Preparation method of free-fall two-stage powder-mixing gas-atomized water-cooled fast-setting magnetic abrasive

Abstract

A free-fall two-stage powder-mixing gas atomization water-cooled quick-setting magnetic abrasive preparation method is characterized in that: a two-stage free-fall nozzle is used, the first-stage nozzle is a low-pressure powder-mixing jet nozzle, and the second-stage nozzle is a high-pressure air flow nozzle. The low-pressure powder mixing jet nozzle is close to the top of the high-pressure air flow nozzle; by adjusting the water level of the cooling water in the atomization cooling chamber, the cooling speed of the mixed powder metal droplets is controlled, thereby forming a hard abrasive on the surface of the magnetic abrasive metal matrix. Distributed magnetic abrasives. The method solves the problems of full mixing of hard abrasives and molten metal liquid before atomization and waste of hard abrasives, control of the proportion of hard abrasives in magnetic abrasives, erosion wear of single-stage nozzles, hard abrasives in magnetic abrasives, etc. Problems such as the control of the depth of the superficial layer of the metal substrate, and at the same time greatly reduce the flying distance of the powder-mixed metal droplets, and reduce the overall height of the atomization chamber and equipment. The invention provides a new technical method for the preparation of high-performance magnetic abrasives.

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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