ASTM B443 N06625 Nickel Alloy Plate Machining Recommendations

ASTM B443 N06625, or Inconel 625, is a nickel-based alloy plate known for its corrosion resistance and high strength, but its rapid work-hardening properties pose challenges during machining. To achieve optimal results, specific techniques and tools are recommended to ensure precision and tool longevity.

Tool Selection: Use high-speed steel (HSS) or carbide tools with sharp cutting edges to minimize work hardening. Coated carbide tools, such as those with TiAlN or AlTiN coatings, enhance wear resistance. Ensure tools are rigid and well-maintained to prevent chatter and ensure clean cuts.

Cutting Parameters: Employ low cutting speeds (15–30 m/min for turning, 10–20 m/min for milling) to reduce heat buildup. Use moderate feed rates (0.05–0.15 mm/rev for turning) to avoid excessive tool wear. Maintain consistent cutting depths to prevent surface hardening, typically 0.5–2 mm for roughing and 0.1–0.5 mm for finishing.

Coolant and Lubrication: Apply copious amounts of water-based or oil-based coolant to dissipate heat and reduce tool wear. Flood cooling is preferred to maintain consistent temperatures during machining.

Machine Rigidity: Use rigid, high-power machine tools to counteract Inconel 625’s toughness. Secure workpieces firmly to minimize vibration. For complex shapes, consider CNC machining for precision.

Welding and Forming: Inconel 625 is weldable using GTAW or GMAW without preheating, but post-weld heat treatment may be needed for stress relief. For forming, cold working is feasible, but annealing may be required to restore ductility.

Safety and Inspection: Wear protective gear due to nickel dust hazards. Verify machined parts with non-destructive testing to ensure compliance with ASTM B443 standards. These practices ensure efficient machining of Inconel 625 plates.