Investigation on Surface Integrity in Milling of Inconel X750: A Comprehensive analysis of Cutting Edges and Machining Parameters

• Published in: International journal of refractory metals & hard materials Vol. 121; p. 106662
• Main Authors: Chauhan, Shailendra, Trehan, Rajeev, Singh, Ravi Pratap, Sharma, Vishal S.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-06-2024
• Subjects: Inconel X-750; Residual stresses; RSM; Sub-surface microstructure; Surface roughness; Surface topography; Sub-surface microstructure; Surface roughness; Inconel X-750; Residual stresses; Surface topography; RSM
• ISSN: 0263-4368; 2213-3917
• DOI: 10.1016/j.ijrmhm.2024.106662

For over a century, machining has been a crucial manufacturing method, with milling standing out as a versatile and effective process for various engineering materials. Ni-based superalloys, renowned for their exceptional properties, present challenges in machining, causing excessive tool wear and surface quality issues. Techniques such as heat treatments, environmental adjustments, and tool geometry alterations are employed to mitigate tool wear and affect surface integrity, crucial for determining the quality of machined work materials, especially in high-strength superalloys where shear deformation induces grain misorientation. In this research article, an experimental study was carried out to find the impact of the different cutting edges on surface integrity while milling Inconel X750. Response Surface Methodology was employed using a central composite rotatable design of experiments to investigate the surface roughness of the machined sample under various cutting conditions. A thorough analysis was undertaken to explore the surface integrity of Inconel X750, involving variations in milling machining parameters (i.e., low, mid, and high) and the utilization of diverse cutting tool inserts. The investigation centred on analysing the sub-surface microstructure, texture, and residual stresses of the machined surface, aiming to achieve a comprehensive understanding of the material's surface characteristics. The double-coated cutting tool T2, with a diameter of 0.8 mm, exhibited superior performance in surface quality and grain distribution, particularly at low cutting parameters (feed rate: 0.15 mm/rev, cutting speed: 35 mm/min, depth of cut: 0.1 mm), showing fine equiaxed and lognormal grain distribution alongside low residual stresses (−36.8 MPa compressive, maximum shear residual stresses: 7.2 MPa) and a surface roughness of 0.17 μm.
•In tIn the present work, an attempt has been made to Investigate the Surface Integrity in Milling of Inconel X750, utilizing two types of inserts with cutting-edge radii of 0.8 and 0.4 mm. The proposed method centers on surface integrity attributes i.e., Surface roughness, Sub-surface Microstructure, Sub-surface Texture and Surface Residual Stresses after milling Ni-based superalloy with two different inserts, which further supports overcoming the associated challenges in the available literature. The major highlights of the attempted work are as below;•A thorough examination of the existing literature indicates a notable gap in past investigations within the subject domain. Specifically, there is a scarcity of research focusing on critical post-machining surface integrity aspects, such as grain misorientation intensity, grain elongation, and residual stresses. These aspects, of paramount significance, play a pivotal role in the utilization of advanced materials in typical engineering applications.•This research article presents the outcomes of a comparative experimental investigation of the surface characterization as well as an analysis of the subsurface microstructural modifications and residual stresses in Inconel X750 that was milled utilizing various cutting tool inserts. Response Surface Methodology, employing a central composite rotatable design of experiments, was utilized to investigate the surface roughness of machined samples under various cutting conditions.•A comprehensive analysis explored the surface integrity of Inconel X750, considering variations in milling machining parameters (i.e., low, mid, and high) derived from the experimental design, and the use of diverse cutting tool inserts.•The investigation focused on the sub-surface microstructure, texture, and residual stresses of the machined surface, striving for a comprehensive understanding of the material's surface characteristics, with the cutting tool (T2) (0.8mm, double coated) exhibiting superior performance in terms of surface quality and optimal grain distribution. Further at low cutting parameters the grains were fine equiaxed and lognormal distributed, along with low residuals stresses and low surface roughness.