bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production and Properties of Valve Bodies Made of Stabilized Chromium-Nickel Steel Castings for the Charge in Nuclear Power Stations
Authors: Achtelik K 
Published: March 2009

Castings used in nuclear power stations are subject to extremely high quality specifications. The example of cast steel housings with a unit weight of 1.7 metric tonnes made of a steel similar to ASTM A296, Grade CF-8C, is used to show that by consistent application of foundry practice castings can be produced that meet the highest requirements.
In castings a basic distinction is made between systematic and statistical flaws: Systematic flaws are defined as those occurring at one and the same point in all castings made from one and the same pattern, such as shrinkage and cracks. These flaws are predictable and, therefore, avoidable through proper preparation of casting technique and exact application of good foundry practice. Statistical flaws are defined as flaws distributed at random over the casting, such as gas holes and nonmetallic inclusions. While it is true that these flaws are not predictable, they can be influenced to a considerable degree through well-directed measures in designing the gating technique. Such measures are described.
The effectiveness of the preceding measures is shown on the basis of the extent of repair to the trial castings and the influence of corrective actions on the extent of repair.
German rules prescribe a notch impact strength of not less than 80 J as an average of three specimens of austenitic steel grades, where the notch impact strength of the individual specimen should not fall below 67 J. It is shown that the carbon content must be kept as low as possible and a niobium/carbon ratio of approximately 8:10 must be attempted. These aspects were taken into consideration when establishing the melting analysis. The tensile properties and the notch impact strength are given for wall thicknesses of 60, 100, and 300 mm. Investigations on construction welds confirm the influence of the niobium/carbon ratio on the notch impact strength values of weld deposits.
Castings meet high safety requirements equally as well as components made by other production processes, with advantages such as freedom of design, optimum flow design, and direction-independent material properties.
Predicting and Evaluating Ferrite Content in Austenitic Stainless Steel Castings
Authors: Leger MT 
Published: March 2009

The amount of ferrite in a stainless steel casting depends not only on the average chemical composition but also to a great extent on the segregation of γ-formers and α-formers, which is controlled by the solidification and cooling rates in the mold, and hence on the thickness of the casting.
The study first demonstrates the combined influence of chemical composition and thickness on the ferrite content measured in stepped bars of 5- to 60-mm thickness made of steels with compositions similar to that of the French Z6 CND 18 12-M (or American CF8M) grade, leading to an improved empirical prediction formula taking thickness into account.
The second part of the study proposes a dilatometric method for ferrite measurement that offers the advantages of performing the measurement on a volume and of not being affected by phase morphology. The ferrite content is calculated from the measurement of the linear expansion coefficient of the specimen and prior knowledge of the respective expansion coefficients of the phases present (austenite and ferrite) which are related to the composition of each of these phases. On the basis of microprobe analyses and measurements of the expansion coefficients of single-phase specimens, we have prepared nomographs making it possible to predict these coefficients on the basis of the average composition.
Influence of Long-Time Aging of CF8 and CF8M Cast Steel at Temperatures Between 300 and 500°C on Impact Toughness and Structural Properties
Authors: Trautwein A , Gysel W 
Published: March 2009

The object of this work was to investigate the influence of long-time aging at elevated temperatures between 300 and 500°C and aging times up to 65 000 h on the impact toughness and the structural properties of CF8 and CF8M cast steels. The results are derived from 18 production heats with varying chemical analysis and varying contents of ferrite.
The observed aging effect is based on the 475°C embrittlement of the ferritic phase of these steels. In the range between 300 and 400°C the embrittlement is very uniform and can be described by a thermal activated process with the low activation energy of about 24 000 cal/mol. The activation energy permits a physically accurate description of the time-temperature relation of the aging process and a precise interpretation of the results. For the actual material performance the content of ferrite is of great importance.
Additional investigations studied the influence of aging on the ductile-to-brittle transition of impact toughness. It shows that with increasing aging not only the transition shifts to higher temperatures, but also a lowering of the upper shelf occurs. This effect can be mathematically described by means of three parameters which are aging-dependent. Basically, it allows prediction of the influence of aging on the ductile-to-brittle transition for arbitrary aging conditions.
Comparison of the Properties of the HK-40 and HP-45 Cast Heat-Resistant Alloys
Authors: Roach DB , VanEcho JA 
Published: March 2009

During the past ten years, considerable interest has developed in the use of the HP-45 alloy for high-temperature furnace components, and this alloy has replaced the conventionally used HK-40 alloy in some critical applications. The wide use of the HP-45 alloy, however, has been retarded by the scarcity of long-time creep-rupture data.
This paper presents the results of different research programs conducted at Battelle over the past several years and compares the properties of the HP-45 and HK-40 alloys. Included are comparisons of the short-time tensile and long-time creep-rupture properties, the effects of long-time exposure on the tensile and impact properties, the elastic properties, and the surface and microstructural stability of the two alloys. Creep-rupture comparisons are based upon the results of tests of up to 10 000-h duration at 871, 982, and 1093°C (1600, 1800, and 2000°F) on three commercially produced heats of each alloy.
Weld Procedure, Filler Metal, and Post-Weld Heat Treatment—Their Effect on the Hardness and Quality of Welds in CA6NM Alloy
Authors: Loveless RW , Smith WC , Templeton HC 
Published: March 2009

The hardness of repair welds in CA6NM alloy has consistently been higher than the hardness of the base metal, regardless of the post-weld heat treatment used. The purpose of this investigation was to establish the optimum post-weld heat treatment to use in order to obtain the lowest hardness and to establish expected hardness limits for repair welds.
Simulated repair welds 13 mm deep, 25 mm wide, and 51 mm long (½ by 1 by 2 in.) made in cast CA6NM plates 51 by 178 by 305 mm (2 by 7 by 12 in.) by the shielded metal arc weld (SMAW) and gas tungsten arc weld (GTAW) processes using 12Cr-4Ni filler metal were evaluated as to hardness in the as-welded condition and after various post-weld heat treatments. The plates were normalized at 1050°C (1925°F) and double tempered at 675 + 607°C (1250 + 1125°F) prior to welding and conformed to the tensile requirements of ASTM A487, Grade CA6NM. Plate hardness was 255 to 269HB.
As-welded SMAW welds were 387HB to 418HB; the heat-affected zone (HAZ) hardness was 340HB. Single-tempered SMAW welds [temper 607°C (1125°F)] were 302HB. Double-tempered SMAW welds [temper 675 + 607°C (1250 + 1125°F)] were 293HB.
SMAW welds which were normalized at 1050°C (1925°F) followed by tempering were harder than welds tempered only. Single tempering at 607°C (1125°F) resulted in weld hardness of 321HB; double tempering at 675 + 607°C (1250 + 1125°F) produced a weld hardness of 302HB.
GTAW welds (no molybdenum in filler metal) resulted in lower hardness of welds, 241HB to 286HB after double tempering at 675 + 607°C (1250 + 1125°F). Normalizing of GTAW welds followed by the double-tempering treatment produced a weld hardness of 235HB.
A smaller simulated repair 6 mm deep, 13 mm wide, 25 mm long (¼ by ½ by 1 in.) was made in one plate by the SMAW process using nickel-chromium-iron filler metal (Inconel 600). Hardness was determined in the as-welded condition only—weld hardness 170HB to 187HB, HAZ hardness 302 HB.
All plates and welds were nondestructively examined by radiographic, ultrasonic, and penetrant techniques, and met the requirement of Section III of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, as per Table 1.
All welding was done in the flat position without preheat, using procedures qualified in conformance with Section IX of the ASME Code. Root passes of SMAW welds were made with 3.175-mm (⅛ in.) electrodes; 3.968-mm (5/32 in.) electrodes were used for final passes. GTAW welds were made with 3.175-mm (⅛ in.) filler wire throughout.
The lowest hardness of welds made with filler metal of the same composition as the base metal is obtained by a double-temper post-weld heat treatment of 675 + 607°C (1250 + 1125°F). Expected weld hardness will be about 293HB. Minor repair welds can be made with nickel-chromium-iron filler metal with weld hardness and strength compatible with the cast alloy without post-weld heat treatment.
CA6NM: New Developments Based on 20 Years' Experience
Authors: Gysel W , Gerber E , Trautwein A 
Published: March 2009

Development of CA6NM cast steel is reported and the present state of the international standards is discussed.
The influence of the argon oxygen decarburization (AOD) process on CA6NM is shown by means of a statistical evaluation of preliminary quality-control test specimens from the four year period 1975–1979. The influences of reducing the carbon content to 0.030 percent and the sulfur content to 0.004 percent on the impact energy are given special attention. The impact energy values were improved by 18 to 73 percent, depending on test specimen shape and test temperature. This resulted in a high average value (Charpy V-notch, + 20°C: 152 ± 21 J) even on heavy-walled castings. A further statistical evaluation verifies that CA6NM cast steel with a strength level of 950 MPa also has excellent impact values (Charpy V-notch, +20°C: 67 ± 19 J).
The increase in steel quality due to the AOD refining process becomes evident especially for large cross sections. These have an improved primary structure. By using massive stepped test blocks with step thickness of up to 500 mm, it is shown that the drop in reduction-of-area and elongation values from surface-to-core location observed in earlier investigations on basic electric-arc furnace products disappears completely. In addition, the corrosion fatigue limit values in the core of 500-mm sections are up to 30 percent higher than for good arc furnace steel. Since the phosphorus level in the AOD test block was purposely aimed at a relatively high level of 0.021 percent, this effect must be attributed to the very low nitrogen, hydrogen, oxygen, and sulfur contents in the AOD steel. As a result of the higher degree of cleanliness, the Charpy V-notch upper-shelf energy level as well as the transition temperature show marked improvement even in the core location.
The optimum welding conditions are described. The importance of welding electrode quality control and the question of post-weld heat treatment are discussed.
To supplement the documentation of the material's potential for low-temperature applications, technical base material data are presented. The conditions for obtaining satisfactory weld properties at temperatures of −110°C, using electrodes of composition similar to the base material, are described. The procedures are applicable for fabrication and repair welding.
In light of a possible replacement of austenitic-ferritic castings by CA6NM for parts used in primary cooling loops of nuclear reactors, it is shown that heats with a high initial impact energy undergo in principle the same long-term aging process which occurs for predominately austenitic cast steel.
Through-the-Thickness Tensile Strength of Fiber-Reinforced Plastics
Authors: Mao TH , Owen MJ 
Published: March 2009

The through-the-thickness tensile strength of fiber-reinforced plastics is difficult to measure, but for some purposes it is a significant design property. This property appears to be critically dependent on the test method and specimen preparation. The authors have examined the possibility of producing tensile failures in a disk subjected to diametral compression, a method well known in the field of testing of brittle isotropic materials.
In the isotropic case there is a uniform tensile stress distribution perpendicular to the diameter which is the axis of compression. Slices of round pultruded rod are transversely isotropic, and the method of test gives convenient and consistent results.
Results are also presented for the through-the-thickness strength of laminated materials. The disks were prepared by turning a cylindrical bar from a piece of thick laminate. Stress distributions have been analyzed by finite element analysis and compared with published theory. Both methods have been compared with strain gage results obtained from orthotropic disks. The finite element results agree quite well with published theory, but there is considerable scatter in the strain gage results. Experimental results for the strength of disk samples are consistent and compare well with other methods. The disk method also appears to be economical.
Strength and Fracture Characteristics of Graphite-Glass Intraply Hybrid Composites
Authors: Bhatia NM 
Published: March 2009

The strength, stiffness, fracture toughness, and crack propagation characteristics of graphite-glass intraply hybrid uniwoven and biwoven composite fabric materials are evaluated. The hybrid fabric plies were designed by modifying existing all-graphite fabrics in which were added single tows of S-glass spaced 6.35 mm (0.25 in.) apart, and 12.70-mm (0.5-in.)-wide strips of graphite were replaced with S-glass spaced 10.16 cm (4.0 in.) apart. The purpose of this hybrid design was to provide better damage tolerance and damage containment capabilities than the all-graphite system.
The test program involved unidirectional and laminated coupons for strength and fracture toughness evaluation and 30.5-cm (12.0-in.)-wide orthotropic panels for crack arrestment evaluation. The panels were designed with glass strips aligned in discrete and staggered configurations. All tests involved room temperature dry and 121°C (250°F) 1.2 percent moisture-content specimens. The test results showed that the strength and stiffness properties for the hybrid materials were within 10 percent of the comparable all-graphite materials. However, the fracture toughness was approximately 44 percent higher for the hybrid systems and was not degraded by the 121°C (250°F) wet environment. A distinct crack arrestment capability was achieved only with the discrete strip configuration, with ultimate failure strain after crack arrestment in the 0.64 to 0.76 percent strain range.
Indentation Law for Composite Laminates
Authors: Yang SH , Sun CT 
Published: March 2009

Static indentation tests have been conducted on glass/epoxy and graphite/epoxy composite laminates with steel balls as the indentor. Beam specimens clamped at various spans were used for the tests. Loading, unloading, and reloading data were obtained and fitted into power laws. It was found that the contact behavior is not appreciably affected by the span. Both loading and reloading curves seem to follow the 1.5 power law, and the unloading curves are described quite well by a 2.5 power law.
An interesting finding is a critical indentation (αcr) that can be used to predict permanent indentations in unloading. Since αcr only depends on composite material properties, only the loading and an unloading curve are needed to establish the complete loading/unloading behavior. According to the present model, no reloading tests are necessary for deriving the reloading law.
Residual Life Prediction of Jet Engine Rotor Disks
Authors: Zako M , Kawashima T , Aono H , Jimboh K , Ohnabe H , Miyoshi T 
Published: March 2009

For the application of this study, an aircraft jet engine rotor disk under constant temperature (room temperature) is selected. Assuming crack initiation to occur at the rim slot of an aircraft jet engine rotor disk under constant temperature (room temperature) for the application of this study, and converting the three-dimensional stress into a two-dimensional one, their life prediction is analyzed. The life prediction system was predicated on stress analysis, nondestructive testing, and material properties. The stress at the cracked part of the rim slot is calculated by the finite-element method, and the crack propagation is calculated by Paris's rule. Assuming KIc and the difference between KIc and calculated K—that is, (KIc − K)—to be a Gaussian distribution, safety is estimated by the relationship between fracture probability, Pf, and standard deviation.
In the numerical examples, assuming an elliptic surface crack at four different parts of the rim slot, the crack propagation after 2000 cycles is calculated. The safety factor of rotor disks is judged by the value of (KIc – K).
Cone Penetration and Laboratory Testing in Marine Calcareous Sediments
Authors: Beringen FL , Kolk HJ , Windle D 
Published: March 2009

The paper discusses in situ cone penetration and laboratory testing of calcareous soils at several offshore locations. These tests indicate a large range in degree of cementation.
The laboratory program includes special strength and deformation tests to further clarify and interpret the results of cone penetration tests. In addition, these tests are designed to provide a better understanding of the behavior of pile foundations.
Based on the preceding results a classification system is proposed for these types of soil with emphasis on in situ measurements. Furthermore, engineering design parameters are discussed and values suggested for skin friction and end bearing for pile foundations.
Strength Characteristics of Caliche Soils of the Tucson Area
Authors: Post JL 
Published: March 2009

The physical and chemical composition of caliche soils of the Tucson, Ariz. area were investigated to determine the compressive strength of indurated and crushed calcisols. The results of stabilization of crushed calcisols with portland cement additive were determined and the soil-cement reaction products were investigated.
Soil minerals were identified by X-ray diffraction analysis. The calcisols were found to consist mainly of feldspar and randomly oriented microcrystalline calcite with lesser amounts of quartz and clay minerals.
The strength of the calcisols was found to be inversely related to their clay content, with unconfined compressive strengths varying from less than 1.03 MPa (150 psi) to more than 20.67 MPa (3000 psi). When the indurated caliche was crushed it behaved as an inert granular material with no immediate recementation when compacted.
It was shown that a loss of compressive strength generally occurred in the remolded soil-cement mixtures after 28 days of curing, the maximum 28-day compressive strength, using 10 percent portland cement, varying from 2.51 to 7.80 MPa (364 to 1132 psi). The compressive strength was a function of the amount of portland cement added and of the combined feldspar-calcite content of the soil.
The feldspars of the Tucson basin were found to consist mainly of intermediate microcline with lesser amounts of orthoclase and oligoclase. The weak soil-cement bonding strengths appear to be due to the feldspars and the strength losses which occur are the result of the chemical interaction of the calcite and alkali feldspars with the portland cement in an aqueous environment. Portland cement is an unreliable additive for the effective stabilization of crushed calcisols.
Automotive Engine Coolants: A Review of Their Requirements and Methods of Evaluation
Authors: Rowe LC 
Published: March 2009

A brief review of early automobiles shows the development of the engine cooling system, and some of the associated problems with these early cars are discussed.
A liquid is commonly used to transfer heat from an operating automobile engine to a radiator where the heat can be dissipated to the air. In order that the liquid perform effectively, it must have the appropriate chemical and physical properties. Of foremost consideration is the capability of the fluid to transfer heat over a wide range of operating conditions. In addition, the fluid must be stable, must not freeze when not in use or boil during or after engine operation, and must not cause or allow excessive corrosion of the parts it contacts.
To determine how well the cooling system is capable of performing its function, it is necessary to perform a variety of tests to evaluate the operational characteristics of component parts, the properties of the coolant fluid and its long-range stability, and the capability of the fluid to minimize corrosion of all materials. Tests range from the shorttime laboratory test to the longer and more comprehensive field test. Operating conditions are often difficult to simulate in the laboratory, and the test tends to be restrictive. Field tests are usually more definitive but can be difficult to control. However, the end result of an effective development program over a number of years has been a cooling system that has provided good durable service.
Corrosion Testing of Furnace and Vacuum Brazed Aluminum Radiators
Authors: Naruki K , Hasegawa Y 
Published: March 2009

To investigate the internal corrosion behaviors of aluminum radiators processed by vacuum brazing and furnace brazing with flux, respectively, a glassware test was conducted on a specimen and a coolant circulation test on actual radiator units.
It was proved that the furnace-brazed radiator was superior to the vacuum-brazed radiator, as far as the corrosive resistance was concerned, since the former incorporated the zinc diffusion layer in its surface which afforded the sacrificial corrosion.
The Echelle Spectrograph as a Solution to Some Problems Commonly Encountered in Other Instrumental Analysis
Authors: Shope JR 
Published: March 2009

The echelle spectrograph, with a direct current plasma jet as the emission source, is used to solve some common analytical problems. The instrument replaces atomic absorption when burner blockage becomes a problem and also when methyl isobutyl ketone (MIBK) must be used with a nitrous oxide (N2O) flame. The system is also shown to be more applicable to analysis than the direct reading emission spectrograph when sample variations are considered.
To ensure a basic understanding of the instrument, its differences and similarities to both atomic absorption and emission spectroscopy are compared. These comparisons are intended for problem solving and are limited to the instrumentation available in this laboratory.