Hollow wind turbine main shaft and profiling forging process and use thereof

A profiling forging process of a hollow wind turbine main shaft, comprising the following steps:

• step S1:
• billet hot-feeding:
• smelting alloying elements according to a formula to obtain a melt, casting the melt to obtain an ingot, and hot-feeding the ingot, wherein a mass ratio of Mn to Ni is in a range of 1:1.05 to 1:1.22;
• step S2:
• drawing-out and upsetting:
• reheating the ingot hot-fed in the step S1, followed by primary drawing-out, primary upsetting, secondary drawing-out, and secondary upsetting for a forging process to obtain a forged ingot, wherein before the forging process, the ingot hot-fed in the step S1 is reheated to 1,260° C. to 1,280° C. at a first heating rate of 70° C./hour to 80° C./hour for 5 hours to 6 hours;
• and the primary drawing-out is performed at a first forging ratio of 6.1 to 6.5, the primary upsetting is performed at a second forging ratio of 6.7 to 7.2, the secondary drawing-out is performed at a third forging ratio of 3.3 to 3.6, and the secondary upsetting is performed at a fourth forging ratio of 3.8 to 4.1;
• and the primary drawing-out and the primary upsetting are performed at a first temperature ranging from 1,080° C. to 1,260° C., and the secondary drawing-out and the secondary upsetting are performed at a second temperature ranging from 980° C. to 1,080° C.;
• step S3:
• ingot punching:
• reheating the forged ingot obtained in the step S2, followed by punching to obtain a punched forging;
• step S4:
• drawing-out and rounding:
• reheating the punched forging obtained in the step S3, and performing drawing-out and rounding on a shaft body of the punched forging to obtain a finished forging, wherein the punched forging is reheated to 1,200° C. to 1,220° C. at a second heating rate of 50° C./hour to 60° C./hour and then subjected to the drawing out;
• the drawing-out is performed with a first anvil width ratio of 0.6 to 0.8, a first reduction of 80 mm to 100 mm, a 90° clockwise turning mode, and a first feed of 0.4 to 0.6 of a first anvil width to obtain a drawn-out forging;
• the drawn-out forging is reheated to 1,200° C. to 1,220° C. before the drawn-out forging is subjected to the rounding;
• and the rounding is performed at a third temperature of 700° C. to 980° C. with a second anvil width ratio of 0.8 to 0.9, a second reduction of 10 mm to 20 mm, and a second feed of 0.7 to 0.8 of a second anvil width;
• and
• step S5:
• post-forging controlled cooling:
• placing the finished forging obtained in the step S4 into a first thermal insulation barrel for cooling, and air-cooling the finished forging to a room temperature to obtain the hollow wind turbine main shaft.