High-alkalinity synthetic slag for pipeline steel secondary refining

Abstract

The invention belongs to the technical field of steelmaking, particularly provides a high-alkalinity synthetic slag for pipeline steel secondary refining which is especially suitable for desulfuration of molten pipeline steel and control and removal of occluded substance. Chemical components of the high-alkalinity synthetic slag for the pipeline steel secondary refining specifically include, by weight, CaO 45-60%, Al2O3 15-30%, MgO 6-10%, SiO2 5%, CaF2 5-10%, MnO+FeO 0.6% and initial sulfur capacity in the slag 0.05-0.15%, wherein the alkalinity is 8-15. Compared with traditional synthetic slag for pipeline steel refining, the high-alkalinity synthetic slag has high sulfur capacity (KTH model CS 0.01-0.02). According to the relation of the sulfur capacity, the slag amount and desulfurization rate, the sulfur capacity is higher, the smaller the slag amount required by the same desulfurization rate is. By using the synthetic slag with high sulfur capacity, the refining slag amount can be decreased, and the cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of steelmaking, in particular to a high-alkalinity synthetic slag for refining outside a furnace, and is especially suitable for desulfurization of pipeline steel molten steel and controlled removal of inclusions. Background technique [0002] With the development and utilization of my country's oil and natural gas resources, low-alloy, high-strength, high-toughness high-grade pipeline steel will become a class of steel that is in great demand in the national economy in this century. Oil pipeline steels are mostly used in remote areas with harsh environments and under corrosive conditions, which require high quality. Pipeline steels are required to have high strength, high toughness, good weldability, good resistance to hydrogen-induced cracking (HIC) and H 2 S Corrosion (SCC) Capability. Both HIC and SCC of pipeline steel are closely related to sulfur and inclusions in steel. For pipeline steel, reducing t...

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Problems solved by technology

This causes significant differences in the isotropic properties of the product, which deteriorates the plasticity of the steel and the shrinkage of the area along the thickness direction, causing the steel product to be damaged by various complex stresses.

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