Casting historic application. Ancient people used to make castings and some life appliances. In modern times, mainly used for rough casting machine parts, precision castings, and some can also be used directly as machine parts. Casting mechanical products occupy a large proportion, such as tractors, the casting weight of about 50 to 70% by weight of the machine, agricultural machinery accounted for 40 to 70 percent, machine tools, internal combustion engines, such as the 70 to 90%. All kinds of castings, casting machinery used in the most varieties, the most complex shapes, the amount also covers mold largest, accounting for about 60% of the total production of castings. Followed by the ingot mold and metallurgical engineering pipeline, as well as some of the tools of life. Casting is also closely related to daily life. For example, often use the door handles, locks, radiators, down the water pipes, pots, gas hob, iron, etc., are casting. Classification mainly sand casting foundry and specialty casting two categories. An ordinary sand casting, the use of sand as the mold material, also known as sand casting 700 covers, foundry, including wet sand, dry sand and chemical hardening sand three categories, but not all can be used for sand casting. Benefits are lower cost, because the mold used sand can be reused; drawback is time-consuming mold making, casting itself can not be reused covers size, damage can be achieved after shave products. 1.1 Sand (core) casting methods: wet sand type, self-hardening resin sand, water glass sand, dry-type and dry type, solid casting, vacuum molding. 1.2 sand core manufacturing method: is selected based on the sand core size, shape, production volume and the specific production conditions. In production, a whole can be divided into handmade and machine-made core core. Two special casting, press molding material can be divided into natural mineral sand as the main form of special casting material (such as investment casting, mud casting, shell casting, vacuum casting, solid casting, casting ceramics, etc.) and metal as the main material of special casting mold (such as metal casting, pressure casting, continuous casting, low pressure casting, centrifugal casting, etc.) categories. Cast iron manhole covers | covers | Chen Hua Chen machinery provided by the China Machinery Equipment Co., Ltd. Qingdao. Qingdao Hua Chen Machinery Co., Ltd. (www.qdchenhua.com) strong, credible, in Qingdao, Shandong CNC machine tool industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Chen Hua machinery and you hand into the brilliant, for a better future!