Free-falling double-stage powder mixing gas atomizing water-cooling fast-setting magnetic abrasive preparing method

Abstract

The invention provides a free-falling double-stage powder mixing gas atomizing water-cooling fast-setting magnetic abrasive preparing method. The method is characterized in that double-stage free-falling nozzles are adopted, the first-stage nozzle is a low-pressure mixed powder flow jetting nozzle, the second-stage nozzle is a high-pressure gas flow nozzle, the low-pressure mixed powder flow jetting nozzle is next to the portion above the high-pressure gas flow nozzle, and by adjusting the height of the water level of cooling water in an atomizing and cooling chamber, the cooling speed of powder mixed molten metal drops is controlled, so that the hard abrasive forms the magnetic abrasive distributed on a surface shallow layer of a magnetic abrasive metal matrix. According to the method, the effect of fully mixing the hard abrasive and molten metal before atomization is achieved, waste of the hard abrasive is avoided, the proportion of the hard abrasive in the magnetic abrasive is controlled, erosive wear to a single-stage nozzle is avoided, and control over the depth of distribution of the hard abrasive on the surface shallow layer of the magnetic abrasive metal matrix is achieved; meanwhile, the flight distance of the powder mixed molten metal drops is shortened substantially, and the overall height of the atomizing chamber and equipment is reduced. The method is a new technical method for preparing the high-performance magnetic abrasive.

Description

technical field [0001] The invention provides a method for preparing a free-fall two-stage powder mixing gas atomization water-cooled fast-setting magnetic abrasive, which belongs to the technical field of magnetic abrasive material preparation. Background technique [0002] High-efficiency ultra-finishing machining technology is a long-term priority research field funded and encouraged by the state, and the new automatic machining theory and technology for ultra-smooth free-form surfaces is a hot spot that manufacturers and researchers all over the world pay attention to. The processing quality of ultra-smooth free-form surface is an important symbol to measure a country's manufacturing technology level, and it is of great significance to ensure the development of the country's cutting-edge industries and certain high-tech industries. In recent decades, with the rapid development of computer technology and modern control theory and other related technologies, flexible proce...

AI Technical Summary

Problems solved by technology

[0018] At present, the main problems of magnetic grinding and finishing are the low service life of magnetic abrasives, poor metal cutting ability, difficult preparation and high cost.

[0019] (1) Jet nozzle problem: due to the use of a single nozzle, the jet velocity of the gas-solid two-phase flow is high, resulting in rapid erosion and wear of the jet nozzle, and it fails in a very short time, and the preparation function of the magnetic abrasive is lost; at the same time, it is also due to the A single nozzle is used, and the hard abrasive and high-pressure gas are used as the atomizing medium. If the jet velocity of the gas-solid two-phase flow is low, the atomization effect will be poor and the magnetic abrasive particles will be coarse. However, if the jet velocity of the gas-solid two-phase flow is high, although the magnetic Although the particle size of the abrasive is reduced, the hard abrasive will splash out again after entering the molten metal, resulting in a sharp decrease in the hard abrasive contained in the magnetic abrasive metal matrix, and the grinding performance of the magnetic abrasive is significantly reduced;

[0020] (2) Condensation rate control of liquid magnetic abrasive droplets: Since the problem of accurate control of condensation rate of molten magnetic abrasive droplets has not been solved, the depth distribution of hard abrasives in the metal matrix of the prepared magnetic abrasives has not been stable enough, directly Affect the grinding ability of magnetic abrasives, and the scrap rate is high;

[0021] (3) The content control of hard abrasives in magnetic abrasives: due to the difficulty of accurately controlling the flow rate of hard abrasives in gas-solid two-phase flow in the pneumatic powder mixing device, the content of hard abrasives in magnetic abrasives is unstable and the magnetic abrasives Unstable performance;

[0022] (4) Erosion and wear of the molten metal guide tube: the tightly coupled atomization method is adopted. Before atomizing the molten metal flow, the gas-solid two-phase flow is first sprayed onto the lower end of the molten metal guide tube, causing The lower end of the molten metal diversion pipe has serious erosion and wear in a short period of time, which leads to the risk of back spraying of molten metal and high-pressure gas along the molten metal diversion pipe

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