Flange is a kind of disc parts, the most common in the pipeline engineering, flanges are used in pairs. In pipeline engineering, flanges are mainly used for pipe connections. In the need to connect the pipeline, a variety of installation of a flange, low pressure pipe can be used to connect the flange, 4 kg or more of the use of welding flange. The gasket is added between the two flanges and then fastened by bolts. Different pressure flanges have different thicknesses and use different bolts. Company specializing in the production of a variety of materials flange flange of the production process in the first cut into the appropriate board, the length of the strip according to the size of the large flange. Then use the volume ring machine to make a circle, with the electrode welding interface firmly, at the mouth of the mouth to carry out X spectrum test. Then press the pressing, machining process and waterline, chamfering lathe, machining of bolt hole drilling is finally used to dial with the drilling machine. The cost of rolled flanges is lower than that of forging. But some of the oversized flanges are not forged. This kind of product is used to weight the weight of the theory, in the calculation, is not the waterline, rabbet, bolt hole and chamfering lose weight. Flat product prices low, but if the large flange has a dovetail groove like processing processes of the price will be higher. Theoretical weight is calculated by the following formula