| 摘要 |
PURPOSE: To provide a process for producing a sintered hard alloy which has wear resistance and is used for warm or hot working tools having excellent fracture toughness and oxidation resistance and a composite sintered hard allay roll formed by using the sintered hard allay as an outside layer material. CONSTITUTION: This sintered hard allay is basically prepd. by compounding Cr-Si compd. powder with raw material powder of the sintered hard alloy consisting of a hard phase of WC and a bond phase of Co and Ni and sintering a powder mixture contg., by volume, 15 to 25% Co powder, 5 to 15% Ni powder, 0.5 to 10% Cr-Si compd. powder and 50 to 79.5% WC powder. The Cr-Si compd. is any one kind among Cr3 Si, CrSi, CrSi2 or a mixture composed of >=2 kinds thereof. The average particle size of the WC powder is specified to 1.0 to 10μm. Sintering is executed in a reduced pressure atmosphere of 1350 to 1450 deg.C after press molding of the powder mixture or is executed by packing the powder mixture into a vessel for a hot isotropic pressurization treatment, then subjecting the inside of the vessel to a deaeration treatment, hermetically sealing the vessel and subjecting the powder mixture to the hot isotropic pressurization treatment under atmosphere conditions of 1200 to 1400 deg.C and a pressure of <=150MPa.
|
