INVESTIGATING THE IMPACT OF HIGH VELOCITY OXY-FUEL SPRAYING TECHNOLOGY PARAMETERS ON THE HARDNESS OF CARBIDES MATERIAL COATING FOR INTERNAL SURFACE OF PIPES

Tóm tắt

The hardness of high-speed oxyfuel thermal spray coatings is a major factor determining coating properties, especially when applying thick coatings for repair purposes. This study aims to optimize and determine the influence of HVOF (High velocity oxy-fuel) spraying parameters on the hardness of WC-12Co coatings applied to the internal surface of 20Cr steel pipes. The parameters investigated are spray distance (L), powder feed rate (P), and relative velocity of spray gun (V). The experimental parameters were determined by using a Taguchi L9 orthogonal design. The results showed that the optimal spraying parameters were L2 = 0.25 m, P1 = 20 g/min, and V3 = 0.2 m/s, resulting in a maximum coating hardness of 1308.6 HV. The effect of spraying parameters on hardness was observed to follow the order P (48.5%) > L (33.7%) > V (17.0%). An experimental function was developed to establish the relationships between hardness and spraying parameters, enabling the evaluation of the influence of the researched spraying parameters on hardness.