铸件是用各种铸造方法获得的金属成型物件，即把冶炼好的液态金属，用浇注、压射、吸入或其它浇铸方法注入预先准备好的铸型中，冷却后经打磨等后续加工手段后，所得到的具有一定形状，尺寸和性能的物件。
铸件有多种分类方法：按其所用金属材料的不同，分为铸钢件、铸铁件、铸铜件、铸铝件、铸镁件、铸锌件、铸钛件等。而每类铸件又可按其化学成分或金相组织进一步分成不同的种类。如铸铁件可分为灰铸铁件、球墨铸铁件、蠕墨铸铁件、可锻铸铁件、合金铸铁件等；按铸型成型方法的不同，可以把铸件分为普通砂型铸件、金属型铸件、压铸件、离心铸件、连续浇注件、熔模铸件、陶瓷型铸件、电渣重熔铸件、双金属铸件等。其中以普通砂型铸件应用最多，约占全部铸件产量的80%。而铝、镁、锌等有色金属铸件，多是压铸件。
Castings are metal forming objects obtained by various casting methods, that is, the smelted liquid metal is injected into the pre-prepared casting mold by pouring, injection, suction or other casting methods, and after cooling, it is polished and other subsequent processing methods to obtain an object with a certain shape, size and performance.
There are many classification methods for castings: according to the different metal materials used, they are divided into steel castings, iron castings, copper castings, aluminum castings, magnesium castings, zinc castings, titanium castings, etc. Each type of casting can be further divided into different types according to its chemical composition or metallographic structure. For example, iron castings can be divided into gray iron castings, ductile iron castings, compacted graphite iron castings, malleable iron castings, alloy iron castings, etc.; According to the different casting molding methods, castings can be divided into ordinary sand castings, metal castings, die castings, centrifugal castings, continuous castings, investment castings, ceramic castings, electroslag remelting castings, bimetal castings, etc. Among them, ordinary sand castings are the most widely used, accounting for about 80% of the total casting output. Non-ferrous metal castings such as aluminum, magnesium, and zinc are mostly die castings.