Shield body machining method for large-diameter shield tunneling machine

The invention discloses a shield body machining method for a large-diameter shield tunneling machine. The method includes the following steps that S1, raw materials of a front shield are selected, steel is preliminarily formed into a blank material, the blank material is heated, subjected to heat preservation and cooled, and the blank material is heated again, subjected to heat preservation and rapidly cooled; S2, the blank material is quickly cooled in cooling liquid after heating and heat preservation and continues to be heated, the blank material is slowly cooled at room temperature after heat preservation, the cooled blank material is placed in liquid nitrogen for 2-3 h and then taken out, and after the temperature of the blank material rises up again under the room temperature condition, a primary finished product is obtained for use; S3, the primary finished product is automatically cut, inner holes are machined in the primary finished product, and rib plates, partition plates and conical plates are wel