Ductile iron manhole cover: gray cast iron manhole covers and milling of cast iron manhole covers manufacturers compared to the carrying capacity to improve the toughness of the material is relatively difficult to improve rust, mainly used in the main driveway and major road Cheng, however, a substantial increase in price, too, because Its value has recovered stolen easily stolen in order to solve problems, develop a lot of cast iron manhole cover locking milling of cast iron manhole covers, to some extent, although security issues has improved, but then sometimes someone will steal supply milling of cast iron manhole cover smashed covers, or because the key lock is used in the production of universal milling of cast iron manhole covers, and often can not prevent theft by locking the professional rust and affect the cost and open up further, giving users a difficult economic and usage. milling of cast iron manhole covers as part of the city roads municipal facilities, people living and working closely with ductile iron manhole covers chemical and physical characteristics of the use of cast ductile iron QT500-7, light weight, high strength, good toughness, corrosion resistance, fatigue resistance, cost appropriate, with the same Size compared to gray cast iron manhole covers, 40% to 50% lighter weight, higher strength compared to 40% to 50% higher than the old gray cast iron manhole covers. The old gray cast iron manhole covers brittle, easily broken. Now ductile iron and gray cast iron chemical composition of products to enhance corporate management is still an important task of the industry. Industry to actively guide companies to manage their own concerns, the industry should guide the quality of their importance to the development of industry production characteristics shown by the unbalanced nature of the decision on their own stalls should not be too large. Ductile iron manhole covers manufacturers _ Shandong Ductile iron casting provided by the Yangtze River Yangtze _ casting. If you have any questions about this information or consultation, please contact us now! Our company name: Changyi City, Shandong Province, Changjiang foundry (www.changjiangzhuzao.com) Contact: Zhang, or click on "Commercial Union Service" direct dialogue with us!