Surface treatment method for metal powder injection molding pre-sintered blank

The invention belongs to the technical field of metal powder injection molding, and particularly relates to a surface treatment method for a metal powder injection molding pre-sintered blank. The method comprises the following steps of carrying out thermal degreasing on an injection-molded green body by adopting a nitrogen-negative pressure degreasing method after carrying out acid catalysis degreasing, then heating to 600 to 800 DEG C, carrying out internal carbon removal and surface reduction on the green body in a vacuum or hydrogen atmosphere, then pre-sintering the green body until a sintering neck is formed, carrying out surface treatment on the pre-sintered green body after cooling, and finally, carrying out secondary sintering to obtain the product. According to the technical scheme provided by the invention, compared with the prior art, residues in the green body are fewer, compactness is higher, most importantly, the problems of shape correction, surface deburring and the like after sintering are so