Process method for adjusting size through isostatic pressing pressure

Abstract

The invention discloses a process method for adjusting the size through isostatic pressing pressure, which is used for forming compacts in the field of neodymium iron boron manufacturing, the size change in each direction meets the design requirement, and the process method comprises the following steps of: selecting the same batch of neodymium iron boron powder and putting the neodymium iron boron powder into the same mold for forming compacts; putting the molded pressed blank into the same isostatic press for pressing; sintering the molded pressed blank subjected to isostatic pressing; recording the size change of the sintered molded compact; repeating the steps for many times, wherein the pressures of the isostatic pressing repeated each time are different; and comparing the size changes of the sintered molded compact after different isostatic pressing pressures, and finding out a change rule. According to the process method disclosed by the invention, a batch of powder is selectedto test the pressure of the same specification in the same mold, isostatic pressing is carried out by using different pressures respectively, the sizes of the sintered blank in all directions under different isostatic pressing pressures are measured, and a size change rule can be found out.

Description

technical field [0001] The present invention relates to the dimension change in each direction of a formed compact in the field of NdFeB manufacturing, in particular to a method of adjusting the size of the isostatic pressure to make the dimension of each direction of the final sintered compact meet the design tolerance requirements. Background technique [0002] In the NdFeB manufacturing process, the process steps from powder to sintered billet are: forming (compact) - isostatic pressing (compact) - sintering (sintering). At present, the method adopted by the NdFeB industry is as follows: first test the powder for a few pieces, then press the green compact with a fixed isostatic pressure, and finally put it into the furnace for sintering. In accordance with the design size, the mold parameters are adjusted, and finally the tolerance range of the sintering design is reached before batch molding. The problem existing in the prior art is that the NdFeB powder is affected by ...

AI Technical Summary

Problems solved by technology

The problem existing in the prior art is that the NdFeB powder is affected by particle size and oxidation, resulting in a deviation in the size shrinkage ratio between different can powders produced by the same formula, and it is necessary to modify the mold parameters to reach the design size of the sintered billet. The disadvantages are: 1. The cost of mold making and modification increases; 2. It takes a long time to modify the mold, resulting in a long delivery period; 3. During the modification of mold parameters, NdFeB powder forms a backlog of manufacturing funds

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