Production method of phi 512 mm*37 mm high-grade steel coupling blanks

The invention provides a production method of phi 512 mm*37 mm high-grade steel coupling blanks. The production method comprises the following steps: incoming inspection: phi 457*39.5 mm female pipes with the steel grade of TP110V and the steel type of 28CrMo45V are selected to serve as raw materials; structures of core rods: the core rods comprise flanges A, alloy sections B, core head bodies C and core head guide areas D, wherein the flanges A are 550 mm, the total lengths of the alloy sections B are 2 m, the thicknesses of the core head bodies C are 120 mm, and the thicknesses of the core head guide areas D are 75 mm; and hot expansion: the hot expansion process system is established, and the process parameters are determined: the expansion molding temperature is 910-930 DEG C, the hot expansion push molding speed is 70+-10 mm/min, and the diameters of the female pipes are thermally expanded from phi 457.0*39.5 mm to phi 512.0*37.0 mm after the hot expansion. The effective production method is provided for producing high-grade steel coupling materials with large caliber. The production method solves the equipment damage in the production of the high-grade steel coupling materials, decreases the tool cost, and improves the quality and the yield of steel pipes.