Gas–metal reaction products in the erosion of chromium-plated gun bores

Côté, Paul J.; Rickard, C. E.

doi:10.1016/s0043-1648(00)00311-2

Cited by 83 publications

(32 citation statements)

References 5 publications

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“…Historically, carburization has been important to the steel‐making industry for adjusting steel properties because the carbon content controls hardness and erosion resistances. In the present study, carburization is of interest because of its role in gun barrel erosion 2–5. Generally, gun barrel erosion mechanisms are categorized as chemical, thermal, and mechanical, which are all intimately coupled.…”

Section: Introductionmentioning

confidence: 99%

Iron carburization in CO‐H₂‐He gases, Part I: Experiment

Wang

Yetter

2009

Int J of Chemical Kinetics

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Carburization of iron was studied at atmospheric pressure over the temperature range 850 • C to 1150 • C in gaseous mixtures of CO, H 2 , and He. The resistance relaxation method was applied to measure the carburization rates. Experimental results show that for carburization in CO-He mixtures, the carburization rate increased proportionally with CO partial pressure with a reaction order of unity. The overall rate also increased with temperature up to approximately 960 • C and subsequently decreased with further increases in temperature. For carburization in CO-H 2 -He mixtures, the carburization rate increased with both the CO and H 2 partial pressures under most conditions and was considerably faster than the rate in mixtures without hydrogen. Up to approximately 960 • C, the rate was nearly independent of temperature with H 2 present, but decreased with a further increase in temperature. The decrease in reaction rate for mixtures with and without H 2 at 960 • C coincides closely with the change in phase of iron from α to γ . Experiments at 925 • C with constant P H 2 and P CO indicate that CO dissociation on the iron surface is faster than oxygen removal from the surface except at high ratios of P H 2 /P CO , and therefore oxygen removal was generally the rate-limiting step. The rate of oxygen removal from the surface by H 2 was found to be of the same order as that by CO. At high hydrogen levels, the rate of oxygen removal exceeds dissociative absorption of CO and the latter becomes rate controlling. The present results are used to establish a numerical model for the carburization of iron, which is described in a companion paper. C

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Section: Introductionmentioning

confidence: 99%

Iron carburization in CO‐H₂‐He gases, Part I: Experiment

Wang

Yetter

2009

Int J of Chemical Kinetics

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“…[1][2][3][4][5] Field observations as well as laboratory test results indicate that the typical failure mode of such coating-substrate systems often is a two stage process:…”

Section: Introductionmentioning

confidence: 99%

Measurement of fracture toughness and interfacial shear strength of hard and brittle Cr coating on ductile steel substrate

Yang

Zhang

Chen

et al. 2008

Surface Engineering

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The fracture toughness and interfacial adhesion properties of a coating on its substrate are considered to be crucial intrinsic parameters determining performance and reliability of coatingsubstrate system. In this work, the fracture toughness and interfacial shear strength of a hard and brittle Cr coating on a normal medium carbon steel substrate were investigated by means of a tensile test. The normal medium carbon steel substrate electroplated with a hard and brittle Cr coating was quasi-statically stretched to induce an array of parallel cracks in the coating. An optical microscope was used to observe the cracking of the coating and the interfacial decohesion between the coating and the substrate during the loading. It was found that the cracking of the coating initiated at critical strain, and then the number of the cracks of the coating per unit axial distance increased with the increase in the tensile strain. At another critical strain, the number of the cracks of the coating became saturated, i.e. the number of cracks per unit axial distance became a constant after this critical strain. Based on the experiment result, the fracture toughness of the brittle coating can be determined using a mechanical model. Interestingly, even when the whole specimen fractured completely under an extreme strain of the substrate, the interfacial decohesion or buckling of the coating on its substrate was completely absent. The test result is different from that appeared in the literature though the identical test method and the brittle coating/ductile metal substrate system are taken. It was found that this difference can be attributed to an important mechanism that the Cr coating on the steel substrate has a good adhesion, and the ultimate interfacial shear strength between the Cr coating and the steel substrate has exceeded the maximum shear flow strength level of the steel substrate. This result also indicates that the maximum shear flow strength level of the ductile steel substrate can be only taken as a lower bound estimate on the ultimate shear strength of the interface. This estimation of the ultimate interfacial shear strength is consistent with the theoretical analysis and prediction presented in the literature.

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“…It is well known that there exist lots of embedded microcracks within the HC Cr deposits. With exposure to high temperatures and mechanical wear from projectile passage during firing, the microcracks extend, and the surface microcracks, in particular, propagate through the chromium to the steel substrate, so that the original chromium plating becomes, in effect, an assembly of individual, isolated islands [17]. The chromium spalling process proceeds from this configuration by progressive removal of the individual isolated chromium islands through metal failure at or near the chromium-steel interface [17].…”

Section: Discussionmentioning

confidence: 99%

“…With exposure to high temperatures and mechanical wear from projectile passage during firing, the microcracks extend, and the surface microcracks, in particular, propagate through the chromium to the steel substrate, so that the original chromium plating becomes, in effect, an assembly of individual, isolated islands [17]. The chromium spalling process proceeds from this configuration by progressive removal of the individual isolated chromium islands through metal failure at or near the chromium-steel interface [17]. Therefore, one key measure to enhance the service life of chromium electrodeposits applied for gun barrels is to control segregation of chromium coatings and improve the damage resistance of individual isolated islands.…”

Section: Discussionmentioning

confidence: 99%

“…The repeated cycling of high pressure and high temperature together with chemical interaction with hot propellant gases causes severe damage to chromium-plated gun barrels [4][5][6][7][8][9][10][11][12][13][14][15][16]. Moreover, the erosion damage of chromium-plated gun barrels is accelerated by chromium spallation, which allows hot gas attack and/or melting of the unprotected substrate steel [17]. With increasing demands for range, rate of fire, and muzzle velocity, increased wear and erosion problems in chromium-plated gun tubes have been caused, and the single traditional chromium plating cannot meet the practical requests.…”

Section: Introductionmentioning

confidence: 99%

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Degradation failure features of chromium-plated gun barrels with a laser-discrete-quenched substrate

Chen

Zhang

et al. 2007

Surface and Coatings Technology

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The effect of substrate laser-discrete quenching on the degradation failure of chromium-plated gun barrels was metallurgically investigated. The results show that substrate laser-discrete quenching changes the failure patterns of chromium coatings during firing, and some periodic through-thickness cracks in the fired chromium coatings are justly located at original substrate zones between two adjacent laser-quenched tracks. Moreover, chromium coatings and the laser-quenched zones on the substrate are simultaneously degraded in microstructure and property during firing. Furthermore, the periodic structure of the laser-discrete-quenched steel (LDQS) substrate near the breech remains after firing, and the hardness of the fired laser-quenched zones is still higher than that of original substrates. The specific failure features were utilized to illustrate the mechanism of the extended service life of chromium-plated gun barrels with the LDQS substrate.

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Gas–metal reaction products in the erosion of chromium-plated gun bores

Cited by 83 publications

References 5 publications

Iron carburization in CO‐H₂‐He gases, Part I: Experiment

Iron carburization in CO‐H₂‐He gases, Part I: Experiment

Measurement of fracture toughness and interfacial shear strength of hard and brittle Cr coating on ductile steel substrate

Degradation failure features of chromium-plated gun barrels with a laser-discrete-quenched substrate

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Gas–metal reaction products in the erosion of chromium-plated gun bores

Cited by 83 publications

References 5 publications

Iron carburization in CO‐H2‐He gases, Part I: Experiment

Iron carburization in CO‐H2‐He gases, Part I: Experiment

Measurement of fracture toughness and interfacial shear strength of hard and brittle Cr coating on ductile steel substrate

Degradation failure features of chromium-plated gun barrels with a laser-discrete-quenched substrate

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Iron carburization in CO‐H₂‐He gases, Part I: Experiment

Iron carburization in CO‐H₂‐He gases, Part I: Experiment