Application of Hall effect for assessing grinding thermal damage

https://doi.org/10.1016/j.jmatprotec.2019.02.019Get rights and content

Abstract

The limitations of the usual techniques applied for gear grinding burn detection are extended by the increasing demands on quality control within industrial feasibility. Although widely used, nital etching technique has a subjective character. Alternative techniques such as magnetic Barkhausen noise and X-ray diffractometry also present drawbacks such as variability of output based on external energy input that depends on parameter settings, high cost and destruction of tests parts. Due to this technical gap, an alternative method is suggested, where the remanent induction of a workpiece is measured by means of a Hall probe. The objective of this concept is to reduce external inputs on the workpiece, measuring its natural signal and correlating it to the material property induced by the damage. In this study, three different degrees of damage were investigated with the Hall method, covering damages with phase transformation as well as with modifications on the residual stress state. According to the results obtained, an alteration in the remanent induction which is directly correlated to the burn degree, was detected. The micro-magnetic theory establishes a correlation between the remanent magnetic induction and material hardness as well as residual stress state. The signal alteration detected by the Hall method is in accordance with the micro-magnetic theory for all three degrees of burn analyzed.

Introduction

According to Gorgels et al. (2006), the demands for higher surface quality by the advancing technical and precision aspects of modern gears lead to the application of finishing processes. Grinding is a process commonly applied due to unique advantages, such as high dimensional accuracy and improvement of surface quality, as established by Shah (2011). However, if the temperature reaches critical high values during the process the gear surface properties deteriorates, leading to the thermal damage known as grinding burn (Karpuschewski et al., 2011). According to Rowe (2014), grinding burn directly influences the surface integrity, introducing tensile residual stresses, phase transformation and micro-cracks. These alterations are highly undesired as they lead to reduction of fatigue life and, eventually, to tooth breakage during operation. In order to avoid damaged components, a robust and efficient measurement technique is required.

The main objective of this study is to investigate an alternative method for detecting different degrees of grinding burn by means of the Hall effect, without application of an external magnetic field. The alternative method proposed is hence referred to as Hall method. The correlation between the remanent induction and material properties was already addressed in researches before. Roskosz and Bieniek (2012) investigated the correlation between remanent induction and different states of residual stresses.In his work, Chongchong et al. (2016) investigated the correlation between the remanent induction and crack initiation. Both researchers introduced an initial mathematical correlation between the investigated phenomena. The objective of this research, however, is to further contribute to the application of this theory, with the development of a method based on the remanent signal magnitude.

For the development of the method proposed in this work, the understanding of two concepts is essential: material properties induced by the thermal damage and material magnetic behavior. Both concepts will be addressed in the following topics, as well as a description of the currently detection methods available.

Section snippets

Background

This chapter is divided into two subtopics: “Established methods for grinding burn detection” and “Fundamentals of a method based on Hall effect”. In the first subtopic, a review of the state-of-the-art regarding the methods available for the grinding burn detection is presented. Due to the focus of the research, the review concentrates specially on the magnetic methods, introducing their advantages as well as challenges. Subsequently, the second topic describes the magnetic concept applied in

Materials and methods

In order to reach the objective established, a first prototype of a measurement device was built, according to the measurements basic requirements, bottom left Fig. 2. First, the Hall probe must be able to access the entire workpiece surface, in order to scan it. Second, the Hall probe must be parallel to the analyzed surface. In the measurement device, the probe is fixed in a clamping support, assuring its parallel position to the workpiece surface during measurement. The support is attached

Results and discussions

This chapter is divided into two subtopics, presenting the results obtained for the two cases investigated in this research: Case 1 – Thermal damages without phase transformation and Case 2 – Thermal damages with phase transformation.

Firstly, results regarding the repeatabilitiy of the method are shown in Fig. 4, in a boxplot graphic.

The MBN, for example, is a very sensitive technique, which hinders the repeatability. The degree of repeatability of the Barkhausen signal varies according to the

Conclusions

The presented study investigated an alternative method for thermal damage detection, by means of the Hall effect. The characterization of each thermal damage surface degree was performed by conventional techniques such as nital etching and surface indentation. The results showed a consistent behavior with the literature for each degree. The presence of a thermally affected region in the surface induced an alteration in the magnetic signal, detected by the Hall method for the three thermal

Declarations of interest

None.

Acknowledgments

The authors would like to thank the National Council for Scientific and Technological Development (CNPq) and the WZL Gear Research Circle for the financial support. The authors are also grateful to the Instituto SENAI Santos Dumont, the Fraunhofer Institute for Production Technology and to the Companhia Industrial de Peças (CIP), for disposing their facilities for the experimental developments.

References (24)

  • B.L. Bramfitt et al.

    Metallographer’s Guide: Practice and Procedures for Irons and steels

    (2002)
  • N.P. Gaunkar

    Magnetic Hysteresis and Barkhausen Noise Emission Analysis of Magnetic Materials and Composites

    (2014)
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