| 摘要 |
PURPOSE: To impart superior corrosion resistance to gastric juice and a liq. disinfectant-sterilizer by controlling the porosity of a stainless steel sintered material and limiting the Cr, Ni and Mn contents of the compsn. and the grain size. CONSTITUTION: Metal powder is sintered so that pores in the resultant sintered parts are formed as closed pores and the porosity is regulated to <=7vol.%. By this method, corrosion resistance comparable to that of a material produced by melting can be ensured, but almost perfect corrosion resistance is preferably imparted by attaining <=5%, especially <=3% porosity. The C, Cr and Ni + Mn contents of the compsn. of the sintered parts are regulated to 1.2wt.%, 10-25wt.% and 0.5-27.0wt.%, respectively, and the grain size is regulated to <=200μm. The surface of each of the sintered parts is coated with a dense chromium oxide film, the corrosion resistance is improved and grain boundary corrosion can be prevented.
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