Ductile iron covers inspection: in strict accordance with test standards. 1. Appearance: No obvious casting defects, cast iron covers bearing the pattern is clear, clear handwriting. 2. Roughness test: with special mold inspection covers flatness. Making a diameter of product size, depth 37mm tire with the size of the machined from cast iron manhole cover quotes, covers on tire tool, you can not have the sound of sloshing and cast iron manhole covers, covers no more than mold, depth (37mm) with the gap at 3mm. 3. bearing loads using sampling methods. In the press do test pressure test, covers pressure 360KN 210KN confirm eligibility or batch. Gu Chang foundry specializing in the production of ductile iron manhole covers, are used in various places, welcome to buy! Theft of manhole covers methods are there? First, the chain connection method. Second, the hinge joint law. Both methods can be Manhole covers and lock into one, easy to open, that is able to use the drill rod chains, pry off the hinges. Third, only the mouth anti-spin technique method. Just reverse rotation diameter cast iron covers in place, you can open and took the covers. Gu Chang annual production of foundry cast iron covers are the best choice for business and government, not only cheap, but also to ensure product quality, trustworthy. Ductile iron manhole covers, cast iron covers Gansu, Chang-year foundry provided by Gu Chang in foundry. Gu Chang-year foundry (www.sxcnzz.com) strong, credible, in Jinzhong machining industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Chang and you work in the foundry into the brilliant, for a better future!