Chemical analysis, tencile test, carbon & sulfur analysis, loading test. All of those are aim to ensure cast iron manhole cover and gully grate`s quality.
As we know, the manhole covers and gully grates loading class from A15 to F900, it means the manhole cover can bear 900KN pressure.
when we test manhole cover, the test machine will give it a pressure as much as 900KN. If it keeps perfect, the product is OK, if not, we will recast it.