Melting method for HIC (Hydrogen Induced Crack)-resistant pipeline steel

Abstract

The invention provides a melting method for HIC (Hydrogen Induced Crack)-resistant pipeline steel. The melting method comprises the following steps: performing pretreatment on molten iron, melting ina converter, performing primary LF refining, performing RH vacuum treatment, performing secondary LF refining, performing VD vacuum treatment and performing continuous casting. The invention providesa stable control process for melting molten steel with ultra-low carbon, ultra-low sulphur, ultra-low phosphorus and high cleanliness; in the molten steel, C is less than or equal to 0.04, S is less than or equal to 0.001, P is less than or equal to 0.006, Ca is between 0.002 and 0.003, and the ratio of acid soluble aluminium to all aluminium is greater than or equal to 0.95; the component controlrequirements of the HIS-resistant pipeline steel on the ultra-low carbon, the ultra-low sulphur, the ultra-low phosphorus and the high cleanliness are met.

Description

technical field [0001] The invention belongs to the technical field of molten steel smelting production, and in particular relates to a smelting method of HIC-resistant pipeline steel. Background technique [0002] Hydrogen-induced cracking (Hydrogen Induced Crack-HIC) is caused by hydrogen atoms generated by electrochemical corrosion of steel in a wet hydrogen sulfide environment into the gaps inside the steel. Since the long strip-shaped MnS inclusions and other strip-shaped inclusions are easy to produce gaps with the steel matrix, and hydrogen atoms are easy to diffuse on the strip-shaped interface, when hydrogen atoms aggregate and combine into hydrogen molecules, a large pressure will be generated. , Then form a crack parallel to the rolling surface and along the rolling direction. [0003] Usually, the composition of anti-HIC pipeline steel is designed to be ultra-low carbon, ultra-low sulfur, ultra-low phosphorus, high cleanliness, reduce the content of manganese an...

AI Technical Summary

Problems solved by technology

The single slag method often requires deep dephosphorization of a large amount of slag, high-temperature tapping, etc., so the consumption of slagging materials and steel materials is high, and the dephosphorization rate of the single slag method is limited; Oxygen, process temperature, slag dumping and other processes are difficult to control

The duplex method needs to increase the special equipment and modify the layout of the production line, etc., which requires a large investment and poor flexibility; the LF-RH process requires extremely low carbon content when the converter is tapped, which not only increases the burden on the decarburization of the converter, but also requires more deoxidization. agent to increase the inclusions in the steel

The RH-LF process requires a high temperature of the molten steel when tapping the converter, which affects the dephosphorization rate of the converter, and the purity of the molten steel after LF refining is poor, the gas content is high, and the requirements for raw materials and operating levels are relatively high.