Automatic vacuum degassing method and device for metal powder

Abstract

The invention provides an automatic vacuum degassing method for metal powder. The automatic vacuum degassing method comprises the steps that the powder is conveyed to different sealed cabins through vibration to be heated and degassed step by step; and the vacuum degree of each cabin is monitored in real time, and the powder is automatically controlled to be conveyed to a lower-stage vibration conveying and heating platform or to be still on each platform to be heated and fully degassed according to the change of the vacuum degree. The automatic vacuum degassing effect is achieved, continuous observation of operators and manual adjustment and control are not needed, and the labor cost is saved; in addition, heating and degassing are carried out step by step in different cabins, mutual influence is avoided, and the situation that the powder is oxidized and the PPB defect in a workpiece is aggravated due to the fact that H20 and O2 react with the powder heated to the high temperature in the same cabin is avoided; h20, O2, N2, Ar and He which can be adsorbed on gaps and surfaces of powder particles are degassed step by step, so that formation of original particle boundaries (PPB) and thermally induced pores (TIP) in a workpiece is reduced, and the performance of the powder workpiece is improved.

Description

Technical field [0001] The present invention relates to the technical field of powder metallurgy, and specifically to an automatic vacuum degassing method and device for metal powder. Background technique [0002] Metal powder preparation methods mainly include argon atomization method and plasma rotating electrode method. During the preparation and storage process of the powder, a certain amount of H will be adsorbed in the gaps and surfaces of the powder particles. 2 0.O 2 ,N 2 ,Ar,He. The metastable phase structure in the rapidly cooled powder particles during hot isostatic pressing changes to a stable state. The enriched elements on the powder surface will form stable second phase particles. The oxides present on the powder surface accelerate this process. In the powder A large number of second phase particles are rapidly precipitated at the particle boundary, forming a continuous network, so that the original powder particle morphology is retained in the powder produ...

AI Technical Summary

Problems solved by technology

[0004] In the existing static degassing process, the thickness of the tray is thicker, the heating time for the powder to reach the degassing temperature is longer, the total contact area between the powder and the vacuum environment is small, and it is difficult for the adsorbed gas in the middle and lower layers of powder to penetrate the gap between the powders. In the past, the degassing effect is poor; the existing dynamic degassing technology heating body is distributed on both sides of the sealed box, because the sealed box is a high vacuum environment, there is no heat transfer medium, the temperature distribution in the sealed box is uneven, and the temperature on both sides of the box High, the middle temperature is low, which reduces the degassing effect of the powder in the middle of the box; in order to improve the degassing effect, the heating temperature in the sealed box is set higher, and the sealed box is not heated step by step for degassing, the degassed gas H 2 0, O 2 Reacting with the powder heated to a higher temperature in the same cabin will cause the powder to oxidize and aggravate the PPB defects in the part; the degassing process requires the operator to judge the powder spreading effect and vacuum degree, and adjust the powder feeding rate, which is affected by the subjective factors of the personnel , the degassing process is not stable enough

Images