The casting is slowly heated to a specific temperature range and held for a period of time, followed by slow cooling in the furnace. This process is like letting the tense muscles gradually relax, the casting internal stress can be released, the lattice defects are reduced, the material plasticity is enhanced, the hardness is reduced, for the subsequent machining provides a good basis for machining, machining is easier to cut, the surface quality is higher. The casting is heated to above the critical temperature, kept warm and then cooled in air. Compared to annealing, normalising cools faster and gives the casting a finer grain structure. This process is like moderate exercise to make the body more energetic, can improve the strength and hardness of the casting, improve its comprehensive mechanical properties, commonly used in general structural parts with high strength requirements. Rapid heating of the castings to the critical temperature range, quickly into the water, oil and other cooling media cooling dramatically. The instantaneous huge temperature difference allows the casting internal organisation to undergo a drastic transformation, resulting in hard and brittle phases such as martensite, which significantly improves the hardness and abrasion resistance of the casting, and is suitable for parts requiring extremely high surface hardness and abrasion resistance, such as moulds and cutting tools. Immediately after quenching, the quenched castings are heated to a temperature range below the critical temperature and held. Its role is to eliminate the internal stress produced by quenching, adjust the organisational structure of martensite, reduce brittleness, improve toughness, so that the casting performance is more balanced, to avoid fracture in use due to excessive brittleness.
Then we can summarise this process as annealing, normalising, quenching and tempering. We sell all types of castings, don't worry about like grey cast iron cost is very expensive, we grey iron casting manufacturer sell grey iron castings with very awesome cost performance.