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The paper addresses the identification of constitutive parameters of thick, brittle layers on metal substrates. Application is to the iron oxide behaviour during hot rolling processes of steel, where oxide scale breaking and embedding is one of the major causes of surface defects. Contact management of a FEM software has been adapted in order to address the transitions corresponding to transverse...
This paper proposes a new concept of the ‘engineering surface’, which extends the conventional idea of a functional surface by combining it with micro/nano manufacturing technology. Characteristic features and possibilities of the engineering surface are discussed in detail. This paper reviews studies on micro/nano fabrication technologies for advanced materials and evaluation technology for surface...
The deep-drawing of austenitic stainless steel AISI 304 provides a considerable challenge for production engineers. A major problem in such processes is adhesive tool wear which is often prevented using chlorous mineral oils. The aim of this work was to replace these hazardous lubricants with biodegradable, rape oil based fluids. For that purpose a modified triglyceride named HIGTO(I) is used in combination...
A new direct observation method, which is based on an optical microscopy and a conventional fluorescence method, is developed in order to measure the oil film thickness at the interface between the tool and the workpiece in lubricated upsetting. The oil film thickness is measured using this method. The oil film thickness and the distribution at the interface during lubricated upsetting can be measured...
The trapping behavior of liquid lubricant and contact behavior of asperities at the workpiece–tool interface during upsetting and indentation are observed directly using a compression subpress which consists of a transparent die made of sapphire, a microscope with a CCD camera and a video system. The experiments are carried out without lubricant and with lubricant. Specimens used are commercially...
Tribochemical properties are an essential component of the efficiency of metal forming lubricants. Their understanding, a basis for the selection of adequate additives, heavily relies on surface analytical techniques. In the last ten years, we have applied time-of-flight secondary ion mass spectroscopy (ToF-SIMS) to the analysis of the reactions of strip surfaces with typical additives of cold strip...
As the tribological conditions between tool and workpiece in metal working are of greatest importance for process feasibility and process quality this is even more true when the process is scaled from conventional down to micro dimensions. As can be shown by scaled friction tests the friction is increased by a factor of 20 and more which will have a distinct impact on all factors characterising the...
This paper shows that a dispersion type functional fluid and AC electric field may be used to control the distribution of abrasives in free-abrasive polishing and to improve surface roughness and finishing time. In the case of polishing conductive materials, such as cemented carbide, an AC electric field created by a mono-pole electrode has concentrated abrasives in the polishing area. To obtain a...
Industries and researchers are trying to reduce the use of coolant lubricant fluids in metal cutting to obtain safety, environmental and economical benefits. The aim of this research is to determine if the minimal quantity lubrication (MQL) technique in turning gives some advantages in terms of tool wear reduction. This paper reports the results obtained from turning tests and SEM analysis of tools,...
Ball-on-plate sliding friction experiments were designed and performed to show the possibility of local friction control by electrochemical methods. By partitioning a metal plate into charged and uncharged zones, the friction coefficient in these zones can be differential when an external voltage is applied during rubbing. It is also possible to achieve differential friction at different locations...
This paper reviews the experimental evidence for what is the nature of the friction contact between chip and tool during continuous chip formation and the historical development of friction models. It considers three separate circumstances of turning: at low speeds when lubricants can reduce friction by partial penetration of the chip–tool contact; at high speeds when thermal softening can provide...
Results from the first attempt to use the laser ablation inductively coupled plasma time of flight mass spectrometry (LA-ICP-TOFMS) in the analysis of tribo-chemical layers associated with metal cutting operations are presented here. It was possible to identify the inclusion products from adhering work material at the tool–chip contact in turning 316L stainless steel with cemented carbide tools. Similarly,...
Effects and mechanisms in minimal quantity lubrication are investigated by use of an intermittent turning process. Especially a difference between minimal quantity lubrication (MQL) and MQL with water is inspected in detail to elucidate boundary film behaviour on the rake face. In order to obtain a good cutting performance by MQL it is considered that two things are needed: (1) an appropriate lubricant,...
A series of experiments was carried out using a rolling-type tribometer to investigate the effects on friction behavior of the entraining velocity of the lubricant at the inlet to the contact zone (V) and sliding velocity during deformation (ΔV). Experiments with stainless steel sheets of two different surface roughnesses showed that the variations in the friction coefficient with entraining velocity...
This paper reports a study on the most significant laboratory characterization tests for the performance assessment of innovative coatings for cutting tools, in order to obtain reliable forecasts over their machining behaviour.Ball-erosion tests, Rockwell C indentation, scratch test, ball-on-disc test at room temperature and at high-temperature, as well as nanoindentation and roughness measurements...
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