Preparation process of H08A steel

Abstract

The invention provides a preparation process of H08A steel. The preparation process comprises the following specific steps of first, smelting in a converter, wherein magnesium alloy is added in the tapping process to carry out pre-deoxidation and argon blowing, and the free oxygen content of molten steel is controlled to range from 80 ppm to 100 ppm; second, LF refining, wherein calcium is added in the process to remove oxygen again, and the free oxygen content is controlled to range from 10 ppm to 20 ppm after LF refining heating of the molten steel is finished; and third, continuous casting;wherein according to the feeding manner of adding the magnesium alloy in the first step, powdery magnesium alloy is blown into the bottom of a steel ladle by using carrier gas. According to the preparation process of the H08A steel, the section of a produced casting blank (8 hours of continuous casting) sample produced is free of any obvious bubbles, the central porosity grade is less than or equal to 0.5 grade, the central segregation grade is less than or equal to 0.5 grade, other obvious defects do not exist, and the percent of pass is 99%; and meanwhile, in the cross section of a steel body with the area of 100 * 100 millimeters, the number of inclusions is no larger than 30, and the maximum diameter of the inclusions is no larger than 20 micrometers.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a method for smelting H08A steel. Background technique [0002] H08A steel is an important raw material for welding rod production. It is a kind of low-carbon steel. One of the biggest differences from other steel types is to ensure the chemical composition of the finished steel. The requirements for carbon, aluminum and oxygen in the steel are relatively strict. In the production process of H08A steel, it is necessary to add a deoxidizer for deoxidation. Generally, aluminum is used as a deoxidizer, and the addition of aluminum deoxidizer will generate a large number of inclusions, which will easily block the tundish nozzle, affecting the pourability of molten steel and continuous casting. However, if the deoxidizer is insufficient, bubbles will be generated in the slab due to poor deoxidation. Therefore, in the production of H08A steel in the prior...

AI Technical Summary

Problems solved by technology

[0003] CN108950124A discloses a production method of welding rod steel H08A, which belongs to the field of iron and steel metallurgy technology, and solves the technical problems that the continuous casting time is short and the casting slab has obvious bubble defects in the production process of welding rod steel H08A

[0004] Although the technology of reducing air bubbles and inclusions in the molten steel casting body has been studied in the prior art, the effect on the control of air bubbles and inclusions is not obvious on the whole, and the addition method of the deoxidizer is not optimized. During the deoxidation process, It is easy to cause waste of materials and even safety problems

Images