Material:Carbon Steel or Alloy Steel UT TEST:100% UT INSPECTION subject to SEP1921 E/e The hollow shafts are used for wind power generation high-speed gear case ,high-speed gear case,metallurgy, roll,oil extraction,mining,chemical industry, hydraulic pressure products, port and shipping driving machines and so on. And it is made of many kinds of material, carbon steel, alloy steel, stainless ...