On the Assessment of Surface Quality and Productivity Aspects in Precision Hard Turning of AISI 4340 Steel Alloy: Relative Performance of Wiper vs. Conventional Inserts.

Adel T Abbas,Monis Luqman,Magdy M El Rayes,Ahmed Elkaseer,Hussien Hegab,Noha Naeim

doi:10.3390/ma13092036

Abstract

This article reports an experimental assessment of surface quality generated in the precision turning of AISI 4340 steel alloy using conventional round and wiper nose inserts for different cutting conditions. A three-factor (each at 4 levels) full factorial design of experiment was followed for feed rate, cutting speed, and depth of cut, with resulting machined surface quality characterized by resulting average roughness (Ra). The results show that, for the provided range of cutting conditions, lower surface roughness values were obtained using wiper inserts compared with conventional inserts, indicating a superior performance. When including the type of insert as a qualitative factor, ANOVA revealed that the type of insert was most important in determining surface roughness and material removal rate, with feed rate as the second most significant, followed by the interaction of feed rate and type of insert. It was found that using wiper inserts allowed simultaneous increases in feed rate, cutting speed, and depth of cut, while providing better surface quality of lower Ra, compared to the global minimum value that could be achieved using the conventional insert. These findings show that wiper inserts produce better surface quality and a material removal rate up to ten times higher than that obtained with conventional inserts. This clearly indicates the tremendous advantages of high surface quality and productivity that wiper inserts can offer when compared with the conventional round nose type in precision hard turning of AISI 4340 alloy steel.

Highlights

Precision hard turning concerns the turning of material with superior mechanical properties [1], high levels of strength [2] and hardness [3] such as alloy steels [4] and nickel-based super alloys [5,6], materials with high strength/weight ratio [7] and wear resistance [8] such as titanium alloys [9]
Both graphs show a comparison between the performances of wiper vs. conventional inserts in term of resultant surface roughness (Ra and Rz in μm) of machined AISI 4340 specimens under the whole range of cutting parameters
This paper has presented the results of an experimental-based investigation into the effect of cutting conditions on generated surface roughness when hard turning AISI 4340 alloy steel using wiper and conventional round nose carbide inserts

Summary

Introduction

Precision hard turning concerns the turning of material with superior mechanical properties [1], high levels of strength [2] and hardness [3] such as alloy steels [4] and nickel-based super alloys [5,6], materials with high strength/weight ratio [7] and wear resistance [8] such as titanium alloys [9] These materials fulfil a wide range of industrial requirements [10], they are Materials 2020, 13, 2036; doi:10.3390/ma13092036 www.mdpi.com/journal/materials. A cost-effective alternative for materials with high hardness was shown to be precision hard turning, which has the added advantage of a relatively high throughput with a reduction in processing time up to 60%, when compared with grinding [13] This is due mainly to its ability to precisely machine components to produce complex geometries with tight tolerances and higher surface quality and material removal rate (MRR) [14]. This has led to an increased adoption of precision hard turning by industry for different applications, including automotive, marine, power engine, aerospace, and military components

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