May 29, 2019
Study on the mechanism of tungsten carbide leaching with cemented carbide tool
The additives in cutting fluid can promote the leaching of tungsten carbide in carbide cutting tools. Tungsten carbide leaching not only reduces the tool life, causes the waste of resources, but also causes asthma, pulmonary fibrosis and allergic dermatitis. Aimed at cutting process, carbide cutting tools in the phenomenon that the tungsten carbide leaching screening of some commonly used in water base cutting fluid and organic additives, inorganic additives they are investigated respectively the influence law of cemented carbide tungsten carbide in the leaching, leaching mechanism, and synthesis effective inhibitors prevent oxidation dissolution of tungsten carbide carbide cutting tools. The results of immersion test of cemented carbide blade in aqueous solution show that some corrosion pits appear on the surface of the blade after immersion in distilled water. When sodium carbonate solution is added, the alkalinity of aqueous solution decreases and tungsten carbide leaching on blade surface becomes more serious. The above phenomena indicate that tungsten carbide in carbide blades will oxidize to form tungsten trioxide in aqueous solution. When sodium carbonate is added, tungsten trioxide generates its own complex anion tungstate in sodium carbonate solution, which aggravates tungsten leaching due to its high ionization potential and good ability to attract ligands. In order to effectively inhibit the leaching of tungsten carbide on the surface of carbide cutter, the effects of different additives in cutting fluid on the leaching of tungsten carbide were studied.
In the production and cutting process of carbide tools, in order to protect carbide tools, cutting fluid will be used. Cutting fluid can play the role of washing, cooling, lubrication and rust prevention, reducing tool wear. However, some additives in cutting fluid will make cobalt leaching in cemented carbide and tungsten carbide oxidation dissolution and then leaching, destroy the structure of the tool material, accelerate the tool wear. The wear mechanism of triethanolamine solution, sodium carbonate solution, borax solution, benzotriethanolamine solution, oleate triethanolamine solution and oleate triethanolamine, benzotriazolazole and borax solution on cobalt and tungsten carbide in cemented carbidecutting tools was studied by immersion test and energy spectrum analysis. The results showed that borax solution, benzotriazole solution, oleate triethanolamine solution and oleate triethanolamine, benzotriazole and borax composite solution could inhibit the leaching of cobalt and tungsten carbide. At 150degrees , the cemented carbide soaked in borax solution showed no cobalt leaching, and the tungsten leaching rate was 2.88%. The mechanism of borax is as follows: the polarization reaction between the cemented carbide and the system formed by the borax solution slows down the corrosion rate of the cutting tool and inhibits the leaching of cobalt and tungsten from the cemented carbide cutting tool. At room temperature and 150degrees , benzotriazole solution has no leaching effect on cobalt in cemented carbides.
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May 23, 2019
Carbide wire drawing dies can be extended by nitrogen ion implantation
In the production of carbide wire drawing dies, some special cavity processing is often encountered. For example, the processing of the hard alloy flat wire drawing die for the lining material of the chain production industry requires very high requirements on the thickness and width of the clockwork, so the manufacturing of the die cannot be solved with the general alloy material, and the processing of the ideal mold material and the hard alloy blind cavity is always a thorny problem.
Ion implantation originated in the 1960s and 1970s and was first applied to the doping of semiconductor materials. The surface modification of non - semiconductor materials began after 1970 s. Nitrogen ion implantation materials easy, simple process, so the rapid development. At present, the main development direction of ion implantation is to develop high energy and large beam ion implantation and multi-direction ion implantation, and popularize its application in production. PCB is one of the basic products in the electronic industry and microhole machining is an important process in PCB processing. Its processing quality directly affects the quality and precision of the printed board. At present, the commonly used PCB bit is made of hard alloy, and its drilling quality and precision have been greatly improved than before, but still can not keep up with the PCB industry to high precision, high density direction of development speed. Therefore, it is an urgent task to seek alternative products for drill bits or to reinforce existing ones. Because cemented carbide is a kind of tool material with excellent properties, it is difficult to improve its cutting performance effectively by general plating, coating and other strengthening methods. Ion implantation is very effective in strengthening and modifying the surface of materials. This research group, together with the Beijing PCB association and related professional board manufacturers, conducted a re-strengthening test of the PCB bit with nitrogen ion implantation method, and achieved obvious results.
Ion implantation process, began to develop semiconductor devices, only in the early 1970s for the surface treatment of metal materials, to improve the surface hardness, wear resistance, fatigue and corrosion resistance. At first, ion implantation was used to process various molds, cutting tools, medical scalpels, gears, bearings, oil injectors, etc., and good results were obtained. After the basic research of ion implantation samples in the laboratory, the drawing die made of tungsten carbide base hard alloy was selected to conduct a comparative test on the production site after nitrogen ion implantation. 1. For the nitrogen ion implantation of the drawn troclet, the small drawing die and carbide wire drawing dies with large deformation for the semi-finished copper wire were selected for the test. The chemical composition of the drawing die material, steel wire die and copper wire die YGSYG3, had poor stability.
Therefore, from the operation process to take f two measures
(1) will be fixed in the target room on the fixture of the mold, every 5 minutes once a 90 Angle, so that the mold hole diameter parts of the working surface can be more evenly injected nitrogen.
(2) with manual control to choose the appropriate ion beam and die hole between the center line of the incident Angle, generally not more than 30. Thus, the injection time is only 30 minutes. Ion implantation depth is generally very shallow, about 10~100 atomic layer, in the same process conditions, hard alloy ions.
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