Research on the Mechanism of Improving Cannon Gun Barrel Life by Electrical Explosion Spraying Technology
ABSTRACT
Electrical explosion directional spraying as a new kind of thermal spraying technology has a unique advantage compared with the traditional hot spraying technology. It is very significant to study the mechanism of using the technology to improve anti-erosion in artillery barrel life. In this paper, appropriate improvement is made in the existing electric explosion spraying equipment. Pneumatic clamping way is used to improve the efficiency of spraying. The environmental protective dust removal system is made in order to reduce the harm of toxic smoke. Wire electrical explosion spraying principle and the present research status is also studied in this paper. 65 Mn, 0Cr18Ni9Ti, 2Cr13 coating is prepared by improved electric explosion spraying equipment. Coating microstructure was observed with optical microscope and scanning electron microscopy (SEM). The microstructure and hardness are analyzed. It is show that the coating organization is refined than the original microstructure, and coating/substrate interface combined well. There is obvious element diffusion phenomenon, and micro hardness of coating is significantly enhanced than the original hardness.
Take 0Cr18Ni9Ti coating for example, technological parameters of spraying process are analyzed, the thickness and porosity in different spraying conditions are compared by kinds of methods. It is showed that: with the increase of spraying voltage, coating porosity decreases and coating thickness increases, but the increase amplitude decrease; Coating thickness decreases and coating porosity increases,with the increase of the spraying distance; Coating thickness increases and coating porosity decreases with the increase of spraying times.
Take FeCrBSi coating for example, using numerical analysis method to analysis stress changes in the process of spray particle impacting the steel plate and deposition process of spray particle. The influence of coating thickness, internal stress of substrate and coating temperature on the coating, substrate temperature and cooling rate are discussed by means of the finite element method. Calculations show that shock wave of electrical explosion spraying process produced in different spraying distance and times, the internal stress of steel plate substrate changes little,almost without any damage to substrate. When coating thickness is unchanged, the higher coating initial temperature the greater influence is happened on substrate temperature of similar depth inner, temperature alteration ratio. In different depths of substrate, the higher coating initial temperature the greater influence on temperature and temperature alteration ratio of different depth inner substrate, the greatest influence occur at near junction surface of substrate and coating. In case of coating with same initial temperature the thinner coating thickness, the greater influence on temperature and temperature alteration ratio of different depth inner of substrate. In different depths of substrate, the thinner coating thickness the greater influence on temperature and temperature alteration ratio of different depth and direction inner of substrate, the greatest influence occur at near junction surface of substrate and coating.
Some performance contrast test are made between coating prepared by electrical explosion spraying technology and chromium coating of existing artillery barrel tube surface re-ablation after analysis on the characteristics of artillery barrel tube surface modification coatings.
Coating prepared by electrical explosion directional spraying is significantly better than chrome coating in anti-erosion when it is used in artillery chamber. The mechanism research results of improve artillery barrel life by electrical explosion spraying technology are got.
Key words: Electrical explosion spraying, Artillery barrel, Re-ablation
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