... 2>Ensure you quality,timely delivery; 3> approved by ASTM seamless alloy tube manufacturer: Material: 12Cr1MoV, P22(10CrMo910), T91, P91, ... Official API Monogram.2> Boiler and Super-heater Pipes,Seamless Pressure Pipes had been approved by CCS.3> The quality ... cooperation with Chengdu Steel Group Co., Ltd., Baotou Steel Group Co., Ltd., Baoshan Steel Corporation and Tianjin Steel Pipe Group Co., ...