Inclusion control method for pipeline welding wire steel

Abstract

The invention provides an inclusion control method for pipeline welding wire steel, which comprises the following steps of: (1) converter back deoxidization: performing strong deoxidization on molten steel by adopting aluminum melt on the rear converter after the welding wire steel converter finishes smelting; (2) low-frequency (LF) converter refining: after the oxygen activity of the molten steel of the rear converter is not more than 20*10<-6>, performing LF converter refining treatment on the molten steel; forming slag in 10 to 20 minutes when the LF refining begins, and adding fluorite, wherein the alkalinity of top slag is 1.5 to 4.0, and the content of Al2O3 is 15 to 25 percent; adding titanium and iron at the medium term of refining for further deoxidization, wherein the LF argon blowing time is 25 to 35 minutes, the argon flow is 300 to 400N1 / min, and the temperature of the molten steel in the refining process is between 1,550 and 1,630 DEG C; and (3) molten steel argon blowing and stirring: after the oxygen activity of the molten steel is not more than 15*10<-6>, performing weak argon blowing and stirring on the molten steel, wherein the argon flow is 50 to 150N1 / min, andthe argon blowing time is 3 to 8 minutes. The method can reduce the size of inclusions, properly control the number of the inclusions and improve the yield of elements such as Ti, B and the like in the steel.

Description

technical field [0001] The invention belongs to the technical field of iron and steel smelting, and in particular relates to a method for controlling inclusions of pipeline welding wire steel. Background technique [0002] Pipeline welding wire steel is used in the welding engineering of pipeline steel, which has a great impact on the service performance of pipelines. The size and quantity of inclusions in pipeline wire steels have a significant effect on the quality of the weld metal. Smaller-sized inclusions can have a beneficial effect on the structure and performance of the weld, while larger-sized inclusions can deteriorate the performance of the weld. [0003] In order to ensure that the size and quantity of inclusions in pipeline welding wire steel are small and appropriate, the method of argon blowing and stirring in the refining process is usually used in the smelting process of pipeline welding wire steel to remove large-size inclusions in the steel, so as to redu...

AI Technical Summary

Problems solved by technology

However, since the pipeline welding wire steel generally contains easily oxidizable elements such as Ti and B, if the argon gas stirring time is too long, the Ti and B elements in the steel will be oxidized in large quantities.

Images