Submerged state premixed abrasive water jet cutting concrete impact of the main parameters of the relationship with the cutting depth

Transformation and maintenance of the project , often involving cutting of concrete structures , such as construction and mining . Currently, broken concrete cutting that traditional methods ─ ─ mechanical cutting , drawback of the method is time-consuming , laborious , inefficient and working environment pollution. With new technologies emerging cutting , water jet cutting are also numerous reports of broken concrete , but premixed abrasive water jet underwater ( in a submerged state ) cutting concrete materials research has not been reported , and the submerged state cutting technology for the transformation of flooded mine and  synthetic diamond powder  are of great significance , therefore , experimental research in the submerged state premixed abrasive water jet cutting concrete impact on the main parameters of the relationship with the cutting depth . Premixed  synthetic diamond  jet cutting concrete underwater test apparatus including premixed abrasive water jet generating system and the target object ( specimen ) mobile systems and nozzle clamping devices. Premixed abrasive jet generating system has a piston implementation stage three supercharged , the abrasive tank is placed among the high-pressure circuit , so that the abrasive and water mix to form abrasive water jet through the nozzle , the target object ( specimen ) mobile systems with DC motor driven screw drive , thyristor rectifier circuit by adjusting the output voltage to achieve speed .

High degree of accuracy and surface roughness of the mirror at the same time the requirements of a growing demand for processing

Recently, the ceramics, semiconductors, and optical glass as the representative of brittle materials have become increasingly demanding precision, especially high degree of precision and mirror surface roughness also requires processing needs are growing, this abrasive wheels is known as ultra-precision mirror finish. For the semiconductor substrate, and computer hard drives and other parts of simple geometry, usually after the first  cutting tools , polishing processing methods. But for the outer cylindrical surface and complex aspherical mirror ultra-precision machining, grinding process must also meet the high shape accuracy and small surface roughness of the dual requirements.

On the material properties put forward higher requirements, forcing the research and development of materials to a deeper and more extensive expansion direction

As we all know , energy, materials and information are the three pillar industries of China's modernization , the material is vanguard , and its development is often the precursor of major grinding wheel change and signs , while the modern requirements of the development of new materials and gave a strong impetus. In recent years, such as electronics, heat , laser, aerospace technology, automatic control , energy and information processing , and many other areas of the rapid development of emerging technologies , the performance of the material put polycrystalline diamond requirements , forcing the research and development of materials to a deeper and more broad direction of expansion. As a new special ceramics , inorganic non-metallic materials , with its unique fine structure and multi-effect , a variety of performance rapidly and widely applied in materials  synthetic diamond  of vast areas stand out, to bring the ancient ceramics new vitality. This is because the melting point and hardness of the ceramic material than metal materials generally high, with also has good insulating properties and chemical stability ( especially resistance to corrosion , oxidation resistance ) , so that it is in many high technology applications in the field increasingly extensive. Wherein the oxide ceramic high temperature oxidation due superior performance, making it easier , cheaper , it is a large number of application areas and industrial production of a high-temperature materials . 2 Literature Review Alumina is an amphoteric compounds, ionic bonding , the Department of hexagonal crystals.

Hot isostatic pressing process and its influencing factors of fracture toughness and the corresponding toughening mechanisms

Cermet is an integrated high performance hard materials, wear, corrosion and heat resistance and other fields have broad application prospects. This paper uses X-ray diffraction, scanning electron microscopy, X-ray spectroscopy, transmission electron microscopy and other experimental means of cermet sintering, hot isostatic pressing process and its influencing factors of fracture toughness and the corresponding  Abrasive grinding  mechanisms and other content a systematic study, and the fine grain Mo_2FeB_2 cermet technology for the preparation of preliminary exploration. First studied the sintering temperature, holding time, heating rate and sintering  synthetic diamond  on cermets and properties. The results showed that the sample in the liquid near the (1030 ℃ -1080 ℃) to 2 ℃ / min heating rate, by 1250 ℃ vacuum sintering 40min, to the contraction of its consistent tissue is relatively uniform, relatively good mechanical properties. Studied cermets hot  abrasive grinding  treatment process. The results show that the hot isostatic pressing treatment increases cermet hard phase particle size, particle consolidation and dissolution - precipitation mechanism is the main reason for the increase of their particle size.

To improve the mechanical properties of ceramic materials and performance

The intrinsic brittleness of ceramic materials is related to its ability to issue a widely used key issues. In order to improve the brittleness of ceramic materials to increase their  grinding wheel , scholars have proposed various countries over the years Toughening mechanisms such as particle dispersion toughening, transformation toughening, microcrack toughening and synergy toughening etc., and a variety of materials such as grain boundaries stress  cutting tools , so as to better improve the mechanical properties of ceramic materials and the use of performance, increase reliability of its work. However, current research and toughening toughening mechanism in the choice of methods and design and other aspects still need to be further expanded and deepened. As diamond allotrope of carbon one.

Diamond grinding wheel, and, also through high-temperature high-pressure sintering of polycrystalline diamond into a variety of shapes...

Diamond powder is so widely used, it not only can be directly used to produce diamond polishing paste (synthetic diamondlapping paste), diamond grinding wheel (synthetie diamond grinding wheels), but, also through high-temperature high-pressure sintering of polycrystalline diamond into a variety of shapes (synthetie polyerystalline diamonds). currently, the domestic diamond industry generally uses NIMnC. Flake catalyst  grinding wheel  compound of the JRI, JR: type low-grade diamond, after repeated grinding, pickling (ie crushing method) obtained after particle size ranging from  Abrasive grinding , such process operation cycle length, energy consumption, diamond high material loss; explosive detonation synthetic  Abrasive grinding wheel  (ie impact method) findings; while domestic cubic press on the direct synthesis of diamond powder (ie static method) for research, documentation publicly reported much. this selection of SY an I-type powder catalyst directly in the cubic press last synthesized diamond powder, and its results are analyzed and discussed.

Metal powder and diamond powder wettability of different characteristics, in order to guide the choice of metal powder system

Diamond powder compacts in the role of high-power CO2 laser sintering process . Combined with diamond powder and metal powder bonded microscopic analysis of the state introduced the metal powder and diamond powder infiltrating the different characteristics of the metal powder system to guide the selection and design . Established a  synthetic diamond  powder sintering laser power and scanning speed with the relationship between the basic framework to facilitate the process parameter selection , design and optimization. Process Study showed that: ① sintered in a non- protective  cutting tools  Ti powder compacts is more susceptible to oxidation , powder for powder wettability is poor, wear resistance is lower. ② amount of laser power increases ( amount of the scanning speed decreases ) , is conducive to the densification of sintered parts and strong carbide forming elements on the diamond powder infiltration , but if the energy of the laser input  abrasive grinding  a certain threshold will result in fine powder burning . When the spot diameter is 8.5mm , the laser power of 550W, scanning speed 1100mm/min under sintering conditions , powder sintering tool has the best performance. ③ The same process parameters , since the laser heating and compacts composition non-uniformity , surface state powder and metal binding properties and differences . For the laser sintering process in a variety of different phenomena , the sintering mechanism were studied intensively .