Characterisation of friction and heat partition coefficients at the tool-work material interface in cutting

Rech, J.; Arrazola, P.J.; Claudin, C.; Courbon, C.; Pušavec, Franci; Kopač, Janez

doi:10.1016/j.cirp.2013.03.099

Cited by 170 publications

(96 citation statements)

References 15 publications

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“…from 0.2 to about 0.6). Increasing the cutting speed these differences are getting smaller and the curves approach a value of 0.2 in dry conditions, which corresponds to a semi-solid frictional regime as assumed by Neugebauer et al [6] and Rech et al [7].…”

Section: Resultsmentioning

confidence: 93%

The Behaviour of Graphitized Steels in Machining Processes

Roelofs

Renaudot

Smolenicki

et al. 2016

MSF

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Abstract. Graphitized steels are claimed to perform excellent in machining processes. They therefore can be considered as environmental friendly alternatives to widely used Pb-alloyed steels. Due to liquid metal embrittlement and in-situ lubrication Pb improves machinability in a narrow tool-chip interface temperature window corresponding to low machining speeds. Although graphite inclusions are also supposed to generate in-situ lubrication, the mechanism and the corresponding optimum working zone is not very clear. The present work applies a new test methodology (including in-situ tribology, analysis of material flow and chip formation, optimum working zone analysis) to investigate the effect of graphite inclusions in turning and drilling operations. Pballoyed low carbon free-cutting steel and Pb-alloyed case hardening steel were used as reference steels. IntroductionUsing free cutting steels in mass production machining performance is the most important property. It is the main factor influencing part production costs. Widely spread low carbon free cutting steels like 11SMn30 exhibit low hardness resulting in low machining forces. Addition of sulphur leads to the formation of manganese sulphides, which protect the machining tool by in-situ layer formation and reduces friction forces in the chip-tool interface. As a consequence high productivity and long tool lifetimes are reached. However the ferrite matrix of such steels is soft and tends to stick on the tool surface if cutting speeds are low. This so called built-up edge formation (BUE) can be a severe problem producing small parts or in machining operations with partially low speeds like cutting-off or drilling. BUE formation can be efficiently suppressed by adding lead to the steel. Liquid lead then acts as lubricant in the chip-tool interface. Due to its low melting point this effect already occurs at low machining speeds. At higher speeds this benefit disappears (which might be caused by a change in viscosity). As a rule of thumb considering all kind of machining conditions productivity of leaded steel 11SMnPb30 is estimated to be 20% higher comparing to non-leaded steel 11SMn30. This explains the popularity if this steel which is consumed in large quantities in machining workshops all over the world.

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Section: Resultsmentioning

confidence: 93%

The Behaviour of Graphitized Steels in Machining Processes

Roelofs

Renaudot

Smolenicki

et al. 2016

MSF

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“…The heat partition coefficient for the tool (l) was selected as 0.85 and 0.60 corresponding to the two cutting speeds as reported in [18].…”

Section: Thermal Modelingmentioning

confidence: 99%

Thermal analysis in Ti-6Al-4V drilling

et al. 2017

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“…Concerning the tribological characteristics of the tool-chip and tool-workpiece interfaces, Zorev's model was used [9]. The value of the friction coefficient was determined from tribological tests described in [10]. These tests enabled the determination of the apparent friction coefficient (m app ), which includes both contributions of interfacial (local) adhesive phenomena (m adh ) and macroscopic plastic deformation (m plast ).…”

Section: Numerical Models and Parametersmentioning

confidence: 99%