大口径法可采用各种标准法兰和非标准法兰。这些都是根据客户的需要的法兰型号和材质，通常市面上采用比较多的是国标法兰。大口径法兰的公称通径以DN表示，钢管的外径以D来表示。国标法兰的外径也以D表示，螺栓孔中心圆以k表示，螺栓孔数以n来表示，密封面以d，f，法兰的厚度是c,大口径法兰的内径以b表示。
All kinds of standard flange and non-standard flange can be used for large diameter method. These are flange models and materials according to the needs of customers. Generally, more national standard flanges are used on the market. The nominal diameter of large-diameter flange is represented by DN, and the outer diameter of steel pipe is represented by D. The outer diameter of national standard flange is also indicated by D, the center circle of bolt hole is indicated by K, the number of bolt holes is indicated by N, the sealing surface is indicated by D, F, the thickness of flange is C, and the inner diameter of large-diameter flange is indicated by B.
公称压力以PN表示，大口径国标法兰的材质主要是碳钢不锈钢合金钢为主，合金钢价格最贵，不锈钢次之，碳钢法兰最便宜。大口径国标法兰的主要产地分布在河北沧州，浙江温州，山西等，以沧州地区的大口径法兰产量最高，质量最好。
The nominal pressure is indicated by PN. The material of large-diameter national standard flange is mainly carbon steel and stainless steel alloy steel. The price of alloy steel is the most expensive, followed by stainless steel and carbon steel flange. The main producing areas of large caliber national standard flange are located in Cangzhou, Hebei Province, Wenzhou, Zhejiang Province, Shanxi Province, etc.