NOVELTY - Wind power main shaft flange upsetting process comprises: (a) preparing the wind power flange steel billet by heating the steel-making furnace, adding steel raw material, refining into the low-alloy high-strength steel billet, continuously casting the steel billet into a billet, forging the billet; (b) carrying out multiple alternating first and second upsetting process as the first upsetting stage; (c) placing a lantern ring and adding carbon steel sleeve on the outer ring of forging; and (d) carrying out multiple alternating first and second upsetting process as the second upsetting stage.    USE - The method is useful for upsetting wind power main shaft flange.    ADVANTAGE - The method adopts the rotary partial upsetting process, combines the turning process to conduct the first upsetting stage, and carries out the second upsetting stage process on the forging outer ring lantern ring to reduce the forging cost and labor intensity of workers, and reduce the non-uniformity deformation.    DETAILED DESCRIPTION - Wind power main shaft flange upsetting process comprises: (a) preparing the wind power flange steel billet by heating the steel-making furnace to 1300 degrees C, adding steel raw material, refining into the low-alloy high-strength steel billet used for wind power flange; where the chemical components of the low-alloy high-strength steel comprise (in wt.%): carbon (0.25-0.60), silicon (0.35-0.50), manganese (1.2-1.70), phosphorus (0.015-0.025), sulfur (0.012-0.02), chromium (0.30-0.80), molybdenum (0.10-0.30), vanadium (0.15-0.30), nickel (0.30-0.50), copper (0.15-0.3), nitrogen (0.015-0.05), titanium ( less than or equal to 0.2), niobium ( less than or equal to 0.06) and iron (balance amount); continuously casting the low-alloy high-strength steel billet into a billet of theta as 1500 mm, forging the billet to obtain the forging used for wind power flange; (b) carrying out multiple alternating first and second upsetting process as the first upsetting stage comprising hanging the vertical wind power main shaft flange forging into the upsetting device composed of an upsetting mold and a rotary working table, and fixing the forging on the working table, where the first upsetting process comprises firstly upsetting one part of the forging, rotating the rotary working table, upsetting the other part of the forging, continuously upsetting and rotating until the whole surface of the forging is finished with the upsetting process to ensure the round shape of the forging; carrying out the second upsetting process of the first upsetting stage comprising lifting the forging placed on the rotary working table by a hanger, turning 180 degrees , fixing on the rotary working table, using the hydraulic press to carry out the second upsetting process on the forging resulting from the first upsetting, where the process of the second upsetting is identical with the process of the first upsetting, repeating the first and second upsetting processes until the height of the forging is half of the original height of the forging; (c) placing a lantern ring and adding a carbon steel sleeve on the outer ring of the forging obtained in the step (b); and (d) carrying out multiple alternating first and second upsetting process as the second upsetting stage comprising carrying out the first upsetting process of the second upsetting stage by firstly upsetting one part of the forging, finishing the forging of the part, rotating the rotary working table, upsetting the other part of the forging, and continuously upsetting and rotating until the whole surface of the forging is finished with the upsetting process; carrying out the second upsetting process by lifting the forging placed on the rotary working table by the hanger, turning 180 degrees , then fixing on the rotary working table, using the hydraulic press to carry out the second upsetting process on the forging resulting from the first upsetting, where the process of the second upsetting is identical with the process of the first upsetting, repeating the first and second upsetting processes until the forging is upset into the wind power main shaft flange of required size, removing the lantern ring and finishing the upsetting process.