大口径法兰常见的有平焊法兰和对焊法兰。丝扣法兰是没有大口径的。在现实的生产与销售中，还是平焊产品的比例占得多。平焊大口径法兰和对焊大口径法兰的结构和使用的范围不同，能够展现的特点和优点也会不同，所以在使用时要针对不同的范围进行使用，保证法兰发挥重要的作用。
Large diameter flange has common flange and butt welding flange. There is no large diameter threaded flange. In the production and sale of reality, or welding products accounted for much. The range of structure and use of welding of large diameter flange and butt welding of large diameter flange is different, can show the characteristics and advantages will be different, so when used according to different scope of use, which play an important role in the flange.