2results about How to "Reduce sintering deformation" patented technology

This invention discloses a method and rapid verification device for improving the one-time molding rate of large-size NdFeB products. The method includes: taking a selected amount of alloy powder, simulating the formal molding process in the rapid verification device, acquiring pressure-displacement data in real time during the molding process, and plotting a pressure-displacement curve; comparing the pressure-displacement curves of alloy powders with different powder state parameters when reaching the same compaction density, and selecting the powder state parameter with the most stable curve shape and the required molding pressure to reach that compaction density within a preset optimal range as the optimal powder state parameter; based on the optimal powder state parameter, producing large-size NdFeB green blanks in a formal production mold. This invention can efficiently screen out the optimal powder state parameters required for molding before inputting into the formal mold, significantly shortening the molding press debugging cycle, reducing trial and error costs, and significantly improving the one-time molding rate of large-size NdFeB products.

The invention provides an F75 stainless steel special-shaped part and a sintering method thereof, and belongs to the technical field of material processing.The sintering method comprises the following steps that a blank is placed in a sintering furnace, and a binder in the blank is removed through nitrogen gas flow introduced into the sintering furnace, so that the carbon content in the blank is smaller than or equal to 0.2%, and the oxygen content in the blank is smaller than or equal to 0.1%; argon is introduced when the degreased blank is in a sintering neck forming stage, a grain boundary growth stage and a pore spheroidizing stage, and stepped heating adjustment, heat preservation time adjustment and argon flow control are conducted on a sintering furnace according to different stages of the degreased blank in sequence, so that a primary sintered blank with the density larger than or equal to 7.5 g / cm < 3 > is obtained; and the sintering furnace is cooled, argon continues to be introduced into the sintering furnace, it is ensured that the internal phase body of the structure of the primary sintering blank is changed, and the sintering blank is obtained. By means of the method, the problems that in the prior art, a prepared F75 stainless steel special-shaped part is serious in deformation and unstable in size can be solved.