bluuebunny/crossref_metadata_2025 huggingface dataset:
Introduction
Authors: Wenk Sam
Published: August 2009

Committee E-7 on Nondestructive Testing has, since its inception, assumed responsibility for presenting advanced concepts of control and inspection testing to the membership of the Society, and through it to the general and specific industrial communities. In keeping with this responsibility, the present symposium was initiated for a two-fold purpose: (1) to establish a background of unclassified literature on a limited number of specific applications of nondestructive testing; (2) to stimulate thinking by outlining many of the present nondestructive testing problems in the missile industry. This new, but highly dynamic industry is beset with a multitude of problems involving the measurement of properties and evaluation of materials for extremely severe environmental conditions. Missile materials must withstand severe temperature, pressure, radiation corrosion, and stress levels to meet design performance. Consequently, nondestructive test methods must be able to furnish quantitative information to insure that the proper quality levels have been met.
Radiography of Large Solid Propellant Rocket Motors
Authors: Criscuolo E. L. , Holloway J. A. , Polansky D. , Dyer C. H.
Published: August 2009

This paper presents experimental data on the radiography of propellant and information on the inspection of the Polaris motor. The X-ray energy range investigated was from 2 to 26 Mev. The half value layer thicknesses for propellant were determined to be 2.85, 6.5, and 7.7 in. for X-ray energies of 2000 kvp, 10 Mev, and 22 Mev, respectively. Experimental data with a penetrameter sensitivity of 0.25 per cent were obtained through 40 in. of propellant, using a 22-Mev betatron. The radiographic techniques with a 22-Mev betatron have been applied to the inspection of the Polaris motor. The use of a linear accelerator in X-ray inspection of propellant is feasible. This machine with its characteristically high output should materially reduce inspection time and costs.
Ultrasonic Inspection of Adhesive-Bonded Aluminum Sandwich Structures
Authors: Kammerer Calvin C.
Published: August 2009

North American Aviation, Inc., has been in the adhesive bonding field for the past eight years. During this time, the company's Torrance California Facility has produced over 150,000 adhesive-bonded aluminum sandwich structures. The quality of these honeycomb assemblies has been controlled by conscientious application of rigid in-process control covering cleaning, etching, priming, and bonding. Nondestructive inspection of the end product has been limited to sonic methods, generally outgrowths of the original coin-tapping principle. By variations in audible response, this sonic inspection will detect gross voids but will not indicate substandard bonds. Unfortunately, this lack of effective nondestructive inspection of the end product has discouraged the full utilization of this valuable sandwich construction. Conventional structures are still being used despite the obvious weight penalty. One of the reasons for this is the difficulty of convincing designers that bond quality can be reliably checked and guaranteed by tapping the outside of a sandwich structure. With added confidence in the quality of bonds, the 150,000 or more parts produced by the company could have easily been 500,000 or even a million, considering the large number of F-86 and F-100 aircraft delivered. Being acutely aware of the need for an effective system of nondestructive inspection, the company's quality control laboratory has been evaluating all available nondestructive testing techniques for the past four or five years—the STUB meter, variations of the STUB meter (Coindoscope), thermally sensitive dye coatings, frost patterns, and vibrating sand patterns. The final decision was in favor of two dissimilar yet complementary ultrasonic techniques.
Ultrasonic Standards for the Evaluation of Missile Materials and Components
Authors: Adams C. T. , Morris J. W.
Published: August 2009

Ultrasonic standards for evaluating internal discontinuities in high-temperature forgings, weldments, and brazed joints are discussed. The relatively large differences in ultrasonic attenuation between different materials show that requirements for reference test blocks should be based on ultrasonic properties rather than chemical composition or other attributes of the material. Several applications of specialized ultrasonic inspection techniques used on brazed joints and weldments are described.
Introduction
Authors: Collins C. G.
Published: August 2009

This Symposium on Radiation Effects and Radiation Dosimetry was sponsored by ASTM Committee E-10 on Radioisotopes and Radiation Effects as part of a continuing effort to foster communication and promote development in these two related fields. Although both radiation effects and radiation dosimetry are more than a half-century old, they are relatively new and rapidly developing technologies when viewed from the standpoint of the requirements posed by the development of nuclear energy. In view of the pertinence of these developments to the Society's interests and of the increasing need for testing standards, Committee E-10 has considered the sponsoring of symposia on these two fields one of its prime responsibilities. The present symposium was the fifth presented before the Society in recent years. In the organization of the symposium, an attempt was made to obtain information representative of the trend in the past few years to analysis and experimental verification of principles and to critical examination of accepted notions. The five papers in the radiation effects category include two that present recent experimental data on fuel elements and steels and three that deal with parameters that influence the production of effects. One of the few references to effects dependent on the rate of irradiation is included in the description of the performance of Enrico Fermi fuel pins; the results are interpreted, in part, in terms of an effect of rate of fissioning. A second paper describing experimental work presents extensive data on the Charpy V and drop-weight test transition temperatures of irradiated steels and weld metals. In addition to establishing that the effects measured by the two tests are related in much the same manner in irradiated and unirradiated steels, evidence is also presented of considerable discrepancy in the results from exposures in different reactors at the same dosage of fast neutrons (E ≥ 1 Mev). These discrepancies confirm the doubts that have existed on the adequacy of dosages in terms of (≥1 Mev) neutrons as a true measure of exposure. This same problem is considered theoretically in two papers on the importance of the neutron spectrum in producing effects in non-organic solids. It is concluded in the first of these papers that the spectrum must be defined in order to predict adequately the production of interstitial-vacancy pairs. Extensive computations are presented in the second paper to show the variation in the number of displaced atoms produced in steel by different neutron spectra and it is indicated that neutrons of energies less than 1 Mev are a significant factor in damage to metals. The other paper of this group also considers the role of molecular weight, molecular structure, sample thickness, and reaction mechanisms such as diffusion in radiation stability of organic polymers.
Irradiation Testing of Enrico Fermi Prototype Fuel Pins in the CP-5 Reactor
Authors: Silliman M. A. , Shoudy A. A. , Huebotter P. R. , Blessing W. G.
Published: August 2009

Three Enrico Fermi prototype fuel pins have been irradiated in the CP-5 reactor to average burnups of 0.27, 0.58, and 0.85 per cent of the total atoms fissioned in the uranium — 10 per cent by weight molybdenum fuel alloy. The purposes of the tests were to study the radiation stability of the full-size pins under environmental conditions similar to those expected in the Enrico Fermi Fast Breeder Reactor, and to verify the swelling-temperature-burnup relationships established in a previous capsule irradiation program conducted in the Materials Testing Reactor (MTR). Through correlation of diameter measurements, temperature, and postirradiation metallographic analysis, it is concluded that the radiation stability of the alloy is heavily dependent on the metallurgical condition of the material. The γ phase, stable above 1060 F, resists radiation more effectively than the α + δ phases, which are thermally stable at temperatures less than 1045 F. Data from the CP-5 program suggest a more severe burnup limitation on this alloy than was previously concluded on the basis of the MTR results. The disparity is believed to be due to the influence of the fission-rate parameter on the microstructure of the material during irradiation. Fission events, if they occur with sufficient frequency, maintain the γ phase at temperatures below 1060 F. If the critical rate is not attained, the alloy will transform thermally in accordance with the uranium-molybdenum equilibrium diagram and the macroscopic temperature of the material.
Effect of Neutron Irradiation on Charpy V and Drop-Weight Test Transition Temperatures of Various Steels and Weld Metals
Authors: Hawthorne J. R. , Steele L. E.
Published: August 2009

Charpy V-notch and drop-weight specimens were used to determine changes in transition temperature for various steels and weld metals irradiated in different nuclear and thermal environments to integrated fast neutron flux exposures to 2 × 1019 nvt (<1.0 Mev). The Brookhaven Graphite Reactor, the Oak Ridge Low-Intensity Test Reactor (LITR), and National Reactor Test Station Materials Testing Reactor (MTR) were used for the irradiations at temperatures under 200 F and at 575 F. Irradiations to integrated fast neutron flux levels of 5 × 1018 nvt effected 40 to 100 F shifts in transition temperature. Increasing the irradiation temperature from 200 to 575 F significantly decreased the radiation-induced damage. Transition temperature shifts in the order of 250 F were developed in materials irradiated at temperatures less than 200 F to an integrated fast neutron flux dosage of 1 × 1019 nvt. Postirradiation heat treatment revealed that a recovery of properties may be obtained by annealing. Comparison of Charpy V and drop-weight nil-ductility transition temperature shifts for 20 irradiation experiments demonstrated excellent correspondence in the evaluation of irradiation effects by these two test methods.
Radiochemistry and Mass Spectrometry in Fuel Depletion Studies
Authors: Hudgens J. E.
Published: August 2009

Mass spectrometers designed for isotopic analyses on small samples of fuels for neutronic reactors have been used for fuel depletion studies. The design details of these instruments and the mathematical basis for data treatment are described. Studies have been performed utilizing radiochemical methods for fuel depletion determinations. Gamma ray spectrometry and radiochemical separations have been used to determine the total number of fissions induced in irradiated specimens. By combining radiochemical and mass spectrometric techniques a description of the isotopic changes in fuel specimens was obtained.
High-Intensity Gamma Ray Dosimetry
Authors: Hale D. , Johnson D. R. , Dec S. M. , Coss J. R. , Sessoms O. V. P. , Hemmig P. B. , Rice W. L. R. , Brocklehurst R. E.
Published: August 2009

In addition to the gamma ray highintensity dosimetry systems discussed in Nucleonics in October, 1959, several special systems have been utilized by this laboratory in studying radiation effects on materials. A few of these systems are discussed below in the belief that they offer certain advantages in cost or performance and may be of interest to other workers in the field. Since almost any material that exhibits a measureable and reproducible change in physical or chemical properties can be used as a dosimeter, the usefulness of such systems depends on a thorough knowledge of these changes. The foremost requirement, that property changes be accurately measureable, limits their usefulness to limited regions of integrated dose. The requirements for approximating the energy sensitivity, volume, and density of the test materials must also be considered when the energy spectra of the source is unknown or when self-absorption characteristics of the material sample are believed significant. In addition to using dosimetry that approximates the test materials in effective atomic number and sample self-absorption characteristics, more standard techniques such as graphite ion chambers and ferrous-ferric chemical dosimeters are used for comparison with other facility results when possible. At high dose rates or high total dose applications only a few satisfactory systems are available. The use of more than one system is of value for reliability as well as for diagnosis of dose rate and energy sensitivity effects which may influence results obtained with the test material. Integrated dose systems generally involve measurement of some chemical change in a material and are most useful in performing two functions. The first is as a monitor of the total radiation received. This is particularly valuable in sources having a rapidly changing dose rate, especially when the dosimeter system is chosen to have a spectral response similar to the test specimen. The other function is as an absolute calibration of dose or dose rate.
A Solid State Bragg-Gray Cavity Chamber
Authors: Ritz Victor H. , Attix Frank H.
Published: August 2009

An attempt has been made to construct the solid state analogue of a Bragg-Gray cavity ionization chamber. Thin layers of materials sensitive to radiation have been placed between walls of carbon, aluminum, copper, tin, or lead. Two types of sensing agents have been employed: thin layers of anthracene whose ultraviolet-induced luminescence degrades upon irradiation, and 6-μ thick polyethylene terephthalate (Mylar) films whose optical density at 3250 Å increases upon irradiation. Results in a cobalt-60 gamma ray field with the anthracene disagree sharply with theory, while the Mylar film yields excellent agreement (±5 per cent) with theory. A preliminary attempt to discriminate between the fast neutron and gamma ray dose in a nuclear reactor has been unsuccessful.
Measurement of the Energy Absorbed from Pile Neutrons
Authors: Binder D. , Bopp C. D. , Towns R. L.
Published: August 2009

The energy absorbed by materials in a pile may be measured directly by calorimetric methods. In view of the difficulties of in-pile calorimetry, however, it is of interest to develop other methods of measurement. Neutron threshold and resonance reactions provide a means for estimating the neutron spectrum in the pile and may be used to calculate the energy absorbed from neutrons. In order to test the accuracy of this method, threshold and resonance detectors were placed in various positions in the Oak Ridge National Laboratory Graphite Reactor and the results were compared to calorimetric measurements. Two experimental holes in the reactor were used, hole 19 and hole 51. Hole 19 is a 2-in. circular hole in the graphite moderator running transverse to the cylindrical fuel elements, which are spaced 8 in. apart in a square lattice. Hole 51 is a 4 by 4-in. hole also running transverse to the fuel rods and contains a cylinder of enriched uranium. The uranium cylinder or “converter” increases the flux of fission neutrons while depressing the thermal neutron flux.
Neutron Dosimetry for Materials Irradiation Studies
Authors: Steele L. E. , Hawthorne J. R.
Published: August 2009

The correct interpretation of radiation effects upon materials depends upon accurate knowledge of neutron exposures. An analysis of the problems associated with neutron dosimetry for materials irradiation experiments in research reactors is presented along with a discussion of neutron flux data as a factor in the experimental environment. Some of the problems presented include: choosing the best monitors, interpreting preliminary neutron flux surveys, measuring and interpreting flux levels under changing reactor conditions, and using flux data in the analysis of radiation effects. These problems are discussed, citing examples from practical experience in the Argonne CP-5 Reactor, the Brookhaven Graphite Reactor, the Oak Ridge Low-Intensity Test Reactor (LITR), and the Materials Testing Reactor (MTR).
Neutron Spectrum Determinations at Low Flux Levels
Authors: Kruger Paul
Published: August 2009

Neutron flux measurements have been made (1)2 of low-level neutron sources present in several types of neutron-producing facilities. The flux levels or distribution of thermal, epithermal, and fast neutrons have been measured in radioisotope sources, spent fuel element gamma irradiation facilities, and electron linear accelerators. Sensitivities greater than 1 neutron per sq cm per sec have been achieved for thermal neutrons. Neutron flux measurements may be made by several methods (2). Foil activation (3) is a convenient and simple technique. The foils containing materials of known cross-section are exposed to the neutrons, and the flux determinations are made by measurement of the induced activities in the irradiated foils. This technique is widely used for measuring neutron fluxes and spectra in nuclear reactors and critical facilities where the neutron fluxes are large (106 to 1014 neutrons per sq cm per sec). To measure neutron fluxes of smaller magnitude, such as those found in isotope sources, gamma irradiation facilities, or outside reactor shielding (¼106 neutrons per sq cm per sec), special foil dosimetry techniques or counting methods are required to obtain sufficient sensitivity for the radioactivity measurements. The theoretical and experimental considerations for neutron detectors of high sensitivity and several programs in which these detectors were used are discussed.
Permeability of Materials Under High Pressures and at Various Temperatures
Authors: Epstein George , Gary W. W.
Published: August 2009

Reinforced plastics and other materials used in rockets, missiles, and pressure vessels are frequently subjected to high-pressure differentials, perhaps as high as several thousand pounds per square inch. It is often essential that the pressurizing medium, whether it be air, water, or propellant combustion gases, not be permitted to penetrate into or pass through the material. In many cases high temperatures may also be present. A test device was therefore required to establish the serviceability of various materials under such conditions. After considering the theoretical and practical aspects of the problem, a small pressure vessel was designed and fitted with the necessary accessories to provide an apparatus (the Aerojet Permeability Cell) capable of measuring the permeability rates of solid materials under gas pressures up to at least 5000 psi at temperatures up to about 500 F. Various materials including reinforced-plastic laminates have been so tested; and in some cases, suitable sealants have been evaluated to reduce or prevent the flow of gas through the material.
Testing of Materials Under Ablative Conditions
Authors: King Harry A.
Published: August 2009

The development of new and superior materials for rockets and missiles is one of the most important phases of the current space program. Such development requires extensive testing under conditions that simulate actual exposure as closely as possible. A few hundred degrees difference in gas temperature, a change in gas velocity, or in chemical composition can markedly alter the resistance that a material might exhibit to a particular ablative condition. The conditions surrounding a particular missile material are generally very “unusual,” that is, temperatures of 5000 F or more, gas velocities of Mach 10 or higher, highly oxidizing atmospheres, and other equally difficult conditions. Previous attempts to duplicate these “unusual” conditions in the laboratory have resulted in such expensive and space-consuming apparatus as wind tunnels, shock tubes, and complete test rocket motors. To overcome the cost, space, and power problems and to help speed up materials research and the flow of new materials to the missile industry, the Aerojet-General Corp. began a program to determine whether simple, inexpensive equipment could be developed or designed to give meaningful test results. With such equipment, it was hoped that new and superior materials would be developed at a substantially faster rate than at present.
Photographic Technique of Surface Temperature Measurement
Authors: Siviter James H.
Published: August 2009

In recent years there has been a great deal of interest in the development of devices capable of measuring elevated surface temperatures. Tests conducted in high-temperature facilities depend upon accurate temperature measurements for their intelligent interpretation. Thermocouples are generally used wherever possible but in many instances another method is required. Optical pyrometry has also been used extensively in industrial and laboratory applications. The absolute accuracy is generally not as good as with thermocouples, but this is a relatively minor consideration at elevated temperatures. The study of ablation and refractory materials has inspired the investigation of a new technique of determining surface temperatures and intricate temperature profiles. Attempts have been made to install thermocouple probes in ablation materials, but this is restrictive since probes tend to alter the homogeneity of the material and cause erosion around the probes. Thermocouples embedded in the material would not effectively measure the surface temperature because of the extreme temperature gradient through an ablation material. The general requirements for a surface temperature measuring technique demanded by the ablation program could be described as follows: It was desired to measure the absolute surface temperature. Secondly, a system was needed that would be capable of determining surface temperature profiles over a large area. A survey of commercially available equipment did not reveal any device that would be entirely satisfactory without considerable modification. Preliminary studies of various methods of temperature measurement indicated that a photographic technique offered the best all-around possibilities.
Testing of Reinforced Plastics Under Simulated Re-Entry Conditions
Authors: John R. R. , Bade W. L.
Published: August 2009

The electric-arc air heater or plasma jet is the only laboratory tool available for studying the steady-state ablation characteristics of materials under simulated hypersonic re-entry conditions. A procedure which has been used for the calibration of a subsonic plasma jet facility is described. The calibration procedure is a method for determining the aerodynamic and thermodynamic parameters characterizing the interaction of the subsonic jet of arc-heated air with the surface of a flat-faced material specimen. Values of the air enthalpy, pressure, velocity gradient, shear-stress gradient, and heat flux at the stagnation point on the specimen are estimated using the calibration procedure. The estimated values of stagnation pressure and velocity gradient agree with experimental values based on pressure distribution measurements. Heat flux values predicted on the basis of laminar boundary-layer theory and shock-tube measurements are found to agree with heat-transfer rates measured using a constant-flow water calorimeter. The aerodynamic, thermodynamic, and chemical conditions in the plasma jet are compared with those characteristic of hypersonic re-entry. It is shown that the plasma jet is capable of exact simulation of a wide range of re-entry conditions.
Handling and Analysis of Routine Water Samples in Volume
Authors: Sussman S. , Portnoy I. L. , Jacobson J.
Published: August 2009

The need for analyzing more than 59,000 water samples annually as part of water treatment control in thousands of systems has led to the development of an efficient analytical laboratory operation. To attain the lowest costs consistent with the accuracy required, some of the principles of mass production have been adapted to the laboratory facilities and operations. This paper describes the sample handling procedures, physical layout, and specialized equipment used. It also discusses the techniques used to ensure necessary standards of accuracy.
Analytical Methods and Instrumentation for Determining Cyanogen Compounds
Authors: Lancy L. E. , Zabban Walter
Published: August 2009

This paper discusses the meaning of certain well-known methods of analysis for cyanogen compounds in the evaluation of treatment requirements and results of treatment of industrial wastes. The experience of the authors with the use of instrumentation for the determination of cyanides and for the measurement and control of the extent of treatment in the oxidation of cyanides by chlorine or hypochlorite reagents is also described. Some methods of analysis for cyanates are reviewed.
Two Methods for the Determination of Nitrates in Water
Authors: Goldman Eugene
Published: August 2009

This reappraisal of the phenol-disulfonic-acid method for the determination of nitrate shows that it can be adequate if procedural pitfalls are recognized and avoided. The determination of nitrate ion based on its absorption of ultraviolet radiation is also discussed. Results obtained using the ultraviolet absorption method are apparently equivalent to those found by the phenol-disulfonic-acid method based on analysis of a variety of water types. The two methods are discussed and the results obtained are compared.
Preliminary Evaluation of Some Luminescent Phosphors for Use in Viewing Screens in the Electron Microscope
Authors: Morenski R. P.
Published: August 2009

A comparison was made of several compounds used as viewing screens for electron microscopes. This study shows that zinc silicate gives better resolution, contrast, and only slightly less brightness than zinc sulfide, the compound most commonly used.
Investigation of the Substructure of Stainless Steel After Explosive Shock Deformation
Authors: Inman M. C. , Murr L. E. , Rose M. F.
Published: August 2009

Shock-induced lattice faults have been studied in stainless steel subjected to explosive deformation pressure pulses in the range 120 to 425 kilobars. It has been found that the deformation faults lie on {111} lattice planes. Selected area diffraction also indicates that the faults possess an imperfect but pronounced twin orientation with respect to the matrix. The fault density deduced from electron micrographs increases almost linearly with peak shock pressure and exhibits a direct correlation with microhardness. Evidence is also produced to show that there is a transition from single stacking faults to imperfect twin faults with increasing shock pressure.
Grain-Boundary Carbides in High-Speed Tool and Hot-Work Die Steels
Authors: Banerjee B. R. , Capenos J. M. , Hauser J. J.
Published: August 2009

Rapid etching and clear delineation of prior austenite grain boundaries are characteristic of tool steels upon rapid quenching from sufficiently high austenizing temperatures and of hot-work die steels upon arrested quenching. In this study, two tool steels (M2 and M10 types) and a hot-work die steel (H21 type) were heat treated under a variety of austenizing conditions and examined by extraction replica electron microscopy. In each case, the grain-boundary delineation observed under light metallography was associated with the presence of discrete carbide particles. The presence of these carbides at grain boundaries accelerates the etching rates and delineates the boundaries at the lower scale of resolution in light metallography. The various boundary carbides were identified, and the carbide-precipitation kinetics were quantitatively related to interstitial supersaturation in the alloy. An interesting observation was the presence of M2C as grain-boundary carbides and as residual carbides in the high-speed tool steels.
Microstructural Alterations in Rolling Contact Fatigue
Authors: King A. H. , O'Brien J. L.
Published: August 2009

Stress-induced, structurally altered regions of ball and roller bearings were examined by transmission electron microscopy. The sectioning procedure is described in detail. A dark-etched region on roller bearings of carburized 4620 steel contained banded areas which had little in common with the microstructure of the martensite elsewhere. These lined-up areas ranged from a few to ten square microns. Electron diffraction patterns of the deformed areas exhibit arcing, but it is uncertain whether these regions give a distinctive pattern. Electron micrographs indicate that light-etched areas on 52100 steel ball bearings have a structure similar to the dark-etched regions on the other bearings. Observable precipitates do not form at tempering temperatures below 900 F. Electron diffraction patterns do not have spots which identify these microbands. X-ray studies, currently in progress, should indicate whether or not the microbands have a preferred orientation.
Effects of Salt Atmosphere on Crack Sensitivity of Commercial Titanium Alloys at 600 to 900 F
Authors: Donachie M. J. , Danesi W. P. , Pinkowish A. A.
Published: August 2009

Creep tests were performed on titanium alloy tension specimens that had the gage length coated with salt. Three alloys, Ti-6A1-4V, Ti-8Al-lMo-lV, and Ti-2.5Al-lMo-10Sn-5Zr, were tested for 100 hr at temperatures above 600 F. Test results indicate: (1) all titanium alloys tested susceptible to stress corrosion, (2) salt causes cracking but does not cause catastrophic failure unless threshold stress is exceeded, (3) the degree of susceptibility is time dependent, and (4) degree of susceptibility decreases with decreasing aluminum content for temperatures above 600 F.
Chemical and Physical Mechanisms of Salt Stress-Corrosion Cracking in the Titanium 8-1-1 Alloy
Authors: Logan H. L. , McBee M. J. , Bechtoldt C. J. , Sanderson B. T. , Ugiansky G. M.
Published: August 2009

Stress-corrosion tests were performed on hollow cylinders and sheet-metal specimens of Ti-8Al-1Mo-1V in contact with solid sodium chloride or synthetic sea-water salt. Specimens were heated to 750 F and subjected to a 73,500 psi tensile stress. Specimens failed in times as short as 18 hr. The hollow specimens were evacuated and then filled with oxygen or argon. No cracking occurred unless oxygen or water vapor was present. Cracking was also introduced in specimens preoxidized for about 65 hr and coated with sodium chloride in an inert atmosphere under the same condition of temperature and stress. The authors propose that chlorine diffuses down through a stress, and probably an oxygen concentration gradient reacts with the metal to destroy atomic bonds and produce stress corrosion. Specific reactions, however, have not yet been determined. X-ray diffraction studies of corrosion products indicate that the usual oxides of titanium are present along with an unidentified phase that may be formed by reaction between sodium chloride, oxygen, and the alloy.
Man-Rating Provisions of the Boeing 40- by 50-Foot Space Chamber
Authors: VanBronkhorst John , Yerkes J. W.
Published: August 2009

The man-rating features of the 40-foot diameter by 50-foot space environment chamber at The Boeing Co. facility in Kent, Wash., are described. This chamber was designed to allow the testing of large, manned, pressurized spacecraft in real-time simulation of earth-orbiting and deep-space missions. Key features pertaining to manned occupancy, including structural design, pumping systems, repressurization systems, controls, monitoring and rescue provisions, and biomedical training and treatment are described.
Introduction
Authors: Craig H. Lee
Published: August 2009

A recent survey by ASTM Committee G-1 revealed that nearly one hundred laboratories are engaged in stress corrosion testing. This survey was part of a task group effort to determine the state-of-the-art concerning stress corrosion testing, organized into three areas: specimen design; test environments and duration; and data evaluation and reporting. The committee decided to provide a forum at which current practices would be presented and discussed by those active in the field. Papers were solicited from engineers and scientists who use these tests for specification purposes, for material selection guides, and for design and use criteria. Theoretical papers were included where the theory was shown to influence test methodology. The theme of the conference was the development of reproducible, standardized test methods. Nearly all structural metals were covered: high strength steels, stainless steels, and alloys of aluminum, copper, magnesium, and zirconium. Some new methods were fully discussed, including the precracked cantilever beam and tests on joints, such as bolts and weldments.
Influence of Stress and Temperature on Short-Transverse Stress Corrosion Cracking of an Al-4.2Zn-2.5Mg Alloy
Authors: Helfrich W. J.
Published: August 2009

Stress corrosion cracking of an age-hardened Al-Zn-Mg alloy (7039) subject to continuous immersion in a 1 N NaCl solution was studied at stresses of 5 to 55 ksi and temperatures of 30 to 100 C and found to be an activated process. The rate, r, of stress corrosion (proportional to the inverse failure time) can be expressed as: r=r0exp{−[Q*(O)−sV*]/RT} where Q* (O) is the activation energy in the absence of stress, s, and V* is the activation volume. Q* (O) has a value of 20 ± 0.8 kg∙cal/mole, and V* is approximately 28 to 34 cm3/mole for applied stresses of 25 ksi or higher. It is suggested that the rate-determining step in the stress corrosion of 7039 involves anodic dissolution of MgZn2 at grain boundaries. The mechanism of stress corrosion cracking is discussed with reference to previously derived models.
A Comparison of Three Precracked Specimens for Evaluating the Susceptibility of High-Strength Steel to Stress Corrosion Cracking
Authors: Beachem C. D. , Brown B. F.
Published: August 2009

The susceptibility of AISI 4340 steel to stress corrosion cracking in dilute NaCl solution is examined using the center-cracked and part-through-crack tension specimens and the edge-cracked cantileverbeam specimen. The data are treated in terms of linear elastic fracture mechanics. It is found that all three types of specimens can be used to determine the value of the plane-strain stress-intensity factor above which cracking will occur in the presence of this aggressive environment.
Influence of Environment on Crack Propagation Characteristics of High-Strength Aluminum Alloys
Authors: Mulherin J. H.
Published: August 2009

The stress corrosion behavior of four alloys of aluminum has been investigated. Using cantilever-loaded fatigue-cracked specimens, the crack propagation characteristics of 7178-T6, 2014-T6, 2024-T351, and 7075-T6 aluminum alloys were determined. The results are interpreted in terms of fracture mechanics parameters. Where susceptibility to stress corrosion exists, the rate of crack propagation is dependent upon stress intensity and environment. A method is also presented to obtain threshold values of stress intensity for stress corrosion attack with minimal experimental effort. The aqueous environments used were immersion in distilled water, immersion in 3 1/2 per cent sodium chloride, and alternate immersion in salt solution and air. The cantilever technique is evaluated and the results compared to other testing methods.
Stress Corrosion Cracking of High-Strength Bolting
Authors: Lin C. S. , Laurilliard J. J. , Hood A. C.
Published: August 2009

Exposure of high-strength steel bolts (260,000 psi) to the natural environments of temperature changes, moisture, and salt air have resulted in a number of stress corrosion cracking failures. Cadmium plating of the bolts has not prevented these failures. This paper presents a study of bolts made from H-11, 4340, and maraging steel heat treated to several strength levels. The authors have adopted the 3 1/2 per cent NaCl solution, intermittent exposure test to high-strength bolting and have used it as a basis for comparison of bolt life. The influence of thread rolling sequence and applied and residual stresses, as well as electroplated and zinc primer coatings, were investigated. The results indicate that a H-11 high-strength steel bolt with threads rolled after heat treatment will fail in the shank. Cadmium plate with an undercoat of nickel increases the life by five to seven times. The comparison of steel types shows the maraging steel (300) to have the best life of the three alloys but not sufficient to overcome the environmental effects.
Resistance of Ferritic Stainless Steels to Stress Corrosion Cracking
Authors: Bond A. P. , Marshall J. D. , Dundas H. J.
Published: August 2009

Stress corrosion cracking tests were carried out on 0.020-in.-diameter wires under dead-weight loading in boiling solutions of MgCl2, Ca(NO3)2, and NaOH. The T430 and T434 ferritic stainless steels were immune to stress corrosion cracking in MgCl2 under conditions which caused various austenitic grades to fail in 6 to 46 min. Pitting corrosion in MgCl2 reduced the cross-sectional area of the ferritic steel specimens to the extent that they could not support the load, and they failed in a ductile manner. Stressed specimens of ferritic stainless steels did not fracture in Ca(NO3)2 or NaOH even after heat treatments which led to intergranular corrosion. Corrosion potential measurements were made on the stressed specimens and correlated with various stages in the stress-corrosion cracking process.
A Proposed Mechanism for the Stress Corrosion Fracture of a Copper-Beryllium Alloy
Authors: Sylwestrowicz W. D.
Published: August 2009

Polycrystalline specimens of a copper-beryllium alloy (1.8 per cent Be) were bent and exposed to an ammonia atmosphere. Two lots of polycrystalline material of similar chemical composition but of different grain size and distribution of segregates were investigated. Specimens were subjected to different values of plastic deformation and humidity conditions. Plastic deformation appears to be an essential factor in stress corrosion fracture. The importance of humidity conditions was emphasized by the results obtained. Both modes of fracture, transcrystalline and intercrystalline, were observed. It was found that the distribution of segregates determines which of these two modes of fracture will occur. A mechanism of stress corrosion fracture in a copper-beryllium alloy is proposed.
Critical Species in Stress Corrosion Phenomena
Authors: Pugh E. N. , Westwood A. R.C.
Published: August 2009

Consideration has been given to the identification of the critical species in several stress corrosion systems. It is shown that in the α-brass/aqueous ammonia system, cupric complex ions of the type Cu(NH3)n2+ play a controlling role in the cracking process. Complex ions are also found to constitute the critical species in the embrittlement of silver chloride in certain aqueous environments. In the case of materials such as stainless steels and magnesium and aluminum alloys, which undergo stress corrosion cracking in chloride environments, the critical species may be the chloride ion itself or metal-chloride complexes. Attention is given to both the role of the critical species in the mechanisms of failure and the practical significance of these findings to stress corrosion testing. It is suggested that more attention to the chemistry of environments which cause stress corrosion cracking, with particular regard to the identification of the critical species, could be of significant practical value.
Circulating Autoclave System for Stress Corrosion Cracking Studies
Authors: Staehle R. W.
Published: August 2009

A circulating autoclave system has been constructed and operated in which time-to-breaking can be determined exactly at temperatures to 700 F, pressures to 5000 psi, a wide range of stresses, various concentrations of dissolved gases and ionic species, and for a large number of specimens exposed simultaneously. Preliminary experiments have studied commercial and specially melted iron-nickel-chromium alloys. Results have confirmed already established trends for the effect of environment and alloy composition at 500 F.
Stress Corrosion Cracking Rates of a Nickel-Brass Alloy Under Applied Potential
Authors: McKinney Nancy , Hermance H. W.
Published: August 2009

A method was developed to test the susceptibility of nickelbrass alloys to stress corrosion cracking in the presence of nitrates or other salts. A wire of the alloy under test was stressed, and an electrical leakage path was provided to a cathode by a filter paper impregnated with the electrolyte being studied. Stresses, potentials, salt concentrations, relative humidities, and time were varied to evaluate these factors. In the case of ASTM Grade D nickel-brass alloy, using ammonium nitrate as the electrolyte, the rate of crack penetration increased with increases in the salt concentration in the leakage path, the applied stress, relative humidity, and temperature. There was no direct correlation with the applied potential. Other hygroscopic nitrates such as zinc, and to a lesser degree calcium and copper, also caused stress corrosion cracking. Chlorides and sulfates were ineffective under conditions in which nitrates produced cracking. From the data obtained, the expected failure times of nickel-brass parts at average ambient temperature and humidity could be estimated.
Reporting and Evaluating Stress Corrosion Data
Authors: Sprowls D. O.
Published: August 2009

Susceptibility of a metal to stress corrosion implies a greater deterioration of its mechanical properties through the simultaneous action of a static stress and exposure to a corrosive environment than would be produced by the combined effects of each factor operating separately. In recent years this point of view on stress corrosion and stress corrosion cracking (the ultimate in stress corrosion) has become widely recognized. However, confusion still exists, with the result that some work is published that has little value because of the poor design of testing procedure. It is still sometimes erroneously assumed that failure of a specimen under stress corrosion test conditions suffices to demonstrate susceptibility to stress corrosion cracking. This conclusion is unjustified, for the specimen may have become so weakened by corrosion, even without any acceleration by stress, as to fail under the applied load. Thus, it is most essential to select techniques (type of specimen and method of loading, test medium and period of exposure) that produce failure that is purely the result of stress corrosion cracking. Because of the marked effect that test procedure can have upon ordinary criteria, such as specimen life, percentage of specimen survival, threshold stress, etc., investigators should report details of procedure and technique as well as detailed data along with their analysis of the results. This is necessary to enable the reviewer to adapt the information to his need and to make possible a reanalysis of the data by some method that may be developed in the future.
Stress Corrosion Testing of 7079-T6 Aluminum Alloy in Various Environments
Authors: Lifka B. W. , Sprowls D. O.
Published: August 2009

Stress corrosion cracking of certain 7079-T6 aluminum alloy aircraft structures involving sustained tensile stress acting in an unfavorable grain direction has occurred sometimes in surprisingly mild environments. The resistance of short-transverse specimens of 7079-T6 products has been evaluated at different levels of applied stress in several different seacoast and inland industrial atmospheres. It was found that the atmosphere was more critical than the generally accepted alternate-immersion test using 3.5 per cent sodium chloride. The results of the outdoor tests are correlated with eight accelerated exposures; and consideration is given to the most suitable laboratory stress corrosion test environment for this alloy. A detailed analysis of the constant deformation methods of stressing is included.
Introduction
Authors: Newhouse D. L.
Published: August 2009

Temper embrittlement has been one of the perennial problems of physical metallurgy, accompanying the use of alloy steels for a number of decades. Practical solutions have been found for particular problems involving embrittlement, better methods of measuring temper embrittlement have been developed, and a great deal has been learned about this complex problem, but real understanding of the fundamental mechanisms involved has been elusive. Current trends in the design of heavy structural components, such as large pressure vessels and turbine-generator rotors, require increased size, more massive sections, higher stresses, and, in some cases, increased operating temperatures. At the same time, advances in understanding of fracture mechanics tend to require concurrent improvement in fracture toughness. Steels with higher hardenability are needed to attain the required through-section fracture toughness at the higher yield strengths needed for such components. However, temper embrittlement is assuming increasing importance as an obstacle inhibiting progress in the design of such heavy components. The higher-alloy steels required for through-section hardenability and toughness tend to be much more susceptible to temper embrittlement than the lower-alloy pearlitic steels. Larger ingots imply greater segregation of alloying and embrittling elements, and more massive sections must be cooled more slowly through the temperature range of embrittlement. Susceptible steels operated for long times within the temperature range of embrittlement, 350 to 575 C, may embrittle to a surprising degree; the notch toughness transition temperature may increase by hundreds of degrees. The possibility of such embrittlement must be considered in every phase of design, heat treatment, and operation if unexpected deficiencies or losses in fracture toughness are to be avoided. The technical and economic value of effective control of temper embrittlement in high hardenability steel is very great.
Stress-Relief Embrittlement of High-Strength Quenched and Tempered Alloy Steels
Authors: Rosenstein A. H. , Asche W. H.
Published: August 2009

An investigation was undertaken of the time-temperature-embrittlement relationships of two high-strength quenched and tempered steels. Optimum stress-relief treatments were developed which incorporate the maximum reduction in residual stress accompanied by the minimum increase in transition temperature. It was determined that stress-relief embrittlement in Steel A (5Ni-Cr-Mo-V, 140 ksi yield strength) is most severe in the 900 to 1000 F temperature range, and that Steel B (3Ni-Cr-Mo, 100 ksi yield strength) is not significantly embrittled by stress relief. The optimum stress-relief treatments for Steels A and B are obtained by heat treatment at as high a stressrelieving temperature as possible. The maximum stress-relieving temperature is limited to that which will not result in loss of yield strength.