Gu Chang-year foundry cast iron manhole covers with you why are generally circular? The reason for using a circular cast iron covers can reverse thrust out from the negative point of the square cast iron covers. If square, because it is significantly longer than the diagonal of the square each side, when the covers are rolled so on, it is easy to fall into the wells diagonally wellhead, causing a safety hazard. If the wellhead or significantly less than the covers made of round, square manhole cover will not fall into the well. Wellhead wellhead use depends on the size, If you have to install an area much larger than the above wellhead square manhole cover, then the use of natural materials and practical value does not directly use the circular covers more efficient, but to make cast iron manhole cover price increases . Gu Chang-year foundry mainly produces all kinds of manhole covers. Welcome to buy! Each cast iron covers the art heat treatment operations are in the solid state by heating range, three-step process consisting of insulation and cooling. Because different Taigu price covers the heating temperature, holding time and cooling rate, the matrix structure is also different Taigu obtained Which covers, so Taigu wholesale covers, cast iron production in addition to appropriate adjustments in order to control the chemical composition of the matrix organization altogether In addition, heat treatment is to control and improve the way a change to be the tomb of the body tissue to improve the performance of cast iron. Shanxi Taigu County Chang foundry is located in the hometown Inoue - Kim Gu treasure. Taigu Shanxi Jinzhong City, State Road 108, Hu Taigu Village Industrial Park covers malleable, east long high-speed, high-speed north Tongyu Qi convenient transportation and accessible. Taigu covers custom, Chang-year foundry (certified), covers by Gu Gu Chang in foundry. Gu Chang-year foundry (www.sxcnzz.com) is Jinzhong, machining leader, over the years, the company is implementing the scientific management, innovation and development, the principle of honesty and trustworthiness, and satisfy customer needs. Chang-year leadership in the foundry staff warmly welcome all inquiries negotiations to create Chang foundry in a better future.