The tensile, high cycles fatigue and DSC tests were made on K465 and K492 alloy. The morphology and distribution of primary carbide were investigated being used on SEM and TEM. MC-type carbide was formed as Chinese script morphology in K465 alloy. The tensile strength of as–cast K465 alloy was improved at room-temperature because of Chinese script MC-type carbide. Dispersed MC carbide was produced in as-cast K492 alloy. High-cycle fatigue strength was decreased when the size of carbide became large. High-cycle fatigue strength was increased when the size of carbide became small.