Characterization of Bore Surface Layers in Gun Barrels PDF Download
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 31
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Book Description
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.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 31
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Book Description
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.
Author: L. H. Russell
Publisher:
ISBN:
Category : Ordnance
Languages : en
Pages : 16
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Book Description
Author: A. Niiler
Publisher:
ISBN:
Category :
Languages : en
Pages : 73
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Book Description
The erosion of gun barrel bore surfaces caused by high temperature, high pressure and high velocity gases is responsible for the lives of many such barrels being wear-limited. In addition, such interactions are often accompanied by significant alteractions to the remaining bore surfaces. An ion beam analysis method has been used to characterize the depths and compositions of the outer, sub-micron layers of gun steel surfaces that have been exposed to variety of environments from several propellant/additive combinations. Correlations between the oxide/nitride concentrations in the surface layers, the propellant flame temperatures and erosive wear obtained. Scanning electron microscope observations of exposed surfaces were also made. The combined results indicate the presence of thermo-chemical erosion as well as erosion by a surface melt and wipe-off process.
Author: Woldemar W. Sveshnikoff
Publisher:
ISBN:
Category : Machine guns
Languages : en
Pages : 28
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Book Description
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 440
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Author: United States. Naval Ordnance Systems Command
Publisher:
ISBN:
Category : Weapons systems
Languages : en
Pages : 428
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Author: Murray M. Jacobson
Publisher:
ISBN:
Category : Corrosion and anti-corrosives
Languages : en
Pages : 416
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Author: Ryan Nunez
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
The purpose of this study was to assess whether a commercial abrasive firearm bore cleaner, J-B® Non-Embedding Bore Cleaning Compound (J-B®), would alter the individual characteristics of a bore when certain cleaning techniques were used. Additionally, this study also examined if toolmark origin conclusions can be changed after using J-B® to clean the bore. Based on the results of this study, it is not proven that J-B® affected the individual characteristics of the bore or that those significant changes were transferred onto the surface of a subsequently fired bullet. This preliminary study suggests that use of abrasive firearm barrel cleaners may not be able to significantly alter individual characteristics of a bore. Further research on other abrasive gun barrel cleaners as well as different barrel and ammunition types would be useful in determining how broadly this conclusion can be applied in forensic firearm examination. Additionally, the use of 3-D imaging technology such as EvoFinder or other advanced imaging techniques should be tested to determine if they provide a methodology to detect potential small changes to the surface of bullets after abrasive barrel cleaners are used to clean a bore.
Author: United States. Army Materiel Command
Publisher:
ISBN:
Category : Projectiles, Aerial
Languages : en
Pages : 290
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Book Description
This handbook presents a general survey of the principal factors affecting the flight of projectiles, and describes the methods commonly used for predicting and influencing the flight performance. The coefficients which characterize the aerodynamic forces and moments of a moving body are identified, methods for determining the coefficients applicable to a projectile having a given shape and center of gravity location are described, and the coefficients of a number of projectiles and projectile shapes are given. The use of aerodynamic coefficients in predicting stability, range and accuracy is described. The effects of variations in projectile shape and center of gravity location on range, accuracy and lethality are discussed. Some material on prototype testing and the effects of round-to-round variations in production lots is presented.
Author: Shiquan Zhou
Publisher: CRC Press
ISBN: 1351652753
Category : Science
Languages : en
Pages : 1162
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Book Description
The 2016 2nd International Conference on Energy Equipment Science and Engineering (ICEESE 2016) was held on November 12-14, 2016 in Guangzhou, China. ICEESE 2016 brought together innovative academics and industrial experts in the field of energy equipment science and engineering to a common forum. The primary goal of the conference is to promote research and developmental activities in energy equipment science and engineering and another goal is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working all around the world. The conference will be held every year to make it an ideal platform for people to share views and experiences in energy equipment science and engineering and related areas. This second volume of the two-volume set of proceedings covers the field of Structural and Materials Sciences, and Computer Simulation & Computer and Electrical Engineering.
