Sinter-forging process was studied for the production of sintered $YBa_2Cu_3O_x$ superconductor having high Jc. And the effect of applied uniaxial stress, temperature, and sinter-forging time on the sintering behavior, microstructural variation, and Jc have been studied. Also, powder was prepared by spray-roasting with feed solution of nitrates in order to eliminate the source of carbon which is harmful to Jc. Spray-roasting powder was calcined more rapidly than the mixture of $Y_2O_3$, $BaCO_3$, and CuO powders. It is observed that the application of relatively small uniaxial stress (2MPa) produced increase in the sintered density by 15% compared with pressureless sintering. The shear deformation and sintered density increase with temperature, an enhancement of grain alignment was accompanied. Liquid phase was formed at 900°C and the presence of liquid phase largely enhanced densification and grain alignment. The transport critical current densities (Jc) of sinter-forged $YBa_2Cu_3O_x$ superconductors were between 360-420 A/$cm^2$. These Jc values were much higher than that of pressureless sintered specimens which were made of powders prepared by solid state reaction. It can be suggested the spray-roasting and sinter-forging were effective to increase Jc of $YBa_2Cu_3O_x$ superconductors. It is well known that liquid phase was harmful to Jc. However, Jc of samples sinter-forged at 90°C were higher than that of 880°C in spite of the presence of liquid phase. It is supposed that the Jc increasing effect of grain alignment overwhelmed the Jc lowering effect of liquid phase.
