Hello, this is according to the theoretical weight of the flange. For example, the theoretical weight of 1.0MPA flange in DN 100 in the 8 1-94 standard of the Ministry of Machinery is 4.0 1. If one kilogram is sold in 9 yuan, it will be 4.0 1X9. And some flanges without theoretical weight can be calculated by formula. You can enter "big flange" in the entry on Baidu. There is a calculation method on it.
Generally refers to the theoretical weight of the finished product.
I am Hebei Wanrun Pipe Industry Co., Ltd. Our company specializes in producing flanges, elbows and heads. My name is Zhu. I am from Mengcun, Cangzhou, Hebei. I hope my answer can help you.