Detection of the Onset of Galling in Strip Reduction Testing Using Acoustic Emission

Moghadam, Marcel; Christiansen, Peter Leth; Bay, Niels

doi:10.1016/j.proeng.2017.04.011

Cited by 16 publications

(15 citation statements)

References 6 publications

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“…The main problems observed in warm and hot forming processes are that high friction and wear occur because of high adhesion between the workpiece material and tool surface, and surface-initiated fatigue. The occurrence and prevention of galling mechanism are investigated by using tribometers for metal forming at elevated temperatures [12,27,63]. The typically used pin-on-disc tribometer to characterize frictional contact in hot stamping do not reproduce appropriate contact conditions.…”

Section: Discussionmentioning

confidence: 99%

“…Strip Reduction Tests (SRTs) represent severe tribological conditions with low slipping length, high normal pressure, and surface expansion. Some types of SRTs are tests carried out with a reduction of the sheet thickness between flat [62] or cylindrical [38,63] counter-samples. One of the first experimental approaches for the simulation of the ironing process was developed by Fukui et al [64], who made direct measurements of friction force in metal-strip drawing where the strip was made to reduce between two stationary dies.…”

Section: Friction In Ironing In a Conical Diementioning

confidence: 99%

“…Recently, Moghadam et al [63] developed the method of detection of the onset of galling in strip reduction testing using acoustic emission. They investigated the same apparatus as Andreasen et al [68].…”

Section: Friction In Ironing In a Conical Diementioning

confidence: 99%

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Recent Developments and Trends in the Friction Testing for Conventional Sheet Metal Forming and Incremental Sheet Forming

Trzepieciński

Lemu

2019

Metals

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Friction is the main phenomenon that has a huge influence on the flow behavior of deformed material in sheet metal forming operations. Sheet metal forming methods are one of the most popular processes of obtaining finished products, especially in aerospace, automobile, and defense industries. Methods of sheet forming are carried out at different temperatures. So, it requires tribological tests that suitably represent the contact phenomena related to the temperature. The knowledge of the friction properties of the sheet is required for the proper design of the conditions of manufacturing processes and tools. This paper summarizes the methods used to describe friction conditions in conventional sheet metal forming and incremental sheet forming that have been developed over a period of time. The following databases have been searched: WebofKowledge, Scopus, Baztool, Bielefield Academic Search Engine, DOAJ Directory of Open Access Journals, eLibrary.ru, FreeFullPdf, GoogleScholar, INGENTA, Polish Scientific Journals Database, ScienceDirect, Springer, WorldCat, WorldWideScience. The English language is selected as the main source of review. However, in a limited scope, databases in Polish and Russian languages are also used. Many methods of friction testing for tribological studies are selected and presented. Some of the methods are observed to have a huge potential in characterizing frictional resistance. The application of these methods and main results have also been provided. Parameters affecting the frictional phenomena and the role of friction have also been explained. The main disadvantages and limitations of the methods of modeling the friction phenomena in specific areas of material to be formed have been discussed. The main findings are as follows—The tribological tests can be classified into direct and indirect measurement tests of the coefficient of friction (COF). In indirect methods of determination, the COF is determined based on measuring other physical quantities. The disadvantage of this type of methods is that they allow the determination of the average COF values, but they do not allow measuring and determining the real friction resistance. In metal forming operations, there exist high local pressures that intensify the effects of adhesion and plowing in the friction resistance. In such conditions, due to the plastic deformation of the material tested, the usage of the formula for the determination of the COF based on the Coulomb friction model is limited. The applicability of the Coulomb friction model to determine the COF is also very limited in the description of contact phenomena in hot SMF due to the high shear of adhesion in total contact resistance.

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Section: Discussionmentioning

confidence: 99%

Section: Friction In Ironing In a Conical Diementioning

confidence: 99%

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Recent Developments and Trends in the Friction Testing for Conventional Sheet Metal Forming and Incremental Sheet Forming

Trzepieciński

Lemu

2019

Metals

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“…(6) The onset of galling in strip reduction was investigated. (7) A technique for process monitoring in the deep drawing of a steel sheet was presented. (8) Smart metal forming with a digital process and IoT was reviewed.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Tool Fracture in Punching of Thick Steel Plate

Yamashita¹,

Murase²,

Nikawa³

2020

Sensors and Materials

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The sensing of acoustic emission (AE) is efficiently used for the detection of the crack initiation of brittle materials and defects in plastic forming and other manufacturing processes. We carried out circular hole punching tests using carbon steel S45C plates of 5 or 6 mm thickness. The objective was to capture the occurrence of cracks as a predictive phenomenon of punch fracture and their propagation during punching by using an AE sensor. The impulsive stress acting on the punch due to the sudden drop in punch force at the fracture of the plate was also measured using strain gages. This stress induced fracture at the stepped portion of the punch. The maximum tensile stress of the punch depended on the fillet radius at the stepped portion. A reciprocal punching test using both plates alternately was performed to evaluate the detection of crack initiation using an AE waveform. Features in the AE waveform due to crack initiation and the frictional behavior of the crack were captured.

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“…Detecting galling at an early stage is important to reduce the production of scrap products and minimize material consumption. The use of acoustic emission has been suggested as a way to monitor galling in industrial applications [4]. It was demonstrated using a strip reduction test and showed promising results also for minor levels of galling.…”

Section: Introductionmentioning

confidence: 99%

On the Role of Material Transfer in Friction Between Metals: Initial Phenomena and Effects of Roughness and Boundary Lubrication in Sliding Between Aluminium and Tool Steels

2018

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In the absence of a lubricant, the friction we measure in sliding contact between metals is typically high and quite erratic, with rapid fluctuations. If we filter out these rapid fluctuations, we can typically also notice slower trends, which can lead to quite dramatic friction changes. Unless careful studies are performed, the cause to this behaviour cannot be understood. How come a material couple cannot be characterised with a specific coefficient of friction? The present paper sets out to add understanding to this area, by conduction and analysing an experimental series involving sliding between a needle-like aluminium tip against tool steel flats. The load is high enough to cause substantial plastic deformation of the aluminium needle; its tip becomes formed by the contact against the tool steel. These small-scale, low sliding distance tests facilitate detailed studies of the initial stages of various friction trends, and the effects of initial surface roughness and shifts of this roughness caused by material transfer between the sliding surfaces. Specifically, the effects on the transfer and friction behaviour from presence or absence of a boundary lubricant film and atmospheric oxygen were studied. It was found that very smooth sliding surfaces can offer low-friction conditions for these metal types. However, the smooth sliding interface is very fragile. In all unlubricated cases tested, it very rapidly (in less than a few mm sliding) became ruined due to transfer, and the friction level correspondingly increased. The boundary lubricant could only offer low friction in cases where the flat steel surface was very smooth. The lubricant also facilitated smoothening of transferred aluminium. As long has been well known, boundary lubrication films typically do not totally hinder direct metallic contact in solid to solid contact. The present results strengthen this view and further suggests that in these direct contacts one of the major friction reducing effects of the lubricant is to efficiently limit transfer, which otherwise acts to make the sliding surface rough.

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Detection of the Onset of Galling in Strip Reduction Testing Using Acoustic Emission

Cited by 16 publications

References 6 publications

Recent Developments and Trends in the Friction Testing for Conventional Sheet Metal Forming and Incremental Sheet Forming

Recent Developments and Trends in the Friction Testing for Conventional Sheet Metal Forming and Incremental Sheet Forming

Prediction of Tool Fracture in Punching of Thick Steel Plate

On the Role of Material Transfer in Friction Between Metals: Initial Phenomena and Effects of Roughness and Boundary Lubrication in Sliding Between Aluminium and Tool Steels

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