What does D400 heavy-duty ductile iron manhole cover mean?
2 Answers
D400 heavy-duty ductile iron manhole cover refers to a ductile iron manhole cover with a load-bearing capacity of 40 tons. Below is an introduction about automobiles: 1. Definition: According to the latest national standard "Terms and Definitions of Motor Vehicles and Trailers" (GB/T3730.1-2001) in China, an automobile is defined as a non-track vehicle powered by an engine, with four or more wheels. 2. Function: Mainly used for transporting people and/or goods; towing vehicles carrying people and/or goods; and for special purposes. 3. Regulations: Starting from July 1, 2018, China reduced import tariffs on complete vehicles and auto parts.
Having driven for decades, I've lost count of the manhole covers I've seen. This D400 heavy-duty ductile iron manhole cover is, frankly speaking, the tough stuff designed specifically for heavy vehicles on highways. D400 represents its load-bearing capacity, capable of withstanding approximately 400 kilonewtons of force, which translates to enduring a 40-ton truck rolling over without deformation or cracking. I'm familiar with ductile iron—it's commonly used in automotive engine components due to its heat resistance and impact toughness, unlike regular iron sheets that shatter upon impact. Poor-quality manhole covers on roads can cause wheel slippage or tire blowouts when vehicles pass over them, making drivers suffer. Once on the highway, I encountered a loose manhole cover that caused severe jolts, but thankfully, nothing serious happened. Regularly inspecting these facilities is as crucial as maintaining your beloved car—it ensures smoother and safer driving.
