鉄鋼の浸燐および浸燐浸炭について

抄録

Phosphorizing of steels was studied by utilizing the treatment in ferro-phosphorous grains or in molten salts containing NaPO₃ at various temperatures. Some properties of phosphorized steels were also examined. The results were summarized as follows:
1. When steels were treated in ferro-phosphorous grains containing several percent of charcoal at about 1000°C, the phosphorized layer was uniform and smooth. In molten salts containing NaPO₃, the specimen of steel was corroded and the phosphorized layer was porous. However, if the molten salts containing not only NaPO₃ but also several percent of NaCN, a uniform phosphorized layer was obtained.
2. The phosphorized steel was rapidly attacked by chemical corrosion in acidic solutions, but showed excellent resistant to weathering.
3. Phospho-carburizing in molten salts containing NaPO₃ and about 15% of NaCN was studied. Martensite in phospho-carburized and quenched specimens was harder than iron-carbon martensite in usual carburized steel. The hardness of P-C martensite reached to about Hv 1000.