bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of Forming Limit Curves for Aerospace Aluminum Alloys
Authors: Hursman TL 
Published: March 2009

The objective was to develop forming limit curve (FLCs),tensile(elastic and plastic) properties, and production stretch-form test data for two alloys.
A laboratory technique developed by Hecker and his associates at General Motors Research Laboratories was used to develop FLCs for 2024-T3 and 2219-T31 aluminum alloys. This laboratory technique involves biaxial punch-stretch testing of sheet metal specimens clamped securely between two die plates at the periphery. Using this technique, the influences of sheet thickness, lubrication, blank size, and blank orientation on forming limits were investigated.
The values of the strain-hardening exponent and plastic strain ratio calculated for 2024-T3 and 2219-T31 aluminum alloys are in good agreement with those for other aluminum alloys reported by Hecker. The strain-hardening exponent, n, was found to be higher for 2219-T31 than for 2024-T3. The average plastic strain ratios, r, for 2024-T3 were higher than for those for 2219-T31 in all three test directions.
All FLCs measured in the laboratory were found to be in good agreement with production stretch-form test data.
Workability Testing and Analysis for Bulk Forming Processes
Authors: Kuhn HA 
Published: March 2009

A workability test procedure has been developed using cylindrical upset tests and bend tests. Variation of the upset specimen aspect ratio (height-to-diameter ratio) and of lubrication of the compression dies produces a variety of stress and strain combinations at the free surface of the cylinders. Bend tests extend the range of available stress and strain states, and are also useful in cases where cylindrical upset test specimens are impractical. In either test, measurements of grid deformations at the surface permit calculation of the surface strains and, with the aid of plasticity equations, surface stresses.
Results show that the surface tensile and compressive strains at fracture fit a straight line relationship having a slope of −½ and an intercept along the tensile strain axis. The intercept depends on material, composition, structure, and surface condition. Such results have been found for a variety of ferrous and nonferrous alloys, as well as sintered powder metals at cold and hot working temperatures.
The fracture-strain relationship determined by workability tests can be used for workability analysis of bulk-forming processes. Progressive strain relationships in critical regions of the workpiece of interest are determined through plasticity analysis or through measurements on model materials. These relationships are compared with the fracture strain relationship to determine the likelihood of defect formation and to suggest alterations of the process for improved workability. This approach has been used for analysis of cracking in various modes of flow generic to forging, such as formation of hubs, flanges, rims, and gear teeth; it has been also applied to specific forged parts.
Zirconium for Nuclear Primary Steam Systems
Authors: Webster RT 
Published: March 2009

Zirconium and zirconium alloys provide the best combination of metallurgical and mechanical properties for light and heavy water nuclear reactor fuel cladding and for the primary steam generation equipment. However, before materials may be used in such applications, long-term mechanical properties within the reactor operating temperature range must be established. Also, fabrication methods for such systems must be developed and evaluated.
In order that zirconium would become a qualified ASME Boiler Code material, a long-term test program was initiated; the qualifying data is presented in graphical form. The statistical data on short-term physical tests is amplified by the long-term creep rate and rupture-life versus temperature data.
Primary steam generation equipment fabrication data and criteria are presented with examples. Examples of the use of zirconium and zirconium alloys in nuclear and non-nuclear structures is reported; the stages necessary to fabricate components for the large nuclear steam generation equipment used in commercial power production is discussed.
Additional data required by international specifications is also presented, including charpy impact and fatigue data, as well as the normal mechanical property tests.
Development of a Closed-End Burst Test Procedure for Zircaloy Tubing
Authors: Hardy DG , Stewart JR , Lowe AL 
Published: March 2009

The results of a round robin on the closed-end burst testing of Zircaloy tubes for fuel cladding are presented. Sponsored by the American Society for Testing and Materials, the testing program had as its objective the preparation of a suitable burst test procedure for inclusion in the ASTM Specification for Wrought Zirconium and Zirconium Alloy Seamless and Welded Tubes for Nuclear Service (B 353-71).
Seventy-five specimens, cut from five lengths of tubing were tested at room temperature. Four laboratories took part and six different test methods were used.
It was found that the closed-end burst test can be used to characterize the biaxial mechanical properties of Zircaloy cladding tubes. The tests identified certain parameters as having a significant effect on the mechanical properties and which must be precisely defined in the specification, these include the internal mandrel geometry, strain rate, and system stored energy. The most desirable burst test apparatus is one which has low stored energy and which provides good control over the volume pumping rate producing a smooth pressure versus fluid volume output curve.
Uniform Ultrasonic Inspection of Fuel Sheath Tubing
Authors: Cross BT , Abbott DJ 
Published: March 2009

Ultrasonic nondestructive inspection of fuel tubing can be made far more uniform and reliable by placing proper priority on the various test parameters. Search units, for example, should be designed specifically for a given tube size, tube material, and quality assurance specification. It is common practice to select a standard product line search unit and juggle test parameters until some semblance of a test is achieved. Through an in-depth study of tubing inspection requirements, it has become evident that arbitrarily selected search units will rarely satisfy the actual requirements for tubing inspection.
“Spectral compatibility” in an ultrasonic inspection system is as important in achieving realistic test results as proper selection of search units. This often ignored parameter is one of the keys to uniform reproducible inspection results.
This paper discusses these significant test parameters, how they are used, and their relation to the current ultrasonic inspection procedures being used in American Society for Testing and Materials Committee B-10 on Reactive and Refractory Metals and Alloys.
Improved Metallography of Zirconium Alloys
Authors: Kaufmann PD , Danielson P , Baroch EF 
Published: March 2009

Several procedures for the metallographic preparation and viewing of zirconium alloys have been developed in recent years which broaden the ability of the metallographer to more totally describe the morphology of these materials. For most detailed studies, it is not possible to describe with a single method the structure of commercial materials. Features found to be present by one technique may be completely missed or inconclusively revealed by other techniques.
Anodizing a metallographically prepared sample of a zirconium alloy in a phosphoric acid solution results in color contrast between retained intermetallic compounds and the matrix. While this method is not new, its application to evaluation of low-solubility compounds is described herein. A color contrast is also observed between various types of intermetallic compounds by the nature of their different anodizing characteristics. A technique for metallographic preparation and anodizing is described. The resultant microstructure with typical carbide, phosphide, and silicide intermetallics in zirconium and zirconium alloys is shown with color photomicrographs. Characteristics of each of these three types of intermetallic compounds are described.
A technique for heat tinting metallographic samples of Zircaloy-2 and Zircaloy-4 to show alloy microsegregation is also described. This method is complementary to anodizing and conventional etching methods. Subtle compositional variations, such as the tin distribution in the Zircaloys, can be revealed by heat tinting techniques. Such variations are not apparent with other techniques.
Potential for Improvement of Mechanical Properties in Zircaloy Cold-Rolled Strip and Sheet
Authors: Kaufmann PD , Baroch EF 
Published: March 2009

A summary of mechanical properties representing several thousand Zircaloy-4 channel blanks is presented. The data show a wide variation in elevated-temperature mechanical properties.
Investigation of the effect of variations in ingot chemistry on mechanical properties is discussed. The effect of the elements carbon, silicon, tin, and oxygen on elevated-temperature yield strength is statistically significant, but does not account for the total magnitude of the variation in mechanical properties observed. Although it does not represent an actual material variation, tensile testing strain rate was found to have a very significant effect on elevated-temperature yield strength values. Further experimental work was performed to investigate the effect of fabrication variables on elevated-temperature yield strength. The most influential processing parameter on elevated-temperature yield strength of the resultant product was the hot-rolling temperature. A 20 to 30 percent variation in yield strength was observed between alpha-rolled and beta-rolled material. This variation existed even after subsequent cold rolling and recrystallization. The primary difference between these two products was shown to be the difference in preferred orientation. The elevated-temperature transverse yield strength and bend ductility were improved by beta rolling, while the product uniformity, corrosion resistance, and tensile elongation were decreased. The limitations as well as potential improvements in mechanical properties which could be obtained through processing variations are discussed.
Operable Deformation Systems and Mechanical Behavior of Textured Zircaloy Tubing
Authors: Tenckhoff E 
Published: March 2009

The slip and twinning systems known to operate in zirconium and Zircaloy are discussed with respect to the mechanical behavior of Zircaloy tubes. For extreme basal pole orientations in the radial and tangential directions, different stress-strain conditions in the tube cause different deformation systems to operate. The effects of the stress-strain conditions are discussed for axial tension and compression, internal and external pressure, axial bending, tube collapse, and axial torsion. The predictions of short time properties for strongly textured radial and tangential tubing are compared with experimental results.
The method of taking tubes from a textured plate has proved suitable for studying texture as a parameter not only in the extreme positions discussed here but also at intermediate positions. This technique guarantees that other parameters, such as the degree of deformation and recrystallization, grain size, segregation, etc., are constant since all the variants of texture are present in one single tube.
Directionality of the Grain Boundary Hydride in Zircaloy-2
Authors: Kawanishi H , Ishino S , Mishima Y 
Published: March 2009

The correlation between hydride orientation and texture has been studjed. Previous_work showed that there are grain boundary “habits” such as {101¯1}, {101¯3}, and {101¯5} for hydride precipitation in Zircaloy-2. By taking into account the stereographic configuration of these habits, the fn-values of various specimens have been evaluated. Comparison between fn-values obtained metallographically and by the present method gives excellent agreement.
The mechanism of stress reorientation of hydride and the dependence of stress reorientation on stress direction are also discussed.
Stress Corrosion Cracking of Zircaloys in Iodine Containing Environments
Authors: Cox B 
Published: March 2009

Iodine solutions in organic solvents fall into two groups. First, those which, like iodine vapor at room temperature, cause crack propagation in double cantilever beam (DCB) specimens but do not initiate cracks in smooth specimens. These are solvents which form no, or only weak complexes with iodine. A second group of solvents (alcohols) both initiate cracking in smooth specimens and cause crack propagation in DCB specimens. These are solvents which form strong complexes with iodine. In addition to these two groups there are a few solvents in which neither crack propagation in DCB specimens nor cracking of smooth specimens occur.
Modifications to the chemistry of the system by additives were effective only for arsenite and N2O additions to alcoholic solvents. In both instances times to failure were increased. These results are discussed in terms of the chemistry of the system, and the mechanisms operating during both crack initiation and propagation are considered.
Correlation Between Corrosion Behavior of Steel and Atmospheric Pollution Data
Authors: Haynie FH , Upham JB 
Published: March 2009

Specimens of an enameling steel were exposed at 57 sites of the National Air Sampling Network (NASN). Weight losses for one and two years of exposure at each site were determined. Available climatic data were collected and average relative humidities and average temperatures were calculated. Average levels of pollutants were determined from collected NASN data. The pollutants of interest were gaseous sulfur dioxide, total suspended particulate, sulfate in suspended particulate, and nitrate in suspended particulate.
Multiple linear regression and nonlinear curve fitting techniques were used to analyze the relationship between corrosion behavior of this steel and the collected atmospheric data. The resulting best empirical function has the form: cor=a0te[a1sula2/RH]where cor = depth of corrosion, μm t = time, years sul = average level of sulfate in suspended particulate (μg/m3) or average level of sulfur dioxide (μg/m3) RH = average relative humidity According to statistical analysis, differences in average temperature, average total suspended particulate, and average nitrate in suspended particulate caused insignificant changes in this steel's corrosion behavior. Sulfur dioxide was a significant variable only when sulfate in suspended particulate was not included in the regression analysis. The levels of these two pollutants generally change together from site to site (exhibit a high degree of covariance). Therefore, sulfate in suspended particulate may be a substitute variable for sulfur dioxide.
Seven-Year Exposure at Point Reyes, California
Authors: Ailor WH 
Published: March 2009

This report is concerned with the data obtained from the seven-year Point Reyes, California removals (second exposure). These exposed panels included 39 alloys of eight basis metals of the 1957 program.
Previous reports concerning this program may be found in the Committee B-3 reports in the ASTM Proceedings for 1959, 1961, and 1962 and in the Committee G-l report (1966 Proceedings).
A number of test panels were lost due to the work of vandals at the Point Reyes test site during the fall of 1962. A fence subsequently erected should protect panels still exposed for future years. Replacements for seven- and twenty-year panels for most alloys were exposed on 12 June 1964. The seven-year panels were removed by task group member T. J. Summerson on 6 June 1971 after a total of 2550 exposure days. The twenty-year test panels remain on the racks for subsequent removal.
Prediction of Environmental Pitting and Corrosion Rates
Authors: Shuler RN , Ailor WH 
Published: March 2009

For nearly 15 years the environmental test results from long-term exposures have been handled by a computer program. Over 1 14-million bits of information representing data from more than 250 metals and alloys on test at fifteen atmospheric and two seawater locations are included in the program. Calculations are made reflecting aging changes, and changes due to the cleaning procedure and to corrosion. A printout then gives corrosion rates and mechanical property changes for each time period. Data points include 1,2,7, and 20 years for atmospheric specimens and 1, 2, 5, 10, and 20 years for seawater tests. Exposures of new alloys are made each year as phases of the continuing program along with appropriate removals of exposures from earlier series.
Since at least three data points are now on hand from some test metals, it is feasible to predict both corrosion rates and extreme pitting values for future removals. The corrosion rates and pitting data are subjected to curve fitting techniques through a computer operation. Several models were considered. However, based on earlier published studies on aluminum, we decided to begin with a least-squares fit of the cube-root pitting equation, d = kt1/3. Future work with other models may indicate improved reliability.
It is now possible to predict the 20-year corrosion rate for a marine environment and to estimate the time to perforation for a given alloy system. Actual 20-year data, when available, will be compared with these predicted values. Also included in the program is the capability to predict 10-year results when shorter-term data (1,2, and 5 years) are on hand.
Influence of Laboratory Test Method on Fatigue Test Results for Asphaltic Concrete
Authors: Irwin LH , Gallaway BM 
Published: March 2009

Fatigue characterizations obtained using three laboratory repeated-load, flexure test methods were compared. The test methods included uniaxial stress fields (beam specimens), biaxial stress fields (plate specimens), full stress reversal, and no stress reversal. In addition, specimens were sawn from field-compacted asphaltic concrete, and test results were compared with those from laboratory prepared specimens.
The degree of stress reversal and possibly the type of stress field to which the specimens were subjected were found to influence the resultant slope and intercept of the fatigue curve. The results of a comparison of fatigue characterizations obtained with laboratory and field-compacted specimens were not clear due to differences in the air void contents of the two mixtures.
An analysis to determine the minimum number of specimens required for fatigue characteristics using the beam test method suggested (but did not prove) that approximately ten specimens having 3 in. (76 mm) widths and depths should be used.
Dynamic Testing of Bituminous Mixtures for Permanent Deformation Response
Authors: Morris J , Haas RCG 
Published: March 2009

Permanent deformation, fatigue, and shrinkage fracture are the three major distress mechanisms found in flexible pavements. To date, however, little quantitative information is available on the fundamental material characteristics related to load-associated permanent deformation. The response and characterization of paving materials have proven to be complex problems. This situation has retarded the development of a reliable deformation predictive technique and, consequently, a systematic pavement design process.
This paper briefly discusses available permanent deformation predictive approaches. It is indicated that current techniques are inadequate in their present form. A new approach based upon laboratory tests under simulated field conditions is advanced, and the essential operating characteristics of associated materials characterization test equipment are outlined. The apparatus, which includes a temperature-controlled triaxial test chamber, electrohydraulic systems for independent control of axial and lateral dynamic stresses, and ancilliary measuring instruments is described.
The equipment can be used to evaluate a wide variety of conditions and paving materials. The test results have been used as input data to the development of statistically based models for predicting the permanent deformation of full-depth sections at the Brampton Test Road, Ontario. Excellent agreement between measured and predicted values have been obtained.
Impact Properties of Shock-Strengthened Type 316 Stainless Steel
Authors: Sheckherd JW , Kangilaski M , Bauer AA 
Published: March 2009

The effect of shock strengthening on impact properties of Type 316 stainless steel at temperatures ranging from room temperature to 650°C (1202°F) was established by utilizing the instrumented Charpy impact test. It was found that the total impact energy absorbed progressively decreases with increasing shocking pressure.
The dynamic yield strength (σdy) was increased by increasing the shocking pressures for all testing temperatures. This trend is expected because the static yield strength (σsy) was also found to increase with increasing shocking pressure. However, the ratio of dynamic-yield to static-yield strengths (measure of strain-rate sensitivity) was found to decrease with increasing shocking pressure.
Erosion-Corrosion of Finned Heat Exchanger Tubes
Authors: Van der Horst JMA , Sloan CR 
Published: March 2009

Converted reformer gas on the shell side of a heat exchanger was cooled by water on the tube side. In addition to hydrogen and nitrogen, the gas contained substantial quantities of CO2 and water vapor. The tubes were integral finned of C-steel. Condensate from the gas stream filled the space between fins, while CO2 from the stream dissolved into the water. Maximum gas velocity was of the order of 150 ft/s.
In the areas of highest gas velocity the fins had disappeared completely. In more or less stagnant gas areas the fins were corroded but still present, attack in intermediate areas ranging between the two extremes. The difference in corrosive attack between various areas clearly demonstrates the relatively modest effect of pure corrosion under these circumstances. On the other hand, the maximum velocity is about half the threshold velocity cited in the literature for steel. The synergistic effect of corrosion and erosion is therefore unmistakable. It may be assumed that impact of water droplets continuously removes the corrosion layer and thus accelerates the process.
The corrosive effect of CO2 at ambient temperatures is often belittled, but should not be, especially when assisted by high-velocity gas.
Incidentally, the use of finned tubing in an environment producing condensate is absurd since condensation removes any heat-transfer advantage of the fins. Recalculation in fact showed that the fins were unnecessary.
Erosion of Fused Silica by Glass Beads
Authors: Adler WF 
Published: March 2009

An analytical approach to particle erosion of brittle material surfaces is being developed based on a statistical model of erosion pit nucleation and growth[1,2]. For solid-particle erosion the Hertzian theory of impact is being considered in order to introduce the kinematic and material parameters into the general statistical formulation of the erosion process. In order to minimize the number of unknown factors in the initial development of a predictive erosion theory, the particular case of spherical glass beads impacting directly on the plane surface of relatively flaw-free fused silica (Corning 7940) has been investigated.
The erosion mechanisms in fused silica have been identified for both 70- and 290-μm glass beads impacting at 61 and 91.5 m/s. The experimentally observed erosion mechanisms could be correlated with the measured erosion rates, and it was substantiated that the solid-particle erosion of fused silica could be modeled in terms of preferential pit nucleation and growth. The controlled erosion tests provided evidence for the applicability of the Hertzian relations to the impact conditions associated with solid-particle erosion.