The salt core is made by middle-temperature sintering, with high quality mine salt (high sodium chloride content) and inorganic binder(high temperature durable ) with the right amount of cosolvent. Pressing salt into the figure, middle-temperature sintering , then with fine processing. Our salt core has advantages in uniform dense, exact size and suitable settings in the piston models. The salt core is easy to flush and solve, without any solid particles. the salt core is washed with water to dissolve to form a smooth gallery. The soluble salt core method is the most advanced one for forming inner cooling gallery in the world today. The process of producing inner cooling gallery piston with salt core technology uses soluble salt cores by special processing, that is, the mold salt cores with special shape, sufficient strength and smooth surface.