目前市场上面最常见的是通过卷制和焊接来实现的，这种大口径法兰的使用压力有一定的限制，当压力达到一定程度后，就不能用这样的了；

At present, the most common part of the market is achieved by rolling and welding. The pressure of the large diameter flange is limited. When pressure reaches a certain level, it can't be used.

另外一种就是直接锻打出来的，无焊接的大口径法兰，能承受的压力指数远远高于卷制和焊接的，这种最大的工艺难度在于，毛坯的锻打，而且对设备和做工都有一定的要求，需要的人工成本相当高，所以除了一些大型的工程采购使用，其他一般不采用这种方式来制作。

Another is the direct forged out of the large caliber flange without welding, can withstand the pressure index is much higher than that of rolling and welding process, the biggest difficulty is that rough forging, and has certain requirements on equipment and workmanship, labor costs need is very high, so in addition to some the use of other large project procurement, generally do not use this way to make.