金属粉末射出成形法による４３４０合金焼結体の炭素含有量に及ぼす脱バインダ条件の影響

Abstract

Effects of debinding conditions on the carbon content and mechanical properties of sintered 4340 alloy compacts made by injection moldings were studied. Specimens were made of gas-atomized 4340 alloy powder which was blended with binders and injected into a metallic mold. The compacts were debound in air at the temperatures between 513K and 553K for 7.2ks. They were sintered in vacuum at 1623K for 7.2ks. The carbon content of sintered compacts decreased linearly with increasing in debinding temperature. This means that the carbon content of sintered compacts can be controlled accurately by the debinding temperature. In the range of debinding temperature lower than 533K, the density of sintered compacts decreased with increasing in debinding temperature, and in the range of debinding temperature higher than 533K, it became constant. The mechanical properties of sintered compacts changed with the carbon content. The higher the debinding temperature was, the lower the tensile strength of sintered compacts and the higher the elongation became.