scholarly journals PERFORMANCE OF COATED CUTTING TOOLS IN MACHINING: A REVIEW

2020 ◽  
Author(s):  
Rukmini Srikant Revuru ◽  
Vamsi Krishna Pasam ◽  
Nageswara Rao Posinasetti
Keyword(s):  
High Temperatures ◽  
Elevated Temperatures ◽  
Materials Science ◽  
Cutting Tools ◽  
High Strength ◽  
Premature Failure ◽  
Aerospace Applications ◽  
Coated Tools ◽  
Intermediate Layers ◽  
Carbide Inserts

Rapid advances in materials science have prompted the development of materials and alloys of enhanced properties like high strength, hardness, etc. Though these alloys are beneficial in their applications, their machining is difficult. For instance, Inconel 718, a nickel-based alloy, is used in several aerospace applications. This alloy can retain its strength at high temperatures up to 750℃. However, machining Inconel is a problem due to its poor machinability. Similarly, titanium alloys are not very hard but react with tools at high temperatures and lead to their premature failure. Carbide inserts are commonly used as cutting tools in the industry. Carbide tools are manufactured using powder metallurgy technique and possess high strength and hardness, even at elevated temperatures. However, these tools are not effective in machining of “difficult-to-machine” materials and have very short life. In light of this, coated tools have evolved. The cutting tools are coated using very hard, non-reacting material and sometimes a solid lubricant. The coatings are made usually by using PVD or CVD techniques. Often, intermediate layers are provided to improve adhesion between the substrate and the actual coating. Coated tools have better resistance to temperatures and hence, better tool life compared to the regular cutting tools. This paper deals with the evolution of the technology of coated tools. Different types of coatings, their advantages/limitations and efficacy of coated tools in machining are reviewed and discussed.

EASTERN STAINLESS TYPE 310S

Alloy Digest ◽  
1984 ◽  
Vol 33 (8) ◽  
Keyword(s):  
High Temperatures ◽  
Elevated Temperatures ◽  
High Strength ◽  
Heat Treating ◽  
Oil Refining ◽  
Steel Company ◽  
Plant Equipment ◽  
The Many ◽  
Corrosion And Oxidation ◽  
Refining Equipment

Abstract EASTERN STAINLESS TYPE 310S has high resistance to corrosion and oxidation at high temperatures. It also has high strength at elevated temperatures. Thus it is especially suitable for service at high temperatures. It is very ductile and can be welded readily. Among the many applications for Type 310S, a few typical uses include annealing boxes, chemical plant equipment, fire box sheets, furnace linings, heat exchangers, oil-refining equipment, kiln linings and tube hangers. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-450. Producer or source: Eastern Stainless Steel Company.

Fundamental Properties of Intermetallic Compounds

MRS Bulletin ◽  
1995 ◽  
Vol 20 (8) ◽  
pp. 33-39 ◽  
Author(s):  
Morihiko Nakamura
Keyword(s):  
Intermetallic Compounds ◽  
High Temperatures ◽  
Volume Fraction ◽  
Cutting Tools ◽  
High Strength ◽  
Strict Sense ◽  
Maraging Steels ◽  
Hard Metals ◽  
Airplane Engine ◽  
Interatomic Bonding

More than 25 years have passed since Intermetallic Compounds, edited by Westbrook, was published. Since that time, enormous advances have been made in the understanding and usage of intermetallic compounds. It is known that intermetallic compounds are generally brittle. Thus, alloys that contain intermetallics may also be brittle. However, many intermetallic compounds are known to have extraordinary functions and characteristics that are not observed in ordinary metals and alloys. Thus, they function as magnetic materials, superconductors, semiconductors, hydrogen absorbing alloys, shape memory alloys, and so on.Many high-strength structural alloys like maraging steels and duralumins are strengthened by fine precipitates of intermetallic phases. Nickel-based superalloys, which are used for airplane-engine parts, contain 60-70% of Ni3Al-based intermetallics by volume fraction and exhibit high strength at high temperatures. Hard metals, which are used for cutting tools, are composed of a large amount of hard but brittle intermetallics like WC and a small amount of ductile cobalt. Intermetallic compounds like TiAl are also investigated for their applications as structural materials where high strength at high temperatures is required.In a strict sense, intermetallic compounds are composed of two or more metallic elements. In a wider sense, they are composed of metallic and/or semimetallic elements. Each is characterized by an ordered arrangement of two or more kinds of atoms, that is, the formation of a superlattice, and have various kinds of interatomic bonding, ranging from metallic to covalent or ionic bonding. The ordering of atoms and the strong interatomic bonding result in many attractive properties for intermetallic compounds.

Residual Strength of Super High Strength Concrete Used Stone-Chip after Exposure to High Temperatures

2011 ◽  
Vol 374-377 ◽  
pp. 2456-2460
Author(s):  
Guo Can Chen ◽  
Zhi Sheng Xu ◽  
Wei Hong Tang
Keyword(s):  
High Temperatures ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
Experimental Studies ◽  
High Strength ◽  
Normal Strength Concrete ◽  
Strength Concrete ◽  
Fine Aggregates ◽  
Normal Strength ◽  
Peak Value

This paper presents the results of experimental studies on the residual compressive strength of concrete produced with stone-chip as fine aggregates with the compressive strengths of unheated specimen ranging from 45.8 to 129.5MPa after exposure to high temperatures and the experimental parameters being the temperature, admixtures, and PP fiber. Specimens were heated in an electric furnace for 4h to high temperatures ranging from 150 to 960°C. Experimental results showed that the compressive strengths of super high strength concrete used stone-chip (abbreviated to SHSCUS) and normal strength concrete used stone-chip (abbreviated to NSCUS) after exposure to elevated temperatures changed in the manners different from that of normal strength concrete, which reached their peak at about 400°C, and the presence of pp fibers in SHSCUS concrete could reduce the risk of spalling at the high temperatures and the peak value after fire.

Nanocrystalline Diamond Coated Tool Performance in Machining of LM6 Aluminium Alloy/Alumina MMC

2015 ◽  
Author(s):  
Ramasubramanian Kannan ◽  
Arunachalam Narayanaperumal ◽  
Mamidanna Sri Ramachandra Rao
Keyword(s):  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Weight Ratio ◽  
High Hardness ◽  
High Strength ◽  
Matrix Composites ◽  
Aerospace Applications ◽  
Coated Tools ◽  
Nano Crystalline ◽  
Improved Performance

Aluminium based metal matrix composites (MMC) gain its importance in automotive and aerospace applications due to their high strength to low weight ratio, which leads to reduced fuel consumption and improved performance. However the usage of MMC is limited due to its poor machinability. The presence of hard reinforcing particles in MMC makes these materials difficult to machine. A cutting tool with high hardness and low coefficient of friction is required for machining this MMC material effectively. In this paper a comparative study on machinability of different coated tools on LM6 aluminum alloy/alumina MMC are conducted and presented. Experimental results on tool wear, cutting force and surface finish indicate that nano-crystalline diamond coated tools (NCD) outperform the other commercially available coated tools for machining this metal matrix composites.

High Strength Aluminium Sheet Metal Joining by Resistance Spot Welding

2013 ◽  
Vol 765 ◽  
pp. 761-765 ◽  
Author(s):  
Rudolf Gradinger ◽  
Nikolay Sotirov ◽  
Gottfried Rettenbacher ◽  
Christoph Pangerl ◽  
Philipp Dörner ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Spot Welding ◽  
Elevated Temperatures ◽  
Stable Process ◽  
High Strength ◽  
Automotive Body ◽  
Aerospace Applications ◽  
Joining Technology ◽  
Body In White ◽  
Opening Up

Aluminium AA7075 is well known as extrusions, plate or sheet metal predominately in aerospace applications. The continuing efforts for reducing the weight but still maintaining the safety of vehicle structures are opening up the way for this alloy in automotive applications. Since this branch is very different to space as well as aircraft industries in manufacturing methods, costs and production numbers, the development of appropriate processes is necessary. After showing a high potential for deep drawing of AA7075 sheets under elevated temperatures, the joining technology options are now under investigation too. Since spot welding is very common in automotive body-in-white manufacturing, an innovative version of this process is evaluated for applicability for welding AA7075-T6 sheets to each other and to proven automotive aluminium alloys. The results of sample weldments, including mechanical static strength, micrographs, hardness, radiography and parameters for a stable process range, are presented.

scholarly journals Dynamic Tensile Properties and Energy Dissipation of High-Strength Concrete after Exposure to Elevated Temperatures

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5313 ◽  
Author(s):  
Nao Lv ◽  
Hai-bo Wang ◽  
Qi Zong ◽  
Meng-xiang Wang ◽  
Bing Cheng
Keyword(s):  
Tensile Strength ◽  
Strain Rate ◽  
High Temperatures ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
Coarse Aggregate ◽  
High Strength ◽  
Dynamic Tensile Strength ◽  
Strength Concrete ◽  
Propagation Law

In view of the devastating outcomes of fires and explosions, it is imperative to research the dynamic responses of concrete structures at high temperatures. For this purpose, the effects of the strain rate and high temperatures on the dynamic tension behavior and energy characteristics of high-strength concrete were investigated in this paper. Dynamic tests were conducted on high-strength concrete after exposure to the temperatures of 200, 400, and 600 °C by utilizing a 74 mm diameter split Hopkinson pressure bar (SHPB) apparatus. We found that the quasi-static and dynamic tensile strength of high-strength concrete gradually decreased and that the damage degree rose sharply with the rise of temperature. The dynamic tensile strength and specific energy absorption of high-strength concrete had a significant strain rate effect. The crack propagation law gradually changed from directly passing through the coarse aggregate to extending along the bonding surface between the coarse aggregate and the mortar matrix with the elevation of temperature. When designing the material ratio, materials with high-temperature resistance and high tensile strength should be added to strengthen the bond between the mortar and the aggregate and to change the failure mode of the structure to resist the softening effect of temperature.

scholarly journals ’Quenching and Partitioning’ - An In Situ Approach to Characterize the Process Kinetics and the Final Microstructure of TRIP-Assisted Steel

2011 ◽  
Vol 409 ◽  
pp. 713-718 ◽  
Author(s):  
Thomas Rieger ◽  
Klaus Herrmann ◽  
Dagmar Carmele ◽  
Stephan Meyer ◽  
Thomas Lippmann ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Elevated Temperatures ◽  
Materials Science ◽  
High Strength ◽  
Quantitative Information ◽  
Characterization Methods ◽  
Quenching And Partitioning ◽  
X Ray ◽  
Final Microstructure

The ‘Quenching and Partitioning’ (Q&P) concept aims to increase the strength level of conventional TRIP-assisted advanced high strength steel (AHSS) by replacing ferritic constituents by tempered martensite. The Q&P heat treatment process involves austenitization and interrupted quenching followed by carbon partitioning from martensite to austenite at elevated temperatures. The final microstructure is traditionally investigated at room temperature after metallographic preparation by microscopy and x-ray analysis with laboratory tubes. Besides other disadvantages the established characterization methods are not adequate to observe the development of the microstructure during Q&P treatment. In the present work the microstructural evolution during Q&P processing was monitored by in-situ diffraction experiments using very hard (100 keV) synchrotron x-ray radiation. Debye-Scherrer rings were recorded as a function of time and temperature during the heat treatment in a state-of-the-art dilatometer (type Bähr DIL805AD) at the Engineering Materials Science beamline HARWI-II (HZG outstation at Deutsches Elektronensynchrotron (DESY), Hamburg). The diffraction patterns contain quantitative information on the phases present in the sample (for more details cf. Abstract Carmele et al, this conference). The evolution of the austenite phase fraction during the partitioning treatment at the quench temperature (1-step Q&P) is discussed exemplarily for a Si-based TRIP steel with additions of Ni.

scholarly journals Characterizations of Lamellar Interfaces and Segregations in a PST-TiAl Intermetallic Alloy by an Analytical Scanning Transmission Electron Microscope

2000 ◽  
Vol 652 ◽  
Author(s):  
Wei Zhao ◽  
David E. Luzzi
Keyword(s):  
High Temperatures ◽  
Titanium Aluminide ◽  
Elevated Temperatures ◽  
High Strength ◽  
Scanning Transmission Electron Microscope ◽  
Zone Method ◽  
Specific Strength ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Lamellar Interfaces

ABSTRACTPolysynthetically-twinned titanium aluminide (PST-TiAl), a fully lamellar γTiAl + α2-Ti3Al dual-phase alloy, is under evaluation for applications in rotary components in aircraft and automobile industries due to its high specific strength, and a high strength-retention capability at elevated-temperatures. However, the low ductility at room- to mid-high temperatures of the material hinders its application. Additions of certain tertiary elements to the binary TiAl system appear to improve the ductility at room- to mid-high temperatures, thus a balance among strength, ductility, and fracture toughness can be expected. In this article, segregation of tertiary elements to the lamellar interfaces is investigated. Single crystals of a TiAl with 0.6% atomic percentage tertiary additions are grown by an optical float-zone method. Segregation to the lamellar interfaces and the microstructure of the interfaces are investigated. Structures of the lamellar interfaces are characterized, and microchemistry and distribution habits of these elements along the γ+α2 lamellar boundaries as well as the γ-γ lamellar and domain boundaries are analyzed.

Characteristics of Acoustic Emission Signals in Machining Using Diamond Coated Tools

2008 ◽  
Author(s):  
Jianwen Hu ◽  
Feng Qin ◽  
Kevin Chou ◽  
Raymond G. Thompson
Keyword(s):  
Acoustic Emission ◽  
Cutting Tools ◽  
Polycrystalline Diamond ◽  
High Strength ◽  
Cost Effective ◽  
Fast Fourier Transformation ◽  
Coated Tools ◽  
Coating Delamination ◽  
Pcd Tools ◽  
Ae Signals

Diamond coated cutting tools have been pursued as a cost-effective substitute to brazed polycrystalline diamond (PCD) tools in applications such as machining high-strength and lightweight materials. However, coating delamination has been known as the major failure mode of diamond coated tools, which terminates tool life prematurely. Once delamination failure occurs, the tool substrate often subjects to severe abrasive wear leading to catastrophic tool failures that imparts the part quality and interrupts machining operations. Hence, accurate detections and forecasts of coating delamination events can prevent production loss and assist process planning. In this study, the characteristics of acoustic emission (AE) signals when machining a high-strength aluminum alloy and a composite using diamond coated cutting tools were investigated. The AE signals were analyzed in both time and frequency domains at various machining conditions and different cutting times. It was found that AE root-mean-square values decrease considerably once coating delamination occurs. The results also indicate a correlation between the tool condition and fast Fourier transformation (FFT) spectra of AE raw data. In addition, the machining experiments implied that it may be feasible to use AE signals to monitor the condition of diamond coated tools during machining.

scholarly journals Experimental Study of Wear Mechanisms of Cemented Carbide in the Turning of Ti6Al4V

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2822 ◽  
Author(s):  
Sara Saketi ◽  
Stina Odelros ◽  
Jonas Östby ◽  
Mikael Olsson
Keyword(s):  
High Resolution ◽  
Wear Mechanism ◽  
Elevated Temperatures ◽  
Flank Wear ◽  
Chemical Reactivity ◽  
High Strength ◽  
Cemented Carbide ◽  
Diffusion Wear ◽  
Carbide Inserts ◽  
Cutting Speeds

Titanium and titanium alloys such as Ti-6Al-4V are generally considered as difficult-to-machine materials. This is mainly due to their high chemical reactivity, poor thermal conductivity, and high strength, which is maintained at elevated temperatures. As a result, the cutting tool is exposed to rather extreme contact conditions resulting in plastic deformation and wear. In the present work, the mechanisms behind the crater and flank wear of uncoated cemented carbide inserts in the turning of Ti6Al4V are characterized using high-resolution scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and high-resolution Auger electron spectroscopy (AES).The results show that, for combinations of low cutting speeds and feeds, crater and flank wear were found to be controlled by an attrition wear mechanism, while for combinations of medium to high cutting speeds and feeds, a diffusion wear mechanism was found to control the wear. For the latter combinations, high-resolution SEM and AES analysis reveal the formation of an approximately 100 nm thick carbon-depleted tungsten carbide (WC)-layer at the cemented carbide/Ti6Al4V interface due to the diffusion of carbon into the adhered build-up layers of work material on the rake and flank surfaces.

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