Analysis of the surface geometric structure after abrasive water jet cutting of a X39Cr13 alloy

Abrasive water jet (AWJ) cutting is an unconventional machining technique widely used to process various materials, including metals, plastics, ceramics, and stone. The key advantage of the AWJ process is its low cutting temperature, which prevents thermal defects in the material’s surface layer. However, the abrasive water jet dissipates within the material, leading to the formation of irregular surface geometry. This study presents an experimental investigation of AWJ cutting of X39Cr13 stainless steel to determine the relationships between cutting parameters, such as cutting speed (ranging from 20 to 60 mm/min), cutting depth (up to 10 mm), and abrasive flow rate (ranging from 75 to 165 g/min) and surface roughness (Ra, Rt) and waviness (Wa, Wt) parameters. The results indicate that the surface of X39Cr13 stainless steel after AWJ cutting is characterised by six distinct zones. Initial Cutting Region with defects, Extra Smooth Cutting Region, Smooth Cutting Region, Rough Cutting Region with visible grooves, Output Cutting Region with defects and Edge Chamfer. In addition, the feed rate has a strong influence on the curvature of the cutting jet and the spacing between the cutting traces. The cutting depth was found to be the most influential parameter that affects surface roughness and waviness, contributing approximately 40–50% in the models obtained. The second most significant factor that affects surface quality is the feed rate, which has the greatest effect on the waviness parameters Wa and Wt. Within the cutting depth range up to 10 mm, the Ra parameter was observed to vary from 1.5 to 14.5 µm, while the Wa parameter ranged from 0.4 to 42 µm.