Investigation of material removal in inner-jet electrochemical grinding of GH4169 alloy

Hansong Li,Shuxing Fu,Qingliang Zhang,Ningsong Qu,Shen Niu

doi:10.1038/s41598-017-03770-1

Hansong Li, Shuxing Fu + Show 3 more

Open Access

https://doi.org/10.1038/s41598-017-03770-1

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Abstract

Electrochemical grinding (ECG) is a low-cost and highly efficient process for application to difficult-to-machine materials. In this process, the electrolyte supply mode directly affects machining stability and efficiency. This paper proposes a flow channel structure for an abrasive tool to be used for inner-jet ECG of GH4169 alloy. The tool is based on a dead-end tube with electrolyte outlet holes located in the sidewall. The diameter and number of outlet holes are determined through numerical simulation with the aim of achieving uniform electrolyte flow in the inter-electrode gap. Experiments show that the maximum feed rate and material removal rate are both improved by increasing the diamond grain size, applied voltage, electrolyte temperature and pressure. For a machining depth of 3 mm in a single pass, a feed rate of 2.4 mm min−1 is achieved experimentally. At this feed rate and machining depth, a sample is produced along a feed path under computer numerical control, with the feed direction changing four times. Inner-jet ECG with the proposed abrasive tool shows good efficiency and flexibility for processing hard-to-cut metals with a large removal depth.

Highlights

GH4169 (Ni–Fe–Cr) alloy, with its excellent fatigue resistance, high-temperature strength, and good resistance to corrosion and radiation damage, is widely used in a number of important industries, including aerospace, navigation and petroleum[1,2,3,4]
Electrochemical grinding (ECG) is a non-conventional hybrid process based on a combination of electrochemical machining (ECM) and mechanical grinding (MG)[16], with the electrochemical and abrasive actions contributing about 90% and 10%, respectively, of the total material removal[17, 18]
Each test started with a low feed rate, which was gradually increased by the motion control program, until a short-circuit current appeared in the current detection unit

Summary

Introduction

GH4169 (Ni–Fe–Cr) alloy, with its excellent fatigue resistance, high-temperature strength, and good resistance to corrosion and radiation damage, is widely used in a number of important industries, including aerospace, navigation and petroleum[1,2,3,4]. When traditional cutting processes are used, it is impossible to avoid problems such as severe tool wear, high work hardening and low material-removal rate (MRR), all of which lead to unacceptably high manufacturing costs[7]. As with other difficult-to-cut materials, attention has increasingly been focused on the use of non-conventional processes to machine GH4169 alloy at low cost and with high efficiency. Hascalık and Caydas[23] used ECG with a cutting depth of 0.05 mm and a feed rate of 24 mm min−1 to remove the damaged surface layers of Ti6Al4V alloy machined by EDM. Curtis et al.[24] investigated a method for machining both sides of a V-shaped slot in a nickel-based superalloy by using a mounted grinding point with fir-tree geometry, with a depth of cut and feed rate of 0.5 mm and 10 mm min−1, respectively. Qu et al.[25] used a spherical abrasive tool with rod-like geometry to machine Inconel 718, with a feed rate of 6.6 mm min−1 and a machining depth of 0.5 mm

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