Abstract: The reason of the oxide scale of T12 steel containing Cr, Ni, Mo and other alloy elements in not being easy to be removed under the existing equipment of Hangang has been analyzed. Through the experiments of heating process parameter optimization, descaling water tank nozzle optimization, the optimal process method is selected to solve the problem of unclean descaling of high-pressure boiler tube casting billet. After the test, the heating time of 150 mm x 150 mm square billet is controlled within 90 ~ 100 min, and the furnace residual oxygen is controlled within 2% , blocking the water ring nozzle of mutual interference descaling and decreasing nozzle jet angle from original 38° -40° to 33° ~35°, there is no scale residue on the surface of continuous casting billet after descaling, and there is no surface defect in the finished product.