, in turn, enhances the corrosion resistance of the alloy. Electrochemical studies including open circuit potentiometry, potentiodynamic polarization, and electrochemical impedance spectroscopy are performed to assess the effect of flow rate and heat treatment on the corrosion of samples at 25 and 40 °C in 3.5 wt% NaCl solution. For both as-cast and heat-treated samples, increasing the flow rate (i.e., electrode rotating rate) linearly reduces the corrosion resistance, indicating that the metal dissolution rate is significantly affected by hydrodynamic flow. Increasing the solution temperature negatively impacts the corrosion behavior of the as-cast and heat-treated samples at all flow conditions.

Preliminary Development of Cold Spray Procedures for Nickel Aluminum Bronze Casting Repair

Nickel aluminum bronze (NAB) castings possess favourable combinations of strength and resistance to corrosion, biofouling and cavitation/erosion, and so have long been used in naval applications. Nonetheless, in seawater environments NAB castings are susceptible to selective phase corrosion and so such components periodically require either replacement, which is very costly, or repair. However, repairs involving traditional, high heat input welding operations can lead to distortion and microstructural changes that unacceptably degrade NAB corrosion performance, and so repairs are not commonly performed. In the present work, cold spray is explored as an alternative for NAB (alloy CuAl9Fe5Ni5) repair without excessive distortion or base metal degradation, and preliminary results of its performance reported. Suitable cold spray parameters have been determined using an iterative approach by analyzing deposits in terms of microstructure, porosity and adhesion to the substrate. It is intended that these parameters will later be used to create simulated repairs which can be more thoroughly characterized for strength, toughness and corrosion performance.

Subtractive versus additive indirect manufacturing techniques of digitally designed partial dentures.

PURPOSEThe purpose of this in vitro study was to evaluate the accuracy of digitally designed removable partial denture (RPD) frameworks, constructed by additive and subtractive methods castable resin patterns, using comparative 3D analysis.MATERIALS AND METHODSA Kennedy class III mod. 1 educational maxillary model was used in this study. The cast was scanned after modification, and a removable partial denture framework was digitally designed. Twelve frameworks were constructed. Two groups were defined: Group A: six frameworks were milled with castable resin, then casted by the lost wax technique into Co-Cr frameworks; Group B: six frameworks were printed with castable resin, then casted by the lost wax technique into Co-Cr frameworks. Comparative 3D analysis was used to measure the accuracy of the fabricated frameworks using Geomagic Control X software. Student's t-test was used for comparing data. P value ≤ .05 was considered statistically significant.RESULTSRegarding the accuracy of the occlusal rests, group A (milled) (0.1417 ± 0.0224) showed significantly higher accuracy than group B (printed) (0.02347 ± 0.0221). The same results were found regarding the 3D comparison of the overall accuracy, in which group A (0.1501 ± 0.0205) was significantly more accurate than group B (0.179 ± 0.0137).CONCLUSIONIn indirect fabrication techniques, subtractive manufacturing yields more accurate RPDs than additive manufacturing.

To Evaluate Marginal Fit of Single Implant Supported Metal-Ceramic Crowns Fabricated by Direct Metal Laser Sintering and Lost Wax Technique: An In Vitro Study

To Evaluate Marginal Fit of Single Implant Supported Metal-Ceramic Crowns Fabricated by Direct Metal Laser Sintering and Lost Wax Technique: An In Vitro Study

Evaluation of Surface Micro-hardness and Fracture Toughness of Conventionally Constructed versus CAD/CAM Constructed Denture Base Materials- an In-Vitro Study.

The purpose of the current study was to evaluate surface micro-hardness and fracture toughness of Acetal Resin and Acrylic Resin (PMMA) constructed either by CAD/CAM milling method or by heat polymerized conventional method (lost wax method). Materials and methods: Twenty-eight specimens (fourteen of each material); Acetal Resin and Acrylic Resin were constructed in the form of discs of 2mm thickness and 10mm diameter. Discs were divided equally according to the denture base material into two groups, group I for Acetal Resin and group II for Acrylic Resin (PMMA). Each group was subdivided according to the way of construction into; sub-groups (n=7). Sub-groups Ia and IIa for CAD/CAM milled discs and sub-groups Ib, IIb for conventionally constructed discs. Microhardness was measured on sample surface by digital display Vickers Micro-hardness Tester. Fracture toughness was evaluated by axial loading by the indentation technique. Results: Group I (acetal resin group) recorded statistically significant higher microhardness mean values than group II (acrylic resin group). Moreover, group Ib (injection processed group) recorded statistically significant higher microhardness mean values than group IIb (conventionally processed group). Regarding fracture toughness there was statistically insignificant differences between all groups with higher mean values of group Ia,b (acetal resin groups). Conclusion: CAD/CAM constructed acetal resin and acrylic resin denture base materials presented superior mechanical properties than conventionally constructed ones and expected to be more durable denture bases. Key words: CAD/CAM, Acetal Resin. Acrylic Resin, microhardness, fracture toughness.

ПІДВИЩЕННЯ ЕКСПЛУАТАЦІЙНИХ ВЛАСТИВОСТЕЙ ДЕТАЛЕЙ МАШИН РЕЛЬЄФАМИ ПОВЕРХНІ

The article discusses the direction of improving the operational properties of machine parts by applying regular reliefs to the surface/ Purpose - to develop a model, plan and methodology for experimental studies of regular reliefs and create their classification by purpose and methods of obtaining. The object of research - regular reliefs on the surface of machine parts. The hierarchy of the main factors that affect the profile of reliefs formed by triangular grooves is determined. This is the normal penetration force of a linear indenter, hardness and elongation of the experimental material. The optimization parameter is the groove depth. A mathematical model and research plan have been developed 23. The methodology and devices for conducting experiments are determined. These are hydraulic presses, linear indenters, optical microscopes, microhardness testers, test materials, instruments, and measuring instruments. Materials for research: alloyed and stainless steel, gray and malleable cast irons, bronze and brass, aluminum and titanium alloys. Classifications of reliefs according to the methods of obtaining and destination are developed. Production methods are based on cold plastic deformation and cutting. The basic methods for the study are static methods: the introduction of a dividing element with discrete drawing and a single protrusion of the shaped mandrel during reduction. The dependence of the depth and double angle of the relief groove on the normal force is shown. A new method for obtaining the surface of a part, including the alternation of supporting platforms and grooves is proposed. The method is carried out using machining and subsequent deformation pulling. A distinctive feature of the method is the use of an intermediate elastic sleeve. KEYWORDS: REGULAR RELIEF, COLD PLASTIC DEFORMATION, LINEAR INDUCTOR, SURFACE OF PARTS, COATING, MODEL OF FORMATION OF RELIEF.

СТРАТИГРАФИЧЕСКИЕ НАБЛЮДЕНИЯ НА НЕОЛИТИЧЕСКОЙ СТОЯНКЕ ТАРТАС-1 (БАРАБИНСКАЯ ЛЕСОСТЕПЬ). ХАРАКТЕРИСТИКА ЗАХОРОНЕНИЙ, ПЕРЕРЕЗАЮЩИХ РАННИЙ КУЛЬТУРНЫЙ СЛОЙ ПАМЯТНИКА

Burial complexes dating back from the Neolithic era to the early-developed Bronze Age have been analyzed. The complexes were revealed at the Early Neolithic site of the Tartas-1 area in the Baraba forest-steppe. The site is represented by two housing buildings and a set of special pits intended for fish fermentation. The peculiar dishes, stone and bone tools, as well as the ritual burials of animals (treasure troves/offerings), made it possible to speak about a previously unknown culture of the Neolithic era called the Baraba Neolithic culture. The necropolises of various chronological periods were periodically constructed in the settlement area. The primary aim of the study was to compile the most complete summary of these burials showing the relative chronology of these objects. The Neolithic burial is the earliest. According to the radiocarbon dating, it dates back to the middle of the 5th millennium BC. This date is much later than the set of early dates received at the Neolithic site, the layer of which the burial cuts. The specificity of the burial practice does not allow making direct analogies with the famous Neolithic burial grounds. This may indicate the future identification of a special cultural and chronological layer, which may have occurred in the Neolithic era of this region. One burial is related to the early-developed Bronze Age (the Odinov culture), as evidenced by the specifics of the burial practice and the inventory. The relative chronology of this burial is clearly emphasized by the fact that the grave was cut by the burial of the Andronovo (Fedorovo) culture. The remaining 18 burials belong to the Andronovo (Fedorovo) culture. Two funeral complexes belong to the same period. Two rows of graves are traced; they are located along the edge of the terrace, parallel to each other. Two funeral complexes, in which the grave was surrounded by an intermittent ring-shaped ditch, are integrated in the upper row system. A distinctive feature of this area of the Andronovo cemetery is the presence of children’s and adults’ graves at the same time. Children’s burials are not planographically differentiated. There are both single and collective tombs. The accompanying inventory found in the graves is common to the Andronovo (Fedorovo) complexes; these are ceramic vessels, bronze cast biconical beads, temple rings, sewn plaques, as well as drilled astragali. The investigated funeral complexes include 20 burials and architectural structures (ditches) accompanying individual burials. To varying degrees, these complexes cut the cultural layer of the Neolithic site and have a later chronological position.

A Shooting Experiment with Reconstructed Scythian Arrows and Bows : New Data on the Iron Age Siege at Dédestapolcsány-Verebce-tető

The archaeological research of the last decades revealed that around the beginning of the Middle Iron Age, at the end of the 7th century BC, the territory of Northeast Hungary and Western Slovakia and the eastern part of today’s Czech Republic were hit by an extensive series of attacks. Approximately 20 fortified settlements are known today where bronze arrowheads, found along pristine hillfort walls, bear witness to devastating sieges that occurred almost simultaneously. The most spectacular evidence of the Early Iron Age attack series in the territory of Hungary is the fortified settlement at Dédestapolcsány–Verebce-tető, located at the fringes of the Bükk Mountains. Hundreds of early Scythian-type cast bronze arrowheads have been discovered there, scattered along the northern wall of the defensive earthworks surrounding the inhabitation zone. Recently, as part of a new research project, we have conducted a shooting experiment using reconstructed Scythian-type bows and arrows to obtain additional information about the efficiency of the bows and arrows used in the siege, as well as about the probable progress and details of the event.

Proračun jačine pitinga kod materijala od livenog gvožđa i legura bakra

An attempt is made to predict the pitting strength of cast iron and copper alloy materials from their compressive yield or compressive proof strength for a reliability of 99% at 107 load cycles. The compressive yield or compressive proof strength is related to the tensile strength of ductile cast iron and copper alloy materials by a proportionality factor. Two proportionality factors are used for brittle cast iron materials. The pitting strength formulation incorporates a nominal design factor at 99% reliability which is estimated from a probabilistic model based on the lognormal probability density function. Pitting strength estimates from the predictions are compared with those of American Gear Manufacturers Association (AGMA) estimates and data from other sources. The predicted values for gray cast irons had variances in the range of -11.28% to 25%. Ductile cast iron pitting strength estimates deviated from those of AGMA by -30.28% to 1.73% and 16.76% to 36.34% for Austempered ductile irons. The variances obtained for cast bronze were from 11.17% and 14.73%, but the sample size was small. These variances appear to be reasonable due to the many factors that can influence pitting resistance. Since pitting strength data for many grades of cast iron and copper alloys are not available (especially in the public domain), they may be estimated by the expressions developed in this study for initial design sizing. Also, the pitting strength of new cast iron and copper alloy materials could likewise be estimated for initial design sizing. This will eliminate long and costly contact fatigue testing at the initial design phases, which of course is necessary for design validation.