Large flanges refer to flanges that exceed the size specified by the relevant state departments. Generally refers to flanges above DN2000. The largest size among the national flange standards GB/T9119-2000 is DN2000. The production of such flanges must be produced by the construction party providing drawings.
There are two production processes: forging and rolling. The cost of rolled flanges is lower than forged flanges. But some oversized flanges cannot be forged. Most of these products are weighed by theoretical weight. In the calculation, the weight of waterline, spigot, bolt hole, and chamfer is not reduced. The theoretical weight is calculated according to the following formula. The materials are stainless steel, carbon steel and alloy steel. Products over 3 meters should pay attention to the transportation matters when signing the contract. The height limit for highways or general viaducts is 4.5 meters. The flange itself is 3 meters in diameter, and the height of the truck itself is about 1.5 meters, and it will not pass. If it is transported horizontally, the large flange of 3M will also exceed the width of the carriageway, so whether it is transported vertically or horizontally is a problem. If the delivery problem is not solved well, it will cause certain difficulties in transportation.
