Download or read book The Role of Carburization in Gun Barrel Erosion and Cracking written by C. C. Morphy and published by . This book was released on 1981 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: The subject program is part of a continuing effort to identify distinct mechanisms that contribute to gun barrel wear and erosion. The chemical effect of a carburizing atmosphere in a gun tube was the main topic for investigation in this program. Experiments were conducted in the Shock Tube Gun (STG), a ballistic compressor, designed and developed by Calspan Corporation. This facility can compress mixtures of pure gases to simulate propellant gas flow condtions and cycle time experienced in large caliber guns. Test were conducted with a mixture of argon and nitrogen to delineate the threshold of simple melting erosion which served as a chemical inert baseline. Progressive substitution of carbon monoxide for nitrogen in the mix quantified the carburizing effect as a function of CO concentration. Subsequent tests were conducted with a gas mixture containing carbon monoxide, argon and helium to measure the carburizing effect as a function of cycle time. The basic carburizing effect was observed to be a shift in the erosion threshold to less severe convective heating conditions in response to surface chemistry. The magnitude of the shift appeared to be directly proportional to heating cycle time.
Download or read book The Role of Oxygen in Gun Barrel Erosion and Cracking A Shock Tube Gun Investigation written by and published by . This book was released on 1980 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments to determine the individual contributors to gun barrel erosion in an oxidizing atmosphere were conducted in the Shock Tube Gun (STG), a ballistic compressor, designed and developed by Calspan Corporation. This facility can compress mixtures of pure gases and can generate flow conditions and cycle times similar to those experienced in large caliber guns. Tests were conducted with a mixture of argon and nitrogen to define the threshold erosion for an inert baseline. Small concentration of oxygen were substituted for nitrogen in the mix to quantify the oxidation effect. Subsequently, tests were conducted with various gas mixtures containing carbon dioxide, which dissociates to produce oxygen when compressed to high temperatures. The basic oxidation effect was observed to be nearly linear increase in erosion with oxygen concentration. A corresponding shift in the erosion threshold to less severe convective heating conditions was observed in response to surface chemistry. A similar effect was observed for carbon dioxide mixture where erosion was correlated in terms of the equilibrium concentration of oxygen at peak pressure. Surface cracking was observed and found to be most severe near the erosion threshold where the oxide layer was thickest. A white layer was observed in tests with oxygen in the absence of carbon dioxide.
Download or read book Technical Abstract Bulletin written by and published by . This book was released on 1981 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Army Ordnance written by and published by . This book was released on 1924 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book First Computer Code for Predicting Thermochemical Erosion in Gun Barrels written by and published by . This book was released on 1996 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: An update is provided for the previously-presented gun barrel thermochemical erosion modeling code. This code addresses wall degradations due to transformations, chemical reactions, and cracking. As a predictive tool, it provides analysis and design information that is either unattainable or expensive by experiment. Single- or multiple-shot comparisons can be made of either the same gun wall material for different rounds, or different gun wall materials for the same round., this complex computer analysis is based on rigorous scientific thermochemical erosion considerations that have been validated in the reentry nosetip and rocket nozzle/chamber community over the last forty years. A gun system example is used to illustrate the five module analyses for chromium and gun steel wall materials for the same round. The first two modules include the somewhat modified standard gun community XNOVAKTC interior ballistics and BLAKE nonideal gas thermochemical equilibrium codes. The last three modules, significantly modified for gun barrels, include the standard rocket community two-dimensional kinetics!mass addition boundary layer (TDK/MABL), gas-wall thermochemistry TDK/CBT), and wall material ablation conduction erosion (MACE) codes. These five analyses provide thermochemical ablation, conduction, and erosion profiles for each material as a function of time, travel, and rounds. For the gun system example, at two axial positions, with cold and hot firing rates. predictions of rounds required to achieve 0.040-inch wall loss are made for cracked and uncracked 0.005-inch chromium plated A723 steel and A723 steel alone. Thermochemical erosion increases by a factor of about 2.0 from cracked chromium plated A723 steel to A723 steel alone. For a given%wall, thermochemical erosion decreases by a factor of 1.4 from the hot to the cold firing rates.
Download or read book Erosion in 7 62mm Machine Gun Barrels written by William T. Ebihara and published by . This book was released on 1970 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: Metallurgical analysis was conducted on 7.62mm machine gun barrels, in the chromium-plated and unplated conditions, to describe the erosion process. The chronological analysis involved the examination of severly eroded gun barrels as well as those subjected to test firings of 1 to 3000 rounds. Inherent defects in the form of cracks were noted in the chromium plate prior to firing. These cracks were extended to the chromium-steel interface as early as the first round; thus the underlying steel was exposed to the reactive environment. Continued firing resulted in the propagation of these cracks into the steel substrate followed by crack-branching. Branching proceeded until linkup was achieved, which resulted in the removal of chromium plate steel fragments. The factors considered to be responsible for crack extension include gaseous and liquid metal reactions. The type of erosion found in unplated steel gun barrels was in contrast with that of the plated barrels in that substrate-cracking was delayed and land wear occurred much earlier in the firing sequence.
Download or read book CAB Current Awareness Bulletin written by and published by . This book was released on 1981 with total page 456 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Characterization of Bore Surface Layers in Gun Barrels written by and published by . This book was released on 1984 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt: Specimens containing white layers were taken from the bore surface of the unplated and chrome plated fired gun tubes. These were examined metallographically and the presence of various white layers was established. The chemical and structural nature of these layers was determined by Auger/ESCA and x-ray diffraction techniques. The outermost white layer contained up to seven percent carbon and was identified as cementite - Fe3C. The subsequent white layers has approximately one percent carbon and were identified as high carbon austenite. The significance of these results is discussed in terms of solution and diffusion of carbon from burnt propellant are responsible for the formation of white layers and are the cause of erosion and cracking in the bore surface. During heating and cooling of fired gun barrels, stresses are generated by the differences in the coefficient of expansion and volume changes associated with cementite, austenite, and matrix metal phases. Cracks are produced in the white layer and are propagated in the substrate steel matrix. The high carbon- containing phases are lower melting than steel. These molten phases are eroded away by the sweeping hot propellant gases, thereby eroding the bore surface of the gun barrel. These and other results are discussed in terms of their effects on erosion and wear in the gun barrel bore surfaces.
Download or read book Gas Chemistry Effects on Gun Barrel Erosion A Shock Tube Gun Investigation written by and published by . This book was released on 1982 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: The subject program is part of a continuing effort to identify distinct mechanisms that contribute to gun barrel wear and erosion. The thermochemical effects of altering the CO/CO2 ratio of a propellant gas in a gun tube was the main topic for investigation in this program. Experiments were conducted in the Shock Tube Gun (STG), a ballistic compressor, designed and developed by Calspan Corporation. This facility can compress mixtures of pure gases to simulate propellant gas flow conditions and cycle times experienced in large caliber guns. Tests were conducted with mixture ratios of carbon monoxide and carbon dioxide that characterize the normal range of CO/CO2 ratios found in propellant gas, i.e., 2.0 to 8.1. Progressive substitution of carbon monoxide for nitrogen in the mix quantified erosion as a function of increasing Co concentration or CO/CO2 ratio. Subsequent tests were conducted with gas mixtures containing double the amount of carbon monoxide and carbon dioxide but with the same effect CO/CO2 ratio, to measure erosion as a function of absolute reactant concentration for the two gas species. The basic chemical effect was observed to be a shift in the erosion threshold to less severe convective heating conditions in response to increasing the CO/CO2 ratio above a value of 5.6. The magnitude of the shift appeared to be directly proportional to the absolute concentrations of the two reactant gases. Variation of both CO/CO2 ratio and absolute amounts of the two gases resulted in distinct changes in specimen surface characteristics, both at near threshold and above threshold flow conditions.
Download or read book Government Reports Annual Index written by and published by . This book was released on 1981 with total page 1316 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
Download or read book Erosion Modeling of the 120 MM M256 M829A2 Gun System written by and published by . This book was released on 1997 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Benet Laboratories/Software and Engineering Associates, Inc. (SEA) gun barrel erosion modeling and design code predicts wall degradation due to transformations, chemical reactions, and cracking coupled with pure mechanical erosion for the 120-man M256/MS29A2 gun system for ambient temperature-conditioned rounds. The A723 steel and 0.005-inch high contraction (HC) chromium plated/A723 steel wall materials are evaluated for erosion. This complex computer analysis is based on rigorously evaluated scientific theory that has been validated in the rocket community over the last forty years. Our gun erosion analysis includes the standard interior ballistics gun code (XNOVAKTC), the standard nonideal gas-wall thermochemical rocket code modified for guns (CCET). the standard mass addition boundary layer rocket code modified for guns (MABL), and the standard wall material ablation conduction erosion rocket code modified for guns (MACE). In addition, bore subsurface metallographic analysis and projectile-bore finite element analysis (ABAQUS) are considered. Our overall analysis provides wall material erosion predictions and comparisons of ablation, conduction, and erosion profiles as a function of time, travel (customer-selected 27. 61, 86, 130, and 201 inches from the rear face of the tube), and number of rounds to barrel condemnation. The 120-mm M256/M829A2 gun system prediction, with significant numbers of M829A2 rounds, agrees well with the wear and erosion pattern of retired M256 gun barrels.
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1981-10 with total page 1470 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Erosion in Large Gun Barrels written by and published by National Academies. This book was released on 1975-01-15 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Confronted with problems associated with the continual upgrading of field guns, reducing the number of different items in supply and lowering overall costs, the Department of the Army has need for improved methods of reducing erosion and extending the wear life of long range cannon. The National Materials Advisory Board was asked to consider all facets of this need and to make recommendations. Erosion in Large Gun Barrels assesses the nature of the bore erosion problem; identifies fruitful areas of research; assesses the state of technology of materials and methods in areas which may become significant to gun tubes of improved performance; and suggests experimental techniques, devices, and instruments and methods of reducing data to enhance the continuing coordination of the activities of the three Services.
Download or read book Unique 3 in 1 Research Development Directory written by and published by . This book was released on 1982 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Failure Analysis of Heat Treated Steel Components written by Lauralice de Campos Franceschini Canale and published by ASM International. This book was released on 2008 with total page 651 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mathematical Modeling Of Melting And Freezing Processes written by V. Alexiades and published by CRC Press. This book was released on 1992-11-01 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: Presents mathematical models of melting and solidification processes that are the key to the effective performance of latent heat thermal energy storage systems, utilized in a wide range of heat transfer and industrial applications.
