Laser cladding of stainless-steel ball valves by a high-power diode laser source with a rectangular beam spot.

• The 2045 W laser is used for laser cladding. • This Gaussian light into a rectangular beam conversion facilitates high speed and efficient cladding. • The ball valve is crack-free and its surface hardness has been increased by 2.7 times. In this paper, the laser cladding of Ni60 + WC powder on the stainless-steel ball valves is investigated to improve the corrosion resistance and the wear resistance of industrial ball valves. A 2-kW high-power diode laser source based on beam multiplexing is used as the processing source to clad the ball valves. To make this diode laser source more reliable for laser cladding, a homogenizing optical system is designed and optimized to transform a circular beam spot output from the optical fiber to a rectangular spot with a flat-top distribution. Employing this diode laser source, the laser cladding of the stainless-steel ball valve is successfully achieved by use of the pre-set powder feeding. The hardness testing experiments are then performed on the ball valves of different diameters, followed by the evaluation of the thickness and hardness of the cladding coating. It is experimentally demonstrated that the microhardness of the ball valves is improved by 2.7 times and the cladding layer has no cracks, which proves the superior performance of the stainless-steel ball valves by use of the proposed method. [ABSTRACT FROM AUTHOR]