青海西宁通风管道诚信加工厂

Bronze culture has developed in all parts of the world, because bronze has its advantages as a tool and raw www.yanglaoyuant.com.cnwww.diandongment.com.cnwww.taiyuanbanjia.com.cnwww.gonglujiemuju.cn

www.turangxiufuu.cnwww.yanglaoyuand.cnmaterial of utensils. First, there are natural pure copper blocks (that is, red copper), so copper is one of the earliest known metals. However, the hardness of red copper is low, and it is not suitable for making production tools, so it plays a small role in production. Later, tin ores were discovered and tin was extracted. On this basis, it was recognized that copper added with tin, bronze, was harder than pure copper. After testing, the hardness of red copper is 35 degrees of Brin's hardness tester, adding 5% tin, its hardness is increased to 68 degrees, adding 10% tin, that is, to 88 degrees. Moreover, the hardness can be further improved after tempering.