Search results for "Steel"
showing 10 items of 338 documents
Tool Failure in Sequential Cutting of two Different Materials
1985
In this paper the authors show that the premature tool breakage, characteristic of interrupted cutting, can be enhanced in sequential cutting of two materials having different mechanical and chemical properties. The results of experimental investigations carried out in turning pieces consisting of medium carbon steel and aluminium alloy show that the time to failure is significatively lower than that occurring in machining only one of the two materials; moreover the morphology of the damage depends by the cutting order. Working with the sequence steel-Al alloy welding phenomena caused by strong deoxidation due to the latter material are observed; these phenomena cause the early development …
Experimental investigation of the cutting temperature when turning with coated indexable inserts
1999
Abstract This paper deals with an experimental investigation into the different factors which influence the temperature which occur at the coating/substrate–chip interface when machining a medium carbon steel and an austenitic stainless steel. Both flat-faced and grooved inserts coated with TiC, TiC/TiN and TiC/Al 2 O 3 /TiN were used. A standard K-type thermocouple embedded in the workpiece was used to convert measured efms to the interfacial temperature. Some optimal coating structures for high speed machining of these steels corresponding to the minimum interface temperature were selected. In particular, it was observed that by the proper selection of the thermal properties of the coatin…
Friction behaviour of heat isolating coatings in machining: mechanical, thermal and energy-based considerations
2003
Abstract This paper deals with possible modifications of the frictional behaviour exhibited during the cutting process resulting from the influence of the most-commonly used heat isolating coatings deposited on a WC-Co carbide substrate. For this study, three- and four-layered coatings with intermediate Al 2 O 3 ceramic layer and a monolayer TiAlN coating, which offer superior thermal protection of the carbide substrate, were examined. Orthogonal cutting tests were carried out by end-turning medium carbon steel and austenitic stainless steel workpieces. The experimental study was aimed at determining the fundamental frictional characteristics: dimensions of the tool-chip contact area, the f…
Fatigue crack initiation and subsequent crack growth in fillet welded steel joints
2019
Abstract The fatigue damage evolution in fillet welded steel joints where cracks are emanating from the weld toe is investigated. Based on existing experimental data for as-welded joints including crack depth measurements of the early crack growth it is proposed to make a distinction between the crack initiation phase and the subsequent crack growth phase. The welded detail in question is an F class detail with plate thickness 25 mm made of medium strength carbon steel. It is found that the crack initiation phase defined at a crack depth of 0.1 mm is close to 25% of the fatigue life even at a relatively high constant stress range of 150 MPa. At lower stress ranges it is concluded that the i…
Comparison of the friction and wear properties of titanium and oxidised titanium in dry sliding against sintered high speed steel HS18-0-1 and agains…
2005
Abstract The paper presents the results of conformal pin-on-disc tribological tests concerning the hard oxidised zone, α-Ti(O), created at the surface of a titanium specimens sliding against the sintered and hardened up to 850 HV30, Grade T1 high speed steel (HS18-0-1) counterspecimens. Comparison with the results obtained for the tests performed against hardened up to 620 HV30 C45 carbon steel counterspecimens has been done. Testing was carried out at room temperature and at unlubricated conditions. After tests the structures and compositions of the worn surfaces and wear debris were a subject of LOM, SEM observations and X-ray microanalyses. In comparison with the baseline—the Ti/T1 HSS c…
Prediction of Tool Wear Progress in Machining of Carbon Steel using different Tool Wear Mechanismsl
2008
In this paper the prediction of tool wear on carbide uncoated tools was taken into account. In particular, two different tool wear models based on the diffusion mechanism and on the abrasion mechanism were considered. The calibration of the utilized models was done using the results obtained by experimental analysis performed on an orthogonally machined AISI 1020 tube. Once the calibration was executed, numerical simulations, for both the utilized tool wear models, were simultaneously performed with the aim to test the capability of the proposed numerical procedure. The comparison between the two tool wear mechanisms for predicting the flank tool wear is discussed in the paper.
The role of coatings in controlling the cutting process when turning with coated indexable inserts
1998
Abstract This paper is concerned with the variations in the specific cutting pressure and the tool–chip interface temperature that occur when machining a medium carbon steel and an austenitic stainless steel with TiC-, TiC/TiN- and TiC/Al2O3/TiN- coated inserts. Extensive experimental studies involving the cutting force and the interface temperature were performed. A standard thermocouple embedded in the workpiece was used to determine the cutting temperature. Two new parameters were introduced in order to compare both the mechanical and thermal loadings of the tool–chip contact for coated flat-faced and grooved inserts. Some optimal coating structures for high speed machining of these stee…
Friction and wear properties of titanium and oxidised titanium in dry sliding against hardened C45 steel
2004
Abstract The aim of the paper is to present the results of conformal pin-on-disc tribological tests concerning the hard oxidised zone created in superficial layer of a titanium specimen sliding against the hardened to a hardness of 690 HV carbon C45 steel counterspecimen. Tribological testing was carried out at room temperature and at unlubricated conditions. After tests the structures and chemical compositions of the wear debris and worn surfaces were a subject of SEM and X-ray investigations. In comparison with the baseline the technical quality titanium/C45 steel couple, the wear and lifetime performance of the oxidised titanium/steel C45couple was markedly superior. Dominant wear debris…
Study of Coating/Work Material Interaction in Turning with Chip Forming Inserts
1997
This paper presents some interesting and novel results of an experimental study on the influence of the coating structure on the behaviour of the tribo-contact between the tool and the chip. The experiments involved TiC, TiC/TiN and TiC/Al2O3/TiN — coated flat-faced and grooved inserts in conjunction with a medium carbon steel and an austenitic stainless steel. Extensive experimental studies involving the cutting force and the tool-chip interface temperature were carried out. Two new parameters were introduced in order to compare both the mechanical and thermal loadings of the tool-chip contact for the two shapes of the rake face. Some optimal coating structures for high speed machining of …
Anodic growth of passive layers on steel rebars in an alkaline medium simulating the concrete pores
2006
Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) techniques have been used to study passive layers anodically grown on steel rebars in an aqueous alkaline solution simulating the electrolyte of the concrete pores. Nyquist diagrams recorded by EIS at the different stabilization potentials show a diffusional tail at low frequencies. The analysis of the impedance measurements has been made by means of an equivalent circuit with a Warburg component and within the framework of the point defect model (PDM) theory. It is observed that the calculated concentration of vacancies is a function of the potential in accordance with the theoretical prediction of the PDM.