Laser surface modification of hard chrome-plated gun barrels for performance enhancement

Hard chrome plating serves as an effective yet imperfect solution for addressing wear, corrosion and thermal and mechanical stability in gun barrels. Its microcracked structure and dependence on proper adhesion make it prone to failure in harsh or high-stress environments. Although hard chrome plating continues to be a main choice in military and duty firearms because of its cost-effectiveness and performance, this work introduces a laser surface modification technique aiming to modify the hard chrome plating by remelting the plating layer and making it mix with the steel substrate, to obtain alloyed surfaces that are free of cracks and form a metallurgical bond with the steel substrate. In a high-temperature erosion-wear test simulating the firing process, the modified surfaces demonstrated excellent wear performance. When compared with untreated plating, the laser-modified plating also demonstrated a significant improvement in its resistance to high-temperature erosion, as well as corrosion in 5% HCl solution. A semi-closed bomb test revealed that gun barrels with laser-treated inner walls maintained structural integrity, whereas untreated hard chrome plating suffered a complete failure. This work establishes a novel method for producing durable hard chrome plating to improve gun barrel protection.