Analysis of the Causes of Flocculent Flow in the Continuous Casting Process of Pipeline Steel X65

Abstract

This article analyzes the causes of flocculent flow in the continuous casting process of low-carbon， low sulfur， and low oxygen aluminum killed steel X65， and finds that the cause of flocculent flow in the stopper rod is the adhesion of high Ca calcium aluminate to the head of the stopper rod. In the early stage of pouring， the head of the stopper absorbs heat， causing a sharp decrease in the temperature of the surrounding steel liquid， and the precipitation of high melting point calcium aluminate is adhered to the head of the stopper， causing the stopper curve to rise. In addition， by thermodynamic calculations， the Ca content required to form 12CaO·7Al2O3 in low-carbon， low sulfur， and low oxygen aluminum killed steel X65 at 1 540 ℃ is 16×10-6， excess Ca further reacts to form high melting point calcium aluminate. Under the condition that magnesium refractory materials are used in all areas in contact with the molten steel， such as the working layer of the intermediate ladle， stopper rods， nozzles， and bowl mouths， and in the production of low-carbon， low sulfur， and low oxygen aluminum killed steel， the more Ca content is fed into the molten steel， the more severe the upward movement of the stopper rods. Using high alkalinity slag system and Al to reduce O and S in steel， and then controlling the Ca feeding amount between 0.065 0～0.071 5 kg/t， and controlling the calcium content in the tundish between （10～15）×10-6 can effectively control flocculent flow.

Keywords

• flocculent flow； calcium treatment； aluminum content； calcium aluminate； pipeline steel