Austenitic stainless steel large-open-angle section manufacturing method

The invention provides an austenitic stainless steel large-open-angle section manufacturing method which comprises the steps that a shell is divided into a plurality of same segmented shells, the segmented shells are unfolded and lofted, and blanking, groove preparation and compression molding are conducted on each segmented shell; designing a molded surface tool; assembling a molded surface tool; assembling and welding the sectional shells, namely vertically assembling the large-opening-angle section shells layer by layer from an outlet, firstly assembling the sectional shells at the outlet, then assembling the other sectional shells layer by layer until the assembling is completed, and finally, performing tack welding on the sectional shells and a molded surface tool; after the whole shell part is welded, the reinforcing ribs are spliced, and welding is completed; measuring the projection length of the whole shell in the central axis direction, measuring the inner perimeters of an inlet and an outlet of the