Just formed castings, the internal microstructure is chaotic, the atomic arrangement is disordered, just like the unorganised bookshelf, all kinds of books randomly stacked. This uneven structure makes the casting internal stress. The existence of internal stress as a hidden danger, will reduce the dimensional stability of the casting, so that it is easy to deform or use in subsequent processing or even cracking, seriously affecting the quality of the casting. Heat treatment can rearrange the internal atomic arrangement, eliminate internal stress, optimise the organisational structure.
Not all castings need heat treatment. Some of the performance requirements are not high, the shape is simple and the use of mild castings, may not be heat treatment. For example, some decorative castings, only to meet the appearance and basic strength requirements. Castings of different materials due to the chemical composition and organisational structure of different, applicable heat treatment process varies greatly. Cast iron with high carbon content, annealing is often used graphite annealing; cast steel according to the content of alloying elements to choose a different quenching temperature and cooling medium; aluminium alloy has a solution treatment and aging treatment and other unique processes. In the heat treatment process, temperature control is the core. Too high a temperature may lead to overheating and overcooking of the castings, making the grains coarse or even melting; too low a temperature will not achieve the desired treatment effect. Just like cooking fire mastery is not good, dishes either burnt or not cooked, must be strictly in accordance with the material properties and process requirements for precise control of heating and cooling temperature.
Heat treatment can improve the performance of castings through the carefully designed combination of 'heating - holding - cooling'. As hydraulic casting supplier, some of our hydraulic casting, pump castings and other castings will be heat treated, so that good quality castings.