Pre-Machining of Rolled Plates as an Element of Minimising the Post-Machining Deformations.

Magdalena Zawada-Michałowska,Paweł Pieśko,Józef Kuczmaszewski

doi:10.3390/ma13214777

Magdalena Zawada-Michałowska, Paweł Pieśko + Show 1 more

Open Access

https://doi.org/10.3390/ma13214777

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Journal: Materials	Publication Date: Oct 26, 2020
Citations: 8	License type: CC BY 4.0

Affiliation: Lublin University of Technology

Abstract

The paper presents the influence of the milling strategy, the relation between the cutting tool feed direction and the rolling direction, as well as the pre-machining consisting of the removal of the textured surface layer of rolled plates in the rolling process on the thin-walled elements deformations made of the EN AW-2024 T351 wrought aluminium alloy, after milling. The research used strategies such as: high-performance cutting (HPC), high-speed cutting (HSC) and conventional milling (CM), as well as their combinations. Another tested variable was the relation between the tool feed direction and the rolling direction. In addition, the tests were carried out in the following versions: leaving the textured surface layer created after plastic working and with its removal with technological parameters corresponding to HSC and CM. Based on the obtained results, it was found that the post-machining deformation of thin-walled elements can be minimised owing to the use of a selected milling strategy and its combination with pre-machining (or lack thereof). It was also observed that larger deformations were obtained for samples after milling in the direction perpendicular to the rolling direction.

Highlights

A major problem in cutting of the thin-walled elements is post-machining deformation that occur when the workpiece is removed from the clamping device
The analysis ofof the fromsamples samplesininwhich whichthe thetextured textured surface layer formed after rolling with the use of Relative deformations ε obtained after layer formed after rolling with the use of conventional milling (CM)
In order to compare the relative deformations ε in configurations with pre-machining with technological parameters corresponding to the high-speed cutting (HSC) and CM as well as without its use, the results technological parameters corresponding to the HSC and CM as well as without its use, the results presented in [46] were referenced

Summary

Introduction

A major problem in cutting of the thin-walled elements is post-machining deformation that occur when the workpiece is removed from the clamping device. As a result of external factors, including, among others, mechanical, thermal, structural, or a combination thereof, the material deforms elastically and plastically. The reversible changes disappear (elastic deformations), and the remaining irreversible changes (plastic deformations) cause the formation of residual stresses, counterbalancing each other within a specific area. This is mainly the result of an increase in the internal energy of the element leading to distortion of the crystal lattice. This brings about changes in material properties (e.g., reduction in corrosion resistance) and problems related to maintaining dimensional and shape accuracy. The residual stresses are caused by mutually correlated factors (e.g., thermal and structural stresses occur after the quenching), and their exact distinction is exceedingly difficult [4,7,8,9,10]

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