Research on CNC Turning Process of 3Cr13 Stainless Steel

Although rough machining, semi-finishing, and finishing of stainless steel on conventional lathes are relatively straightforward, achieving high-quality results on high-productivity CNC lathes presents significant challenges. Issues such as excessive cutting forces, high temperatures, severe tool wear, poor surface finish, and low productivity often arise when working with stainless steel. These problems are even more pronounced when machining 3Cr13 stainless steel, a material known for its high strength, good plasticity, and tendency to work-harden during cutting. In this study, the author conducted extensive trials and adjustments in various aspects, including tool material selection, tool geometry, cutting parameters, lubrication, and blank condition, to achieve successful machining outcomes. During initial trials, turning 3Cr13 using methods similar to those for ordinary carbon steels like 40 or 45 steel resulted in severe tool wear, low productivity, and poor surface quality. This is due to the higher mechanical properties of 3Cr13—such as greater tensile strength, elongation, and impact resistance—as well as its tendency to work-harden, leading to increased cutting resistance and heat generation. The material’s high adhesion also causes built-up edge formation, which affects dimensional accuracy and surface roughness. Additionally, chip curling and breaking become difficult, further degrading the surface finish. Because of these challenges, it is not feasible to directly apply conventional lathe techniques to CNC lathes. CNC machines typically have fewer tools, so each pass must be optimized to ensure both dimensional accuracy and surface quality while maximizing productivity. To address these issues, the author implemented several key strategies. First, the hardness of the material was adjusted through heat treatment. Annealed 3Cr13 showed poor machinability due to its soft, non-uniform microstructure and high adhesion. However, after quenching and tempering to reach a hardness of HRC 25–30, the material became more manageable, allowing for better surface finish and tool life. Next, the choice of tool material was crucial. Comparative tests showed that TiC-TiCN-TiN coated carbide tools performed best, offering high durability, good surface quality, and improved productivity. When such tools were unavailable, YW2 cemented carbide proved to be a suitable alternative. Tool geometry and structure were also carefully considered. A larger rake angle (10°–20°) was used to reduce cutting resistance, while the relief angle (5°–8°) was kept moderate to prevent excessive friction and tool wear. Negative rake angles helped protect the cutting edge and improve blade strength. For chip control, an external oblique circular arc chipbreaker was used to enhance chip breaking and evacuation. Cutting parameters were optimized based on material properties and tool performance. Lower cutting speeds (60–80 m/min) and moderate feed rates (0.1–0.2 mm/r) were found to be most effective in reducing tool wear and improving surface finish. Finally, a custom coolant mixture of 1:9 four-grid carbon oil was selected for its excellent cooling, lubrication, and penetration properties, significantly improving the machining process. After implementing these measures, the machining of 3Cr13 stainless steel became stable and efficient. Tool sharpening frequency dropped by two-thirds, and overall productivity increased significantly. The final part quality met all design requirements, proving that with proper techniques, even challenging materials like 3Cr13 can be successfully machined on CNC lathes.

Carbon Fiber Pickleball Paddle

Carbon Fiber Pickleball Paddle,Carbon Pickleball Paddle,Pickleball Paddle Carbon Fiber,Carbon Fiber Paddle Pickleball

Nantong Zhongyi Electronic Technology Co., Ltd. , https://www.apl-pickleball.com