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SynopsisMachinability of 304L sintered steel is quantitatively assessed by means of drilling and turning tests. Generally, the sintered steels have more or less residual pores in the matrix, different from wrought alloys which are regarded as of almost full density, and the cutting resistance for the former is evidently influenced by the density.It is found that the cutting resistance has the minimum value in the density of approximately 7g/cm' in drilling test of AISI304L sintered steel prepared under various pressing and sintering conditions.In machining sintered steels, shape and density of chips usually varies with density of the given matrix.It is confirmed in this study that the cutting resistance increases in proportion to AD-ID,-DI, where DS, D~ are the density of a sintered steel and that of cutting chips, respectively.For S-bearing 304L type sintered steels, cutting resistance decreases monotonically with increasing the amount of S-addition up to 0.4 %, and also tool life is markedly improved compared to that S -free sintered steel, although tool life of sintered steel is unexpectedly shorter than that of wrought alloy.As a structural feature of S-added sintered steels, it is confirmed by means of X-ray diffraction analysis that there are sulfides present in the form of CrS in the matrix probably because Mn-content in steel is intentionally lowered from the viewpoint of powder metallurgical process.

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