Carbide Inserts,Cutting Tool, Turning Insert, Milling Insert

Minimum quantity lubrication (MQL) has great potential for assisting in machining a wide spectrum of materials. As manufacturers continuously seek to reduce manufacturing costs, waste and improve health and safety profiles, this technology can help in the drive to get there.

So says Optis, a joint venture between TechSolve and Castrol. According to Optis, flood coolant uses as much as 60,000 ml of fluid per hour, while MQL typically uses less than 500 ml per hour. This is due to the coating of the interface between the tool and the material being cut with a thin film of lubricant, preventing heat build-up caused by friction. This significantly reduces the amount of fluid that needs to be procured, maintained and disposed of, saving money, manpower, and health and safety issues associated with residual fluid and contaminated chips.

When properly applied, whether externally or through the tool, MQL can lead to improved surface finish and increased tool life. It also has a positive impact on emissions and waste, boosting a facility’s overall health, safety and environmental profile.

According to Optis, the cumulative cost of cutting fluid can total as much as 15 percent of a part’s total production cost. Therefore, minimizing its use has major cost-efficiency implications for manufacturers. Also, there are many routes to doing so with many cutting operations primed to benefit from MQL, including turning, milling, drilling, circular and band sawing, reaming, tapping, routing and broaching.

However, despite the opportunities and benefits MQL machining can offer, there are still challenges to overcome and some key considerations in implementation:

MQL does not have comparable chip evacuation abilities to those of wet machining.MQL is still not well suited for deep-hole drilling, energy-intensive processes such as grinding, special operations like honing and small-hole drilling, or for difficult-to-machine materials such as titanium and nickel-based alloys.MQL CNC Inserts still produces a very fine mist, which can be more difficult to filter.MQL implementation may require changes to the machine tool and processing strategy.

Despite these challenges, Optis says MQL provides a cleaner, greener alternative to classic fluid supply, on which could take manufacturers forward in embracing sustainability initiatives and implementing “Factory of the Future” capabilities. However, industry update has been relatively low so far. This reticence may be due to how counterintuitive it seems that using less fluid will yield the same cooling and lubricating properties as traditional flood or high-pressure systems. The fluid itself must be carefully selected based on the material that’s being cut, and its application must be carefully considered based on tooling , type of operation, cutting parameters and machine tool being used, the company says.Machining Inserts

The Carbide Inserts Website: https://www.estoolcarbide.com/indexable-inserts/cnmg-insert/

Design reviews and feedback sessions with the faculty, students, doctors, scientists, and industry partners were conducted remotely to practice good social distancing (Image credit: Penn State College of Medicine).

It’s hard to believe that it has been about two months since our lives were turned upside down by the coronavirus. As I wrote in my last column, the move to online classes at Penn State combined with seeing and sharing stories about 3D printed personal protective equipment (PPE) with my network of colleagues, companies and healthcare workers at Penn State’s Milton S. Hershey Medical Center (PSHMC) landed me right smack in the middle of the fight against COVID-19.

Before I knew it, our informal “grass roots” efforts to help 3D print PPE connected with the university’s senior leadership push to ready the team at SNMG Insert PSHMC for the impending surge in COVID-19 cases. I was asked to lead the effort. We named it the Manufacturing and Sterilization for COVID-19 (MASC) Initiative. This limited our work to meeting the manufacturing and sterilization needs required to protect healthcare workers against COVID-19. Patient screening, vaccine development, antibody testing, and so on were thus out of scope for us.

Like many similar efforts springing up at universities and community maker spaces around the country, our first victory was the 3D printed face shields. We used the Prusa face shield design developed and open sourced by the team in Czechoslovakia. We redesigned it and optimized the processing parameters to reduce the build time by 60%, getting it well under one hour. Still, if you want to make 1,000 (or more) face shields WNMG Insert per day, you need at least 50 3D printers running all out with minimal build failures and plenty of material on hand. As such, 3D printing is a good stopgap when there is a shortage of manufacturing capacity; but faster production methods were still needed to meet the looming demand.

The 3D printed headband was only one part of the shield, and we reached out in our network to find available laser cutters and polycarbonate sheet to make the rest of the face shield design. We found that laser cutters were in short supply in our area, and polycarbonate sheet was soon sold out around the country; so, we pivoted to the three-hole-punched version like everyone else and used transparency sheets to make the face shield. Unfortunately, as you can imagine, a face shield with a three-hole-punched transparency sheet will not meet FDA regulations, and it certainly does not pass the ANSI drop-test requirements for protective eyewear (ANSI Z871.1).

Dozens of filtration mask designs and material options were quickly prototyped, evaluated and revised thanks to 3D printing (Image credit: Matt Briddell, Penn State Center for Medical Innovation).

Luckily, the rapidly expanding network of our MASC Initiative included several companies that were able to change their manufacturing lines or set up entirely new lines to produce face shields, in volume, to meet the growing demands at PSHMC and other local hospitals. For instance, the team at Actuated Medical Inc. stood up an entirely new production line in their GMP-compliant facility in less than seven days to make reusable face shields that were compliant with relevant ANSI standards using more traditional manufacturing methods. Meanwhile, Universal Protective Packaging Inc. near PSHMC transformed one of its production lines to start cranking out several thousand face shields per day using more traditional manufacturing and assembly methods. Both companies are now supplying healthcare workers regionally while also meeting the rising demands from nursing homes, public works crews, police services and individuals.

While one of our teams was solving the face shield problem, another team was using 3D printing to prototype and test all of the N95-like filtration masks that were being shared online and open sourced. Based on feedback from doctors and clinicians at PSHMC, mask designs were quickly modified and revised to improve fit, comfort and breathability, and new prototypes were fabricated overnight and tested the next day.

This rapid design iteration and feedback cycle is where 3D printing really excels, and it became even more critical as shortages in supplies emerged — something we did not appreciate at first, but something that drove many of our design decisions. For instance, filtration material could no longer be sourced in the United States, and alternative supplies of filtration media were quickly exhausted from the shelves of hardware stores. This meant designing a smaller opening in the mask to use less filtration material for the limited supply we had, but this reduced the effective surface area, which reduced the filtering capability of the mask.

A test was developed to evaluate the filtration capabilities of different types and amounts of filtration material, and the mask team determined that adding three or four more layers would satisfy the requirements for N95 masks (although we have not been able to certify this given the backlog at NIOSH testing labs right now). Unfortunately, adding that much material made it too hard to breathe through the mask, and so, we went back to the drawing board.

As of this writing, we have solved the filtration problem with some creativity and old-fashioned engineering, including a bit of advice from a fluid dynamics expert we pulled onto the team, and it looks like we may have found a viable solution that can be mass produced. This was accomplished by engaging an industry partner specializing in tooling and injection molding on the team. They have provided invaluable advice as we modified designs and started to think about scaling up production. As you might guess, 3D printing can make nearly any geometry that is injection molded, but the reverse is not true. Complex features that are easily 3D printed will likely lead to exorbitant tooling costs for injection molding — but more on that next month.

Note on Open-Source PPE

Despite its many advantages, keep in mind that no open-source 3D printed PPE has received FDA or NIOSH approval for protecting healthcare workers. Regulatory guidelines have shifted a lot, but make sure that you know and follow the Health Guidelines for 3D Printing Medical Devices and PPE for COVID-19 Response developed by the COVID-19 Healthcare Coalition or other reputable source.

The Carbide Inserts Website: https://www.estoolcarbide.com/product/tnmg-carbide-inserts-for-stainless-steel-turning-inserts-p-1187/

It is not only our own vision that is incapable of isolating spark generation in the sinker EDM process. Most cameras cannot keep up with a production rate of up to 30,000 sparks per second, which, believe it or not, happens one at a time. Photo: Adam Wysuph, MC Machinery.

The frame rates per second (fps) for movies and television are typically standardized at 24 and 30 fps, respectively. Because each frame moves too quickly for humans to visually isolate, we perceive the collection of individual frames as a continuous moving picture.

Every EDM operation begins with a central question: Which waveform will best produce the desired result? The answer, of course, depends on the Cutting Inserts workpiece material. The conductivity of different metals, as well as their ability to absorb heat, are key determining factors. Photo: Adam Wysuph, MC Machinery

A similar illusion is at work with sinker electrical discharge machining (EDM) equipment, featured in the image above. Of course, the EDM process involves metalcutting via electrical discharges, or sparks, between an electrode and the workpiece in a dielectric liquid. The sparks produced by the sinker EDM process — anywhere from 500 to 30,000 sparks per second — seem to appear simultaneously. In truth, these rapid-fire sparks are produced one at a time. If we cannot isolate a frame of moving film, clearly the EDM process is far too fast for us to keep up with what is happening before our eyes.

While our perception betrays us, it is still Carbide Inserts important that we understand this fact in order to properly control the EDM process.

Understanding and optimizing sinker EDM was the premise of a technical presentation given by Pat Crownhart at MC Machinery Systems’ open house this past fall. Mr. Crownhart is the company’s sinker EDM product manager — a title that short-shrifts his deep expertise on the electromechanical functions taking place during an EDM process. Since Mr. Crownhart’s presentation left most of his audience in the dust after just a few slides, I touched base with him recently to get a better understanding of what he considers to be the central tenets of sinker EDM technology.

Think of each EDM spark that is discharged as a shovel of material removed from the part. The conductivity of different metals as well as their ability to absorb heat are key determining factors for the type of “shovel” that should be used. Image: Pat Crownhart, MC Machinery

Choose the Right Shovel

“Think of every EDM spark that is discharged as a shovel of material removed from the part,” Mr. Crownhart says. The sizes and shapes of the shovels — each designed to perform a specific task — can be controlled by manipulating how electrons travel across the gap between the electrode and the workpiece.

Every EDM operation begins with a central question: Which waveform — or which shape of shovel — will best produce the desired result? The answer depends on the workpiece material. The conductivity of different metals as well as their ability to absorb heat are key determining factors for the type of “shovel” that should be used.

Mr. Crownhart says that the most common shovel shape, the square waveform (referred to as the transistor pulse or TP waveform on EDM machines made by Mitsubishi Electric, which owns MC Machinery Systems) is used for as much as 90% of sinker EDM work due mainly to its versatility across a range of materials. Square waveforms produce a lot of heat by ramping up the amperage quickly. Since EDM equipment in the United States typically features graphite electrodes that are capable to withstanding high temperatures, most of these machines use the TP circuit for day-to-day operations.

If the amperage waveform represents the EDM shovel’s shape, voltage can be likened to its handle — how long can the shovel reach? Voltage initiates the spark, but if it takes too long to do so because of electrode contamination or other reasons, the efficiency of the EDM process drops. The machine makes small servo adjustments to location each time a spark is produced, and changing voltage parameters — i.e. changing the gap length between the electrode and the workpiece — will impact the operation, for better or worse. “When you change the gap, you change how far that spark will travel,” Mr. Crownhart says. “You can safely change voltage to a certain degree, but because so many adjustments are being made so quickly, you need to understand the role voltage plays or risk ruining the part.”

Modern sinker EDM equipment makes small adjustments with the servo each time a spark is produced. Changing voltage parameters — or the gap length between the electrode and the workpiece — will impact the operation. Image: Pat Crownhart, MC Machinery

Polarity, which for our purposes we’ll describe as the travel direction of the electrons, is another central variable within sinker EDM operations. Before adaptive control became available and then advanced on machines like Mitsubishi Electric’s new SV series, many older machines utilized negative polarity. Without adaptive control, if a direct current does not turn off and instead produces a long spark, you risk damaging your workpiece. Negative polarity induces a fast burn rate (and is still the best option for titanium and some exotic metals), but damage from electrical shorts typically impacts the electrode rather than the workpiece. Positive-polarity sparks — when the electrons flow from the part to the electrode — typically produce less wear on the electrode.

Sparks Are the Enemy

While it may be counterintuitive, sparks are the enemy of the EDM process. Sparks represent heat, and “if you’re just heating it up, you’re really just using a welder,” Mr. Crownhart says. The higher the amperage and the longer the on-time, the more heat that is produced with each discharge. While faster burn rates produce more heat, heat in excess can cause particles to grow on the electrode. In turn, this contamination, or swarf, causes the machine to spark in the same spot continuously, resulting in a poor finish or causing damage to the workpiece.

Here is a Mitsubishi Electric SV12P cutting tunnel gates into H13 steel. Photo: Adam Wysuph, MC Machinery

“That’s why the old adage of EDM was flush, flush, flush,” Mr. Crownhart says. “It is because in the olden days when the electronics weren’t as advanced, it was really important that your contaminants were being broken up and that pressurized fluid was being brought in.” Modern power supplies react to inconsistent sparks and add extra time to allow for cooling, but contamination is still a major consideration with sinker EDM technology. “You can only machine as fast as you’re moving contaminants,” Mr. Crownhart says.

Taken together, these may be basic points to experienced EDM users. But Mr. Crownhart says that he has encountered many users who run EDM purely based on what has worked in the past, without necessarily understanding why a certain setting worked. “It is possible to be more predictive than, ‘This has worked for me in the past so I’ll try it now,’” he says. “With that mindset, you’re just tinkering with settings until you get something to work. The better you understand the process, the faster you can get to the most optimized settings for your job.”

The Carbide Inserts Website: https://www.estoolcarbide.com/product/togt-deep-drilling-inserts-cnc-lathe-cutting-indexable-carbide-drill-insert-p-1207/

Contents hide 1Overview of thermodynamics 2Formation and development of material thermodynamics 3Applications in various fields of material thermodynamics 3.1(1) Traditional steel industry 3.2(2) Metal matrix composites 3.3(3) Nanomaterials 3.4(4) Shape memory alloys 4Trends in material thermodynamics 5ReferencesOverview of thermodynamics

Changes in thermal effects usually accompany all physical, chemical, and metabolic reactions occurring in nature. People’s understanding of the nature of heat has undergone a long and tortuous journey of exploration.

In the early 20th century, Planck, Poincare, Gibbs, and other scientists took macroscopic systems as the object of study, based on the first and second laws of thermodynamics, and defined functions such as enthalpy, entropy, Helmholtz and Gibbs, together with objective properties such as P, V, and T that can be directly measured. After inductive and deductive reasoning, a series of thermodynamic formulas and conclusions were obtained, which were used to solve energy, phase, and reaction. This is the basic framework of classical thermodynamics. The object of classical thermodynamics is the exchange of matter and energy in a system. It is a science constantly approaching the limit, discussing only the equilibrium state before and after the change. It does not involve the microstructure of particles inside the matter.

Boltzmann et al. combined quantum mechanics with classical thermodynamics to form statistical thermodynamics. Statistical thermodynamics belongs to the microscopic-to-macroscopic approach, which starts from the properties of microscopic particles and defines the system or particle’s partition function by finding the statistical probability, which is used as a bridge to establish the connection with the macroscopic properties.

Time is a significant independent variable in thermodynamics, and how to deal with the time variable is a sign to distinguish different levels of thermodynamics. In physics, entropy increase is used to describe the unidirectional nature of time. Thermodynamics studies the possibilities, and kinetics studies the realities, i.e., the rate of change and the mechanism of change. Kinetics is a function of reaction progress versus time, where the behavioral state and output of the system depend only on the starting state and subsequent inputs.

So many phenomena occurring in nature are irreversible processes in nonequilibrium, which drives thermodynamics from equilibrium to nonequilibrium. In the 1950s, Prigogine I, Onsager L, and others formed Non-equilibrium Thermodynamics (NET), and the local equilibrium assumption is the nonequilibrium central assumption of thermodynamics. Among them, Onsager L established the inverse-equilibrium relation of the image-only coefficient in 1931, and Prigogine proposed the principle of minimum entropy increase for nonequilibrium fixed states in 1945, which is applicable to linear nonequilibrium systems close to the equilibrium state. For systems far from equilibrium, the Brussels school led by Progogine established the famous dissipative structure theory after years of efforts, which was later confirmed by some self-organizing phenomena such as cloud street and the Benard convection experiment (see Figure 1). The dissipative structure theory pointed out that open systems far from equilibrium can form ordered states, opening the window of physical science to the life sciences.
At present, thermodynamics is no longer just the science of studying the basic laws of thermal phenomena, it is closely related to systems theory, nonlinear science, life science, and the origin of the universe, and its applications involve physics, chemistry, biology, engineering, and technology, as well as cosmology and social disciplines [1].

Formation and development of material thermodynamics

The progress and development of modern materials science have been supported and helped by thermodynamics, which is the application of classical thermodynamics and statistical thermodynamics theory in the field of materials science, and its formation and development one of the signs of the maturity of materials science.

From the appearance of Gibbs phase law in 1876, H. Roozeboom applied the phase law to multicomponent systems in 1899, Roberts-Austen constructed the initial form of Fe-Fe3C phase diagram in 1900, which provided theoretical support for the study of steel materials; then in the early 20th century, G. Tamman and others established a large number of metal system phase diagrams through experiments In the early 1950s, R. Kikuchi proposed a modern statistical theory of entropy description, which created the conditions for the combination of thermodynamic theory and first principles; in the early 1960s, M. Hillert and others studied the thermodynamics of nonequilibrium systems, which led to the emergence of the field of instability decomposition and enriched the understanding of the formation of material tissues; in the 1970s, L. Kaufman, M. Hillert and others introduced the first phase diagrams for steel materials. . Kaufman, M. Hillert and others advocated the calculation of phase diagram thermodynamics (CALPHAD), which gradually brought materials research into the era of material design according to practical needs [2].

In June 2011, the U.S. announced a $500 million Advanced Manufacturing Partnership, one of the core elements of which is the Materials Genome Initiative (MGI). “The MGI aims to provide the necessary toolset for the development of new materials, reduce the reliance on physical experiments through powerful computational analysis, and significantly accelerate the variety and speed of new materials brought to market by advances in experimentation and characterization, reducing the development cycle from the current 10-20 years to 2-3 years.

Materials thermodynamics studies the melting and solidification of solid materials, solid-state phase transitions, phase equilibrium relationships and compositions, microstructural stability, and the direction and driving force of phase transitions. In order to describe the free energy, enthalpy, entropy, etc. of various types of phases, various image-only or statistical thermodynamic models have been proposed, such as the ideal solute model, the regular solute model, the subregular solute model, the quasi-chemical model, the atomic sum model, the central atom model, the double sub dot model, the variational group model (CVM), the Bragg-Williams approximation, the Bethe approximation, the Ising approximation, Miedema approximation, etc. Diffusion is the main content of kinetic studies, including the formation and growth of nuclei during solidification, as well as homogenization, distribution, and redistribution of solute atoms in the alloy during heat treatment, which can be deduced from Fick’s first and second laws.

Thermodynamic calculations cover a wide range of essential tools for the analysis and understanding of materials science problems: Gm-x diagrams, phase diagrams, TTT curves, CCT curves, etc. Among them, the most successful core application is the phase diagram calculation. Phase diagrams can be divided into three categories based on the methods used to obtain them.

1, experimental phase diagrams: using experimental means (DSC, DTA, T.G., X-ray diffraction, electron probe micro-region composition analysis, etc.), mainly for di- and ternary systems.

2, theoretical phase diagram, also known as the first principle computational phase diagram, does not require any parameters, the use of the Ab initio method to achieve a theoretical, computational phase diagram, only a small number of reports in the design of individual binary and ternary system materials.

3, computational phase diagrams, the core of which is the computer coupling of the theoretical model and thermodynamic database. Most of the internationally famous software adopt CALPHAD mode, including Thermo-Calc, Pandat, FactSage, Mtdata, JMatPro, etc. Most of the descriptions of the free energy of solute in CALPHAD mode adopt the subregular solute model, and the process is shown in Figure 3, which is based on the characteristics of each phase in the system, integrating thermodynamic properties, phase equilibrium data, crystal structure, and other information in one, establish thermodynamic models and free energy expressions, and then calculate the phase diagram based on the thermodynamic conditions of multivariate multi-phase equilibrium, and finally obtain the thermodynamically self-consistent phase diagram of the system and the optimized parameters describing the thermodynamic properties of each phase.

For example, Cui-Ping Wang, Xing-Jun Liu, Ikuo Onuma et al. evaluated the thermodynamic parameters of each phase of the Cu-Ni-Sn ternary system using the CALPHAD method. Their calculated results agreed well with the experimental values, as shown in Fig. 4. They also calculated the ordered-disordered transition of the bcc phase and the solubility gap of the fcc phase in this ternary system, which is important for the development of high-strength and high-conductivity new Cu-Sn systems using precipitation enhancement and Spinodal decomposition. And high conductivity of new Cu-based alloys using Spinodal decomposition [3].
The kinetic calculations are based on thermodynamic calculations, introducing a diffusion kinetic model with time as a variable and an atomic mobility database, and obtaining the relationship between the thermodynamic state of the material with time through a large number of iterative operations.

Applications in various fields of material thermodynamics

In any system, the thermodynamic, kinetic, and material structure aspects are closely related. The microstructure and thermodynamic properties of metallic materials influence the evolution of generated phases and microstructures during solidification and heat treatment. For example, for Al-Cu system alloys, solute atoms are supersaturated and precipitated during solid solution, causing spherically symmetric distortion; during age-hardening, G.P. Zone is formed first, followed by aggregation and ordering of solute atoms on low index crystallographic planes, eventually generating a non-co-grained theta (Al2Cu) equilibrium phase. When the size of the phase generated during solidification or homogenization is larger than 0.5 μm, dislocation plugging occurs at the interface when loaded and becomes a source of cracks; when the size is between 0.005 and 0.05 μm and has a fine diffuse distribution, it can hinder recrystallization and grain growth. Of course, thermal and kinetic theories have now penetrated into all fields of materials and become an effective theoretical guide and necessary analytical tool.

(1) Traditional steel industry

The General Research Institute of Iron and Steel, as the largest professional steel material research and development institution in China, was one of the first to introduce thermodynamic calculation methods and software and has achieved fruitful research results in nickel-saving stainless steel design, V-N microalloying technology, and 9 Ni low-temperature steel for LNG [4].

(2) Metal matrix composites

Fan Tongxiang, Li Jianguo, Sun Zuqing, and others have done a lot of research on the control of the reaction between the reinforcing phase and the matrix interface, the selection of the reaction autogenous reinforcing phase type, the design of the composite system and the preparation process using thermodynamic and kinetic models [5]. And an example of the application is that the calculations of thermodynamic of materials help a lot in developing the Sinter HIP process for tungsten carbide production.

(3) Nanomaterials

In 2000, Chamberlin of Arizona State University, USA, used the term Nanothermodynamics in the study of the critical behavior of ferromagnets, Giebultowica, Hill et al. demonstrated the great role of nanothermodynamics in dealing with the growth and physicochemical properties of nanosystems, Dalian Institute of Chemical The team of Zhicheng Tan at the Institute of Physics of the Chinese Academy of Sciences has also done a lot of research on the low-temperature thermal capacity of nanomaterials [6].

(4) Shape memory alloys

Lidija GOMIDZELOVIC et al. used the Muggianu model and combined it with experiments to calculate the phase diagram of the shape memory alloy Cu-Al-Zn at 293 K using Thermo-Calc software and to explore the tissue properties [7].

In addition, there are applications related to thermodynamic computer simulations in Mg-based hydrogen storage materials, graphene interfaces, and their adsorption properties.

Trends in material thermodynamics

Almost no practical material structure is thermodynamically stable, and diffusion, phase change, dislocation generation, and motion, as well as material deformation and fracture, involve various nonequilibrium, which requires combining CALPHAD model with other theories in practical applications to make it more realistic to simulate the real situation, such as: with First-Principles, density Density functional theory (DFT) and Multiphase Field VCMT Insert Method (MFM); combining with physical metallurgical models to predict hardness, strength, elongation, etc.; introducing nucleation, growth and coarsening models of cells and precipitated phases to calculate CCT, TTT phase transition curves, grain size, morphology, etc. The material properties, such as CCT and TTT phase transition curves, grain size, and nucleation rate, are calculated.

In the future, multi-scale integrated computational simulations, including thermodynamics and kinetics together with specialized databases to realize the material design phase, simulate the whole process of material production and preparation and service so as to predict the tissue evolution and macroscopic properties of materials, and precisely regulate the tissue properties during the preparation process, are the main trends in the development of materials thermal and kinetic Carbide Inserts [8,9].

References

[1] Xu Zuyao, Thermodynamics of Materials, Higher Education Press, 2009

[2] Dai Zhanhai, Lu Jintang, Kong Gang. Research progress on phase diagram calculation [J]. Journal of Materials Research, 2006, 4(20): 94-97

[3] Cui-Ping Wang, Xing-Jun Liu, Yun-Qing Ma, Ikuo Onuma, Ryo-Suke Kainuma, Kiyohito Ishida. Thermodynamic calculation of phase equilibrium of Cu-Ni-Sn ternary system[J]. Chinese Journal of Nonferrous Metals, 2005(11): 202-207.

[4] Dong Enlong, Zhu Yingguang, Pan Tao. Development of 9Ni low-temperature pressure vessel steel plate for LNG [C], Proceedings of the National Low Alloy Steel Annual Conference. Beidaihe: Chinese Society for Metals Low Alloy Steel Branch, 2008:741-749

[5] Fan Tongxiang,Zhang Congfa,Zhang Di. Advances in thermodynamics and kinetics of metal matrix composites[J]. China Materials Progress, 2010, 29(04): 23-27

[6]JYANG Jun-Ying,HUANG Zai-Yin,MI Yan,LI Yan-Fen,YUAN Ai-Qun. Current status and prospects of thermodynamics of nanomaterials[J]. Advances in Chemistry,2010,22(06):1058-1067.

[7]Lidija GOMIDZELOVIC, Emina POZEGA, Ana KOSTOV, Nikola VUKOVIC, Thermodynamics and characterization of shape memory Cu-Al-Zn Alloy [J]. Transactions of Nonferrous Metals Society of China, 2015, 25(08): 2630-2636

[8]Liux J, Takaku Y, Ohnuma I, et al. Design of Pb-free solders in electronic packing by computational thermodynamics and kinetics [J]. Journal of Materials and Metallurgy, 2005, 4(2): 122-125

[9] Chen Q, Jeppsson J, Agren J. Analytical treatment of diffusion during precipitate growth in multicomponent systems [J]. Acta Materialia, 2008, 56:1890-1896

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Contents hide 11. The contradictory characteristics of traditional uniform carbide 22. New advances in cemented carbide 33. Gradient carbide proposed 44. Properties of gradient cemented carbide 55. Gradient formation mechanism 66. Application of Gradient Cemented Carbide 77. Gradient Cemented Carbide Design1. The contradictory characteristics of traditional uniform carbideCemented carbide is a typical brittle material. The traditional uniform carbide one, the material of the various parts of the uniform composition and organization, the alloy is homogeneous throughout, its performance is consistent. The main components of cemented carbide include various hard phases and binding phases. Hard phases such as phases and solid solutions play an important role in the hardness and wear resistance of alloys. Bonding has an important influence on the strength and toughness of alloys.In general, increasing the WC grain size or increasing the Co content will increase the bond phase thickness of the alloy and improve the alloy plasticity. In alloys with good ductility, local concentrated stresses can relax the alloys with poor plasticity due to deformation. Crack initiation and propagation are induced by stress relaxation, resulting in cracking of the alloy.Therefore, the traditional method is to increase the alloy. The content and increasing the grain size serve as a direction to increase the toughness of the hard alloy. However, at the same time, the hardness and wear resistance are reduced. Conversely, hardness and wear resistance can be increased without sacrificing flexural strength and impact toughness. Therefore, there is a sharp contradiction between the hardness and toughness of cemented carbide materials, and it is not easy to obtain a conventional uniform cemented carbide with high hardness and toughness at the same time. In many service conditions, the application of traditional uniform hard alloys will have certain limitations. For example, when the rock drill ball and the cobalt head are working, they are not only subjected to impact load and torsional load, but also have to be seriously worn by the rock.This requires that the cobalt teeth not only have sufficient impact toughness but also have high The wear resistance can complete its work. When used in synthetic diamond synthesis, carbide top hammers are subjected to high temperature and high pressure, some parts are subjected to compressive stress, and some parts are subjected to tensile stress or shear stress. Different parts have requirements.Different performance and features. In this way, the conflict between the hardness and toughness of the traditional uniform structure hard alloy restricts the further expansion of its application field, it is difficult to meet the “double high” high hardness and high toughness requirements for the development of modern society, so explore The new type of hard alloy material makes it particularly important that different parts of the tool have different functional requirements.

2. New advances in cemented carbideThe materials scientists of various countries in the world are trying to solve the above-mentioned contradictions in the traditional uniform hard alloy through various effective ways, reduce production and use costs, and improve their comprehensive performance. At present, there are mainly ultra-fine and nano-hard alloys (so-called ultra-fine cemented carbide is an alloy with a tungsten carbide grain size of 0.2-0.5 μm, and nano-hard alloy is an alloy with a tungsten carbide grain size of less than 0.2 μm. ), platelet toughened carbide, coated carbide and functional gradient carbide, and other directions can effectively solve this contradiction. For example, when the cobalt content of the nano-size hard alloy is high, not only has good fracture performance, but also has a high hardness, reaching the best combination of alloy toughness and hardness functional gradient carbide by making the binder phase or hard phase along One direction is increasing or decreasing to give the different parts of the alloy different properties, so that the combination of toughness and wear resistance can be fully achieved in the use of the carbide. The following is a brief introduction to the new progress of gradient cemented carbide.Functionally Graded Cemented Carbide3. Gradient carbide proposedAbrupt changes in material composition and properties in the component often lead to significant local stress concentrations, whether the stress is internal or external. If the transition from one material to another is performed gradually, these stress concentrations will greatly increase. reduce.These considerations form the basic logical element of most functionally graded materials. Japanese scientists first proposed functionally graded materials, which are characterized by the introduction of gradual changes in the microstructure and/or composition of a component, the gradual change of its microstructure and/or composition in space, and the physical, chemical and mechanical properties of the material.The performance exhibits a corresponding gradient change in space, so that it meets different performance requirements at different locations in the component, thereby making the component as a whole achieve the best results.This design idea was introduced in the field of cemented carbide in the mid-to-late 1980s, and a gradient cemented carbide was proposed, and rapid development was quickly achieved. In the actual use of cemented carbide, different working sites often have different performance requirements. For example, the cemented carbide cobalt head requires high surface wear resistance and overall impact resistance.It is conceivable that if a new type of cemented carbide material can be developed, the structural feature of this material is that the surface layer is a structure with a low binder phase and the binder phase content of the core is an average value, between the surface layer and the core. It is a transition layer with a high binding content and a continuous distribution. In this kind of structure, due to the different distribution of bonding phase in each part, the content of the bonding layer in the alloy surface is lower than the average value in each part, with high hardness and good wear resistance, and the binding layer content in the transition layer. High, can meet good toughness and impact resistance.4. Properties of gradient cemented carbideIn the two-phase structure, the cobalt content of the surface layer is lower than the nominal cobalt content of the alloy, the cobalt content of the intermediate layer is higher than the nominal cobalt content of the alloy, and the cobalt content of the core containing the η phase is the nominal cobalt content of the alloy. As the cobalt content of the alloy shows a gradient change, the hardness of the different parts of the alloy also reflects the corresponding laws. Moreover, the gradient distribution of cobalt content makes the sintering shrinkage in different parts of the cross section non-uniform, resulting in residual stress in the alloy. Due to the low content of cobalt in the surface layer of the alloy and the high content of WC+Co+η, the surface of the alloy has very high hardness and very good wear resistance. In the middle layer of the alloy, the cobalt content is higher than the nominal content of the alloy, and thus The layer has good toughness and plasticity, so that the alloy can withstand higher loads. The η phase structure inside the alloy has good rigidity. The experimental results show that the wear resistance and toughness of DP alloy are obviously better than that of the traditional uniform hard alloy. The adoption of DP alloy can obviously improve the efficiency of rock drilling and reduce the mining cost.According to the current research status of gradient materials in various countries, there are mainly three types of gradient cemented carbide bonded phase composition carbides such as alloys, hard phase composition gradient cemented carbide (such as the β-layer used as a coating matrix. Gradient cemented carbide) and hard phase grain size gradient cemented carbide (such as grain-gradient cemented carbide top hammer).5. Gradient formation mechanismThe viewpoint of the formation mechanism of the gradient distribution of the cobalt phase caused by the directional migration of the liquid binder phase in the alloy after carburizing has not yet been unified. According to current research reports, the directional migration of liquid phase mainly includes mass migration caused by three different types of liquid phases, orientational migration of binder phase caused by different WC particle sizes, and liquid phase migration caused by different carbon content. For example, two YG alloys with the same WC carbon content, uniform particle size, and different binder cobalt content are overlapped and held at the liquid phase temperature for a certain period of time. As a result, the bound cobalt phase shifts from a high cobalt content to a low cobalt content. One side of the migration,.For example, one of different particle sizes is fine particles, and the other is coarse particles added with the same cobalt to form two kinds of mixture, and pressed into a double-layer alloy for vacuum sintering. The liquid binding phase appears to be fine from one side to the other. The grain side migrates. While the high carbon cemented carbide is decarburized in TNGG Insert the decarburizing atmosphere, the liquid binding phase will migrate from the inside to the surface of the sample, while the low carbon alloy will migrate to the center after the carburizing treatment liquid binding phase.The phenomenon of migration caused by the difference in carbon content is caused by the difference in the amount of liquid phase in the different parts of the alloy. This type of decarburized or carburized alloy has an unequal internal carbon content, and the carbon content is relatively high in regions with high carbon content. In regions with lower carbon content, the liquid phase migrates from areas with high carbon content to areas with low carbon content. Taken together, the main mechanisms of liquid phase migration are:The binder phase migrates from the coarse-grained carbide region to the fine-grained carbide region, and the driving force for the migration Tungsten Steel Inserts is the capillary pressure difference, that is, the action of the capillary force. The binding phase migrates from the high liquid phase region to the low liquid phase region and migrates. The driving force is the pressure difference in the liquid phase, that is, the role of volume expansion or contraction to generate pressure when the state of the substance in the liquid phase volume difference changes.

6. Application of Gradient Cemented CarbideGradient cemented carbide successfully solves the contradiction between hardness and toughness existing in conventional homogeneous cemented carbide. The development of this new material is considered to be the most important one in the history of cemented carbide since the 1950s. Innovation.” Due to the unique microstructure and properties of gradient cemented carbide, it has become an important research content in the field of gradient functional materials and hard alloys. Currently, it has been widely used in coating substrates, carbide cutting tools, mining and rock drilling tools, stretching dies and punching tools, and its application fields are constantly expanding.(1) Used as a coating substrateDue to the different thermal expansion coefficients of different materials, coating tool materials may crack due to thermal stress during cooling. Gradient structure cemented carbide is used as the matrix, that is, the gradient-sintered coating matrix forms a ductile region lacking cubic carbides and carbonitrides in the surface region, which can effectively prevent cracks formed in the coating from expanding into the interior of the alloy. , improve the interface bonding strength and reduce interface stress concentration, thereby improving the performance of carbide cutting tools.(2) Used as a carbide toolChange the traditional cemented carbide. The constant proportion model is used to make a graded structure hard alloy with low surface content and high core content, so that the surface layer has high hardness and good wear resistance, while the core has high strength and good impact toughness, which makes the strength and toughness of the alloy. It is well coordinated and can therefore be used to produce cutting tools with both wear resistance and toughness.(3) Mining and rock drilling tools Mining and rock drilling toolsThe use of ball teeth requires greater wear and impact during operation, which requires the alloy to have high surface wear resistance and high strength. Conventional uniform alloys are difficult to meet this requirement. Both wear resistance and toughness are significantly better than conventional uniform carbides.(4) Used as a punching toolSheet metal is usually prepared by punching or punching. With this method, the material is broken between working edges that face each other. During punching, the punch moves through the die in a direction perpendicular to the metal plate and punches the metal plate. The failure mode of the punch is usually due to the wear of the working edge and eventually leads to the cutting edge of the punch becoming conical, thereby increasing the frictional force during punching and eventually leading to a decrease in punching quality. In order to increase the life of the gradient carbide cutting tool as much as possible, a graded cemented carbide with a central η-phase region should be used, surrounded by a nucleus-free surrounding region, and with an exposed working surface of the η-phase. Using cemented carbide as the punch, the grain size of WC is 2-3μm, the number of punching times for standard cemented carbide is only 15 times, and the number of punching and shearing of cemented carbide for gradient structure is up to 64,000 times, while that of steel die punching The number is about 7231 times. It can be seen that gradient cemented carbide as a punching tool can greatly improve the service life of the tool.The study of gradient cemented carbide consists of three parts: material design, material preparation, and property evaluation. These three parts complement each other and are indispensable. Material preparation is the core of the gradient cemented carbide research. The material design provides the best composition and gradient distribution of the structure. To judge whether the designed and prepared material meets the predetermined function, performance evaluation must be performed.7. Gradient Cemented Carbide DesignGradient cemented carbide design, generally should go through the following several links First according to the structural shape of the components and the actual conditions of use, draw the thermodynamic boundary conditions from the existing material synthesis and performance database, select the possible synthesis of metal-ceramics Material combination system and preparation method Assume the combination ratio and distribution rule of the binder phase and the hard phase, and use the material microstructure mixing law to derive the equivalent physical parameters of the material structure using the thermoelastic theory and the calculation mathematics method. The distribution function of the gradient components of the material structure is simulated by temperature distribution and simulated by thermal stress, and the optimal composition distribution and material system are designed. The core work of gradient cemented carbide design consists of the following three parts:(1) Establish an appropriate gradient component distribution model so that the gradient functional material designed meets the performance requirements(2) Estimating physical properties of gradient materials(3) Calculation of temperature field and thermal stress of functionally graded materialsSee our tungsten carbide mining button bits here

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There have 2 types of coating in Carbide insert ,PVD and CVD coating .
PVD coating carbide insert mainly used for machining stainless steel and High-temperature alloy,CVD coating carbide insert mainly used for machining DCMT Insert all kinds of steel and cast iron . if you know the difference of this 2 coatings ? here ,let me share more details about it .
PVD and CVD are coating techniques. PVD stands for physical vapour deposition , CVD stands for chemical vapour deposition. The key difference between PVD and CVD is that the coating material in PVD is in solid form , in CVD it is in gaseous form. another important difference we can say that in PVD technique atoms are moving and depositing on the substrate while in CVD technique the gaseous molecules will react with the substrate.
Besides, the deposition temperatures between PVD and CVD also different , for PVD, it deposits at a relatively low temperature (around 250°C~450°C) whereas, for CVD, it deposits at relatively high temperatures in the range of 450°C to 1050°C.
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