射出成形した高速度鋼SKH53の焼結挙動と機械的性質

概要

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Sintering behavior and mechanical properties of the injection molded SKH53 high speed steel were investigated. Water atomized fine powder mixed with organic binder was molded by injection into transverse rupture specimen. After thermal debinding, specimens were sintered in vacuum at the temperatures between 1215 and 1246°C for 1 hour. On the sintered specimens, transverse rupture strength was estimated and microstructures were examined in detail.<BR>The debound specimen exhibited very rapid densification at the tempreature between 1220 and 1225°C, which is characteristic to liquid phase sintering. Above 1225°C, nearly full density was attained and the specimens showed high transverse rupture strength more than 200kg/mm2. When the sintering temperature of 1240°C was exceeded, however, transverse rupture strength sharply decreased with the formation of continuous grain boundary carbides.<BR>For the binder and the debirding method used in this study, the amount of carbon picked up from binder was inferred about 0.17wt% from the chemical analyses of the powder and the sintered specimen.<BR>In conclusion, excellent mechanical properties can be obtained by applying powder injection molding to SKH53 high speed steel if sintering temperature is strictly controlled. But pick-up of carbon from binder should be taken into consideration to control carbon content of sintered parts.
社団法人粉体粉末冶金協会の論文