Technical Standards for Ductile Iron Manhole Covers

Wholesale of ductile iron manhole covers: Specifications of ductile iron manhole covers: The specifications of ductile iron manhole covers and gray cast iron manhole covers are the same, but the materials are different. Let me introduce you to "Chemical and physical characteristics of new ductile iron manhole covers using QT500-7 cast ductile graphite Cast iron is light in weight, high in strength, good in toughness, anti-corrosion, fatigue-resistant, and suitable in cost. Compared with gray cast iron manhole covers of the same specification and size, it is 40%~50% lighter in weight and 40%~50% stronger than old gray cast iron manhole covers. The old gray cast iron manhole covers are very brittle and easy to break. Now compare the chemical composition and physical properties of ductile iron and gray cast iron products. From the comparison of the above chemical composition and physical property data, it can be concluded that ductile iron has several material decisive indicators in terms of tensile strength, elongation, yield strength and ultimate load pressure head. All are much higher than gray cast iron, and its chemical composition data are much more reasonable than gray cast iron.

1. Anti-theft device

In terms of anti-theft, the new nodular cast iron anti-theft manhole cover adopts the form of a hidden latch (this achievement has been applied for and obtained a national patent). The hidden latch is connected by a fixing hole, a spring shaft and a thrust fixing card. There is no need for a handle lock to withdraw from the extraction cover, and it can be locked automatically. It is simple, firm and reliable; the old-style gray cast iron manhole cover must be embedded with iron parts before the construction of the drainage well, and then an iron chain should be installed before the manhole cover is dredged. It is easy to operate, and the embedded iron parts and iron chains are easy to disconnect, and it is easy to cut artificially to lose the anti-theft function.

2. Lifting device

Due to road maintenance, raising the road surface and other reasons, the manhole cover will be lower than the road surface. To make it flush with the road surface, the entire manhole cover base must be dug, which is time-consuming and labor-intensive. In addition, when building, expanding, and rebuilding asphalt pavement, when various manhole covers on the road are to be raised, it is necessary to re-excavate relatively large wells to raise the manhole cover after the pavement is paved, resulting in great public opinion on the secondary excavation of the road surface. In order to avoid secondary excavation and reduce the impact on citizens' work and life, the new ductile iron anti-theft manhole cover can solve this problem. That is, by superimposing the outer frame to make the manhole cover flush with the road surface, it is not necessary to dig the entire manhole cover base during installation, saving 70% of the man-hour.

3. Anti-shock noise device

The new nodular cast iron anti-theft manhole cover increases the matching depth between the frame and the cover by padding polychloride ether pads on the joint surface of the frame and cover. The six-point contact is used to make the cover frame fit tightly and the hinge is used together. Tightening bolts and anti-theft locks basically eliminate noise and reduce vibration, which basically eliminates the common noise problems of old gray cast iron manhole covers when they are hit by cars and the phenomenon that they are taken away by car shocks.

Fourth, the repeated use value is not high

The old gray cast iron manhole covers contain high cast iron content and are of high value when remelted. They are often frequented by thieves. A complete manhole cover is broken into pieces and sold to private buying stations. The government suffers huge losses. The new nodular cast iron anti-theft manhole cover is made of several materials and contains impurities. The value of multiple recycling processing and reuse is not high. This is the fundamental way to effectively prevent thieves from stealing.

5. Beautiful appearance

The material used for the new ductile iron anti-theft manhole cover is high-quality nodular iron pig iron, coke and special nodularizer from a designated production plant. The nodularization level is controlled within the range of level 1~2. Under the premise of ensuring the flatness of the exposed surface, the manhole cover is integrated into the road surface and the road to become an integration to achieve the effect of beautifying the city. However, the old gray cast iron manhole cover has a dark gray color and a rough appearance. The concrete well ring must be exposed. The color of the asphalt surface layer is inconsistent with the asphalt surface layer.

Ductile iron manhole cover is a kind of ductile iron products. Nodular cast iron obtains nodular graphite through spheroidization and inoculation treatment, which effectively improves the mechanical properties of cast iron, especially improves plasticity and toughness, so as to obtain higher strength than carbon steel. Ductile iron is a high-strength cast iron material developed in the 1950s. Its comprehensive performance is close to that of steel. It is based on its excellent performance that it has been successfully used to cast some complex stress, strength, toughness and wear resistance. More demanding parts. Ductile iron has rapidly developed into a cast iron material that is second only to gray cast iron and is widely used. The so-called "substituting iron for steel" mainly refers to ductile iron.