bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long-Term In-Reactor Corrosion and Hydriding of Zircaloy-2 Tubing
Authors: Hillner E 
Published: March 2009

Three original Zircaloy-2 clad blanket fuel bundles from the pressurized-water reactor (PWR) at the Shippingport Atomic Power Station were discharged after continuous exposure during Cores 1 and 2. Detailed visual examination of these components after ∼6300 calendar days of operation (51 140 effective full power hours) revealed only the anticipated uniform light gray (posttransition) corrosion products with no evidence of unexpected corrosion deterioration, fuel rod warpage, or other damage. All corrosion films were found to be tightly adherent to the underlying cladding.
An extensive destructive examination of a selected fuel rod from each of three fuel bundles produced, as expected, significantly greater end-of-life rod average oxide film thicknesses when compared with corresponding values calculated from the time-temperature history of each component, employing a set of empirical equations generated from the out-of-pile (autoclave) testing of Zircaloy coupons. It is shown that the pretransition region and the time to transition are in adequate agreement with the empirical equations generated from the ex-reactor data but that there is a significant acceleration of the posttransition corrosion rate due to the irradiation exposure. Post-transition corrosion rate data were used to develop an empirical expression of the form R′=A(φ)n·R where R′ is the in-reactor posttransition corrosion rate for Zircaloy-2 tubing, A and n are experimentally determined constants, φ is the posttransition fast flux exposure, and R is the posttransition temperature-dependent corrosion rate generated from exreactor (autoclave) testing. The Multipurpose Extended Life Blanket Assembly cladding in the mid-sections of the rods (α microstructure) was found to have corroded at a rate that is approximately 25 percent greater than the corresponding welded end cap regions (β-quenched struture).
It has been observed that the total hydrogen content of the cladding was less than that calculated from the ex-reactor expressions, using the measured oxide film thickness. It has also been found that the hydrogen pickup per unit weight gain is two to three times greater in the late posttransition period than that observed in the early posttransition region, possibly casting doubt on the validity of the application of the ex-reactor hydrogen pickup expression (that is, a constant ΔH/Δ0 ratio for the entire posttransition region) to in-reactor exposures.
Stress Relaxation of Steel Tendons Used in Prestressed Concrete Under Conditions of Changing Applied Stress
Authors: Glodowski RJ , Hoff GE 
Published: March 2009

Several methods have been proposed for predicting the total prestress loss in prestressed concrete structures. Inherent in all of these methods is the concept that the applied elastic strain on the steel tendons changes with time due to creep and shrinkage of concrete. A procedure most often used to determine the steel tendon's stress relaxation contribution to total prestress loss is a time iteration technique. The stress relaxation that occurs in each time interval is predicted from an equation describing stress relaxation as a function of time and initial stress level. This equation is normally derived from data obtained from constant-strain tests as per ASTM E328. During the time iteration program, however, the initial stress level is different for each time interval because of changing elastic strains in the steel tendons due to concrete creep and shrinkage. In some procedures under consideration by the prestressed concrete industry, the actual stress on the tendon at the start of each time interval is assumed to be the correct value for initial stress. Total relaxation is then determined by a summation of the relaxation during each time interval.
The object of the present research is to investigate the effects of variable applied elastic strain on stress relaxation results during a continuous test and to evaluate procedures for assessing these effects. To accomplish this, stress relaxation tests were carried out on 6.35-mm (0.250-in.) diameter prestressing wire. Results of variable elastic strain application during the test were compared with constant-strain stress relaxation data. Based on these results, a new procedure is proposed for predicting the effects of variable elastic strain on the stress relaxation-time relationship. This new procedure incorporates the effect of stress relaxation in prior time intervals on predicted stress relaxation in a given interval. This is accomplished analytically by defining an “effective initial stress” and an “effective time” to be used in the mathematical expression for stress relaxation during each time interval. This new procedure is shown to be more accurate in predicting actual stress relaxation results under conditions of changing applied elastic strain.
Slow Strain-Rate Stress Corrosion Testing for Liquid Metal Fast Breeder Reactor Steam Generator Applications
Authors: Indig ME 
Published: March 2009

A high-temperature slow strain-rate facility was developed to evaluate the stress corrosion resistance of alloys considered for the construction of liquid metal fast breeder reactor (LMFBR) steam generators. The primary concern was stress corrosion that might occur on the water side during steam generator operation in locally faulted caustic environments. Most of the studies were performed at 316°C in 5 or 10 percent sodium hydroxide (NaOH) solutions with 2¼Cr-1Mo steel and Incoloy-800.
With minor modification, the slow strain-rate test was converted to a straining electrode test. Experiments conducted by the straining electrode test permitted the study of stress corrosion behavior in the high temperature caustic solutions over a range of oxidizing potentials.
It was found that 2¼Cr-1Mo steel was extremely resistant to caustic cracking at 316°C in all metallurgical conditions tested by the slow strain-rate test and the straining electrode test. A few slow strain-rate tests performed at 232 °C in 5 to 10 percent NaOH resulted in intergranular and transgranular stress corrosion failures of 2¼Cr-1Mo steel.
Unlike 2¼Cr-1Mo, Incoloy-800 was susceptible to caustic cracking at 316°C. The susceptibility depended on the metallurgical condition and to some extent, the oxidizing potential. The cold-worked and Grade 1 conditions exhibited excellent resistance to caustic cracking in the slow strain-rate test. However, limited studies in the straining electrode test showed the Grade 1 condition could be readily cracked at anodic oxidizing potentials.
Validity of the Slow Straining Test Method in the Stress Corrosion Cracking Research Compared with Conventional Testing Techniques
Authors: Buhl H 
Published: March 2009

The appearance of a minimum in the susceptibility to stress corrosion cracking (SCC)/strain-rate curves obtained by slow strain-rate experiments has been examined carefully and a relationship between the repassivation rate of the material under investigation and the position of this minimum has been established.
For aluminum alloys, the results of the slow strain-rate experiments are not in complete agreement with the results of the conventional testing techniques. To explain this behavior, further experiments have to be carried out. At this moment, it seems to be doubtful whether the slow strain-rate testing technique is applicable to aluminum alloys.
The results with titanium alloys and high alloyed chromium- and chromium-nickel stainless steels obtained with different testing techniques (slow strain rate and constant load) are in very good agreement with each other.
Some Comparisons of the Slow Strain-Rate Method with the Constant Strain and the Constant Load Methods of Stress Corrosion Testing
Authors: Andrew JF , Heron JT , Stringer J 
Published: March 2009

Two practical stress corrosion investigations are outlined in which the results of slow strain-rate tests are compared with the results of other test methods.
The possibility of formulating a specification to cover the slow strain-rate stress corrosion test method is considered.
Portable Slow Strain-Rate Stress Corrosion Test Device
Authors: Hauser F , Abbott SR , Cornet I , Treseder RS 
Published: March 2009

A portable test device has been constructed for determining the stress corrosion cracking (SCC) characteristics of process environments. The device may be inserted and retrieved from laboratory, plant, and field equipment operating at pressures up to 13.8 MPa (2000 psi) and temperatures not exceeding 204°C (400°F) without shutting down the system. Specimens are loaded by the slow strain-rate method which has the advantage of producing SCC in a short period of time. The device is small enough to be inserted through a 2.54 cm (1 in.) diameter valve. A hydraulic cylinder, which requires a compressed gas supply as a power source, loads the specimens.
Initial testing was performed using low carbon steel specimens in air at room temperature. The hydraulic method of specimen loading performed smoothly and allowed constant strain rates as low as 4 × 10-7s-1-1 to be maintained ± 5 percent at a hydraulic system pressure of 2.76 MPa (400 psi).
Tests with AISI Type 304 stainless steel specimens in boiling (45 weight percent) magnesium chloride at 155°C (311°F) confirmed the applicability of the device for SCC studies. Indicators used include time to fracture, ultimate tensile strength, percent elongation, and visual observations for secondary cracks.
Estimation of Microbial Activities in Lake Sediments by Measurement of Sediment Gas Evolution
Authors: Ward TE , Frea JI 
Published: March 2009

The employment of an inverted sheet-metal cone permitted measurement of in situ evolution of methane and carbon dioxide from various Lake Erie sediments. The methane evolution rates varied from 0 to 71.5 mg/m2/h, while the carbon dioxide evolution rate reached a maximum of 6.1 mg/m2/h. The corresponding in vitro methane evolution or production rates demonstrated similar trends in some cases, but in other cases, obvious variations were observed. The in vitro variations in methanogenesis were attributed to the physical disruption of the sediment, which may have resulted in oxidation of the sample. The corresponding dissolved methane concentrations in the water column correlated well with the in situ methane evolution rates. In sediment regions where distinct lateral gradients of methanogenesis were observed, a corresponding gradient was observed in the overlying water column. Sediment regions consisting of clay, sand, or clay-sand mixtures showed no gaseous evolution. Minimal methane concentrations were observed in the water column above these sediments. The more active gaseous evolution occurred at near-shore regions, where external loadings contributed to the organic loading of the sediments.
The use of this inverted cone proved to be critical in assaying in situ methanogenesis. The in vitro methanogenic rates were susceptible to oxidation and resulted in variable estimations of net sediment methanogenesis. The association of this sediment methane and carbon dioxide evolution with sediment denitrification rates (nitrogen evolution) could provide valuable data for carbon and nitrogen budgets in freshwater systems.
Influence of Interstitial and Some Substitutional Alloying Elements
Authors: Plumtree A , Gullberg R 
Published: March 2009

The toughness of several vacuum-melted Fe-25Cr and Fe-18Cr-2Mo ferritic stainless steels containing between 40 and 1000 ppm combined carbon and nitrogen has been investigated in the water-quenched condition. The toughness of these alloys has been assessed using notched-bar impact tests. For a given interstitial content, the ductile-to-brittle transition temperature and the impact shelf energy were not influenced by the presence of 2 percent molybdenum or the change in chromium content from 18 to 25 percent. In order to achieve a low transition temperature and high shelf energy, the combined carbon and nitrogen (C + N) content should be maintained below 150 ppm, in which case the interstitial amount has no effect. Exceeding this threshold level results in a marked increase in transition temperature and decrease in shelf energy. At higher interstitial levels [∼600 ppm (C + N)] further increases are not as significant. Addition of nickel resulted in a decrease in transition temperature, but this was accompanied by a decrease in shelf energy when compared with plain chromium steels with the same interstitial content. The addition of titanium, however, caused an improvement in both transition temperature and impact shelf energy.
It is shown that increasing the interstitial content of these ferritic stainless steels is associated with an increase in the amount of second phase present, particularly at the grain boundaries. Such particles enhance cleavage fracture by reducing the surface energy. The tendency toward a more brittle condition with increased interstitial content and larger grain size is explained in terms of the Cottrell theory for brittle fracture.
Application of High-Purity Ferritic Stainless Steel Plates to Welded Structures
Authors: Nakazawa T , Suzuki S , Sunami T , Sogō Y 
Published: March 2009

This investigation deals with the practical application of high-purity 18Cr-2Mo-Nb ferritic stainless steel plates 6, 12, and 25 mm thick to welded structures.
In the V-notch Charpy test, the ductile-to-brittle transition temperature is about -30°C. The fracture toughness, Kc, determined by the deep-notch test is 350 kgf/mm2 · √mm for 12-mm-thick plate at -100°C. In the ESSO test, which has a temperature gradient, the Kc -value obtained is more than 400 kgf/mm2 · √mm at 0°C.
The toughness of the gas tungsten-arc welded joints using 316 L (C &lt; 0.02 percent) wire deteriorated to some extent, compared with that of the base metal. In the deepnotch test (notch position: fusion boundary, heat-affected zone), however, the Kc-value is more than 200 kgy/mm2 · √mm at 0°C.
It is generally recognized that the safety of a weldable structural steel can be secured if its weld zone has resistance to brittle fracture initiation and the base metal has brittle fracture arresting properties. It can be concluded, therefore, that in thicknesses up to 12 mm this material can be used for welded structures at service temperature above 0°C because of its excellent fracture toughness.
Since the toughness of 18Cr-2Mo-Nb deteriorates with aging above 300°C or in cold-working in excess of 10 percent, and even further deteriorates in strain-aging, these effects must be taken into account in its fabrication.
Weld Heat-Affected Zone Properties in AISI 409 Ferritic Stainless Steel
Authors: Thomas CR , Apps RL 
Published: March 2009

Although welding of thin-gage ferritic stainless steels is well documented, little information is available on the response of thicker (4.5 to 12.0 mm) sections to welding. With increasing interest in the use of heavier gages, it has become necessary to rectify this gap in knowledge. The work reported herein was undertaken to examine the metallurgical response of titanium-stabilized 11.5Cr steels to welding in terms of heat-affected zone (HAZ) structure, mechanical properties, and corrosion behavior.
Welds were made in four heats of steel to determine the thermal cycles occuring in the weld HAZ and to examine structures and give a general indication of joint properties. In order to examine the characteristics of different regions in the HAZ, a thermal simulation technique was used to produce specimens for examination and testing which had undergone a thermal cycle appropriate to a specific part of the HAZ. Parent steel, weldments, and simulated specimens were examined by optical microscopy, hardness testing, notch impact testing, and corrosion testing.
Four distinct regions of the HAZ were distinguished, as the HAZ was traversed from the unaffected parent steel to the fusion boundary. The amount of martensite formed reached a maximum where the HAZ peak temperature was in the duplex α + γ range. Impact transition temperature increased as the grain size increased, and martensite appeared to have little effect. In direct HAZ tests the transition temperature increased by 30 to 70 deg C irrespective of arc energy. Corrosion resistance deteriorated as the martensite content increased. Variations in nickel, manganese, and titanium within the steels used gave only minor variations in HAZ structure and properties, and it is concluded that compositional variations within the AISI 409 specification are unlikely to give significant improvements in the weldability of these steels.
Weldability of the New Generation of Ferritic Stainless Steels—Update
Authors: Krysiak KF 
Published: March 2009

The 26Cr-1Mo alloys stabilized with titanium and the 29Cr-4Mo alloys have many potential applications in the chemical process industries. There is particular concern about the effect of interstitial content and the titanium addition on weldability, weld fracture toughness, and ductility.
This paper discusses the weldability of the new titanium-stabilized 26Cr-1Mo and 29Cr-4Mo (26-1 and 29-4) alloys in various commercially available thicknesses [3.276 to 3.81 mm] (0.129 to 0.150 in.), using matching and dissimilar filler metals, and compares the ductility and impact toughness of these materials with those of E-BRITE 26-1 (a high-purity ferritic stainless steel). Both the gas tungsten-arc and shielded metal-arc welding processes were used.
Welds were evaluated on the basis of tensile, bend, Charpy V-notch impact properties, and weld metal interstitial content (carbon, nitrogen, and oxygen).
Sound welds were made in titanium-stabilized 26Cr-1Mo and 29Cr-4Mo alloys. It was concluded that welding procedures that optimize gas shielding must be used. Routine gas tungsten-arc welding procedures are not adequate. Because of the high ductile-to-brittle transition temperature and low notch toughness observed in the gas tungsten-arc welds, this procedure is not recommended for fabrication of chemical process equipment from the stabilized ferritic stainless steels in the thicknesses studied. It was found that the welds made with high-purity filler metal were superior to those made with the titanium-stabilized filler metal.
The fracture behavior and notch toughness of the shielded metal-arc welds made with Hastelloy C-276, Hastelloy G, and Haynes 25 were satisfactory, and these procedures can be used for fabrication of chemical process equipment.
Influence of Small Amounts of Niobium on Mechanical and Corrosion Properties of Type 304 Stainless Steel
Authors: Sikka VK , Moorhead AJ , Brinkman CR 
Published: March 2009

Creep and creep-rupture properties of several experimental heats of Type 304 stainless steel containing 20, 50, 100, 200, 500, 700, and 1000 ppm (by weight) of niobium were investigated in the temperature range of 482 to 649°C. Resistance to intergranular corrosion of these heats was also studied. Results of tests on the experimental heats were compared with the creep properties of 20 commercial heats of Type 304 stainless steel and data from the literature on several heats of Type 347 (4000 to 3000 ppm niobium) stainless steel.
Results on experimental heats were used to check that heat-to-heat variations in creep properties of 20 commercial heats of Type 304 stainless steel are caused by variations in carbon, nitrogen, grain size, and for the most part by residual niobium (10 to 200 ppm). The time to rupture increased and minimum creep rate decreased with increasing niobium content until a saturation level was attained at about 500 to 1000 ppm.
Type 304 stainless steel containing 500-ppm niobium offers superior creep and creep-rupture properties with improved creep ductility and a factor of approximately 5 better intergranular corrosion resistance [in boiling copper sulfate (CuSO4) solution] than Type 304 stainless steel (20-ppm niobium). In their welding work on the same heats, Moorhead et al have observed that Type 304 containing 500 to 1000 ppm niobium exhibits a weldability similar to that of Type 304 stainless steel.
Foamix Asphalt Advances
Authors: Ruckel PJ , Kole LL , Abel F , Zator RE , Button JW , Epps JA 
Published: March 2009

Research studies and road applications utilizing the Foamix process during the past four years were reviewed by a five-member panel. During that period, usage of foamed asphalt has expanded from two to 16 countries worldwide. A small stream of water injected into hot asphalt cement results in a large-volume stream of foamed asphalt for easy mixing with cold wet aggregates. Conventional equipment is used for mixing and laydown. A wide range of aggregates, including, in particular, local marginal-quality materials, can be used.
Outside Australia and New Zealand, trial sections were constructed during 1977 in South Africa and Colorado, later in Botswana, France, and Germany, and most recently in Michigan. A full-depth, 9-km (5.6 mile) road was completed in North Dakota during the fall of 1979. Most use is for base sections ultimately given surface protection. One trial was an in situ application to recycled material. Foamixes have performed as unsealed liners for sewage lagoons and as stockpiled patch material.
Reviews of research studies in Colorado, California, and Texas provide a broad range of data from a variety of aggregates and test procedures. A counteragent has been developed to negate the effect of antifoam additives present in some asphalts.
Carbon Black Reinforcement of Asphalts in Paving Mixtures
Authors: Vallerga BA , Gridley PF 
Published: March 2009

Dispersion of submicrometre-size carbon black particles in asphalt at dosages of 11 to 16 percent by weight of asphalt has been found to improve the asphalt properties of durability, wear resistance, and temperature-viscosity susceptibility. This concept of reinforcing asphalts with a carbon black filler has been made practical by pelletizing the carbon black with a high-durability maltenes binder compatible with asphalts. The pellets are packaged in 11.34-kg (25 lb) polyethylene bags which are introduced, bag and all, into hot-mix cycle of asphalt concrete batch-type plants. In continuous-type plants, the pellets are added either through the asphalt feedline in correct proportion to the hot asphalt or through the hot aggregate feed in correct proportion to the hot aggregate.
Since the carbon black becomes part of and bulks the asphalt, adjustments are made in batch weights to keep the volume relationship of binder to rock constant. Other design considerations are discussed.
Effects of the carbon black addition on the properties of asphalts and asphalt concrete, as measured in both laboratory and field experiments, are shown. The present status of a continuing program of field testing and evaluation is described.