Technique for producing anti-acid pipeline steel by RH-LF-VD refining

Abstract

The invention relates to a technique for producing anti-acid pipeline steel by RH-LF-VD refining. According to the technique, convertor steel making and RH-LF-VD refining techniques are utilized to control the components of molten steel, thereby producing the low-carbon low-sulfur anti-acid (anti-HIC and anti-SCC) pipeline steel. The technique comprises the following steps: predesulfurizing molten iron, smelting in a convertor, carrying out RH vacuum decarburization, carrying out LF heating for desulfurization, carrying out VD vacuum decarburization, carrying out calcium treatment, carrying out soft blowing, continuously casting, and carrying out hot rolling. By using the secondary vacuum refining processes (RH vacuum refining and VD vacuum refining), the invention can reduce the decarburization load of the convertor, lower the oxidizability of the molten steel, eliminate the adverse effect of carburization in the LF furnace refining process, reduce the consumption of a strong deoxidizer, stabilize the production, ensure that the molten steel components are stably controlled within the production target, and satisfy the component control requirements of low carbon, low sulfur and high purity for anti-acid pipeline steel. The carbon content of the finished steel produced by the technical process provided by the invention can be controlled to 0.03%, and the sulfur content can be stably controlled to at most 0.0010%.

Description

technical field [0001] The invention belongs to the field of smelting and production of high-grade acid-resistant pipeline steel, and relates to a smelting process for accurately controlling the composition of steel by using converter steelmaking and RH-LF-VD refining. and tapping temperature, prolong the service life of the converter, and give full play to the refining desulfurization effect of the LF furnace. RH and VD vacuum treatment eliminates the adverse effects of carburization in the LF process, reduces the addition of strong deoxidizers, reduces deoxidized inclusions in steel, and improves purity. High temperature, uniform heat composition, stable production process, strong operability, and meet the composition control requirements of acid-resistant (HIC and SCC) pipeline steel for low carbon, low sulfur and high purity. Background technique [0002] Pipeline transportation is the most economical and reasonable transportation method for long-distance transportation ...

AI Technical Summary

Problems solved by technology

There is only one RH or VD vacuum refining process for the above processes, which increases the smelting burden of the converter, reduces the furnace age, and the purity of molten steel is poor. At the same time, the requirements for the LF and RH or VD vacuum refining process are also relatively strict, that is, the overall metallurgical process flow The requirements for raw materials, equipment, and operation level of each link are relatively high, and it is difficult to achieve stable production with low or ultra-low levels of carbon and sulfur in steel

The control of carbon and sulfur components in the finished steel is unstable, and the acid resistance (resistance to HIC and SCC) cannot be stably up to the standard

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