Method for producing strong annealed steel hot-rolled sheet coil

Abstract

The invention discloses a method of manufacturing a tough steel hot rolled strip coil. The molten steel, waste steel, chromic oxide and molybdenum oxide are mixed into a rotating furnace, and a fluxing medium is added in; the manganese oxide or manganese ore is added in at the earlier stage of blowing; the manganese oxide or manganese ore and the reducing agent are added in by the end of blowing, and nitrogen or argon is blew from bottom during the whole process; tapping is conducted when the components and the temperature of the molten steel are appropriate; during tapping, the composite deoxygener and the reducing desulfurating refining slag are added in the molten steel during tapping, and nitrogen or argon is blew from bottom of a steel ladle during the whole process. The steel ladle adds the metal aluminum in the molten steel from the CAS position to conduct deep deoxidation and microalloying; and then the increasing nitrogen agent, vanadium iron and ferrocolumbium are added in, and nitrogen or argon blowing is kept. The steel ladle is sent to the position of an LF refining furnace, the lime and reducing desulfurating refining slag are added in the LF refining furnace, argon is blew, electricity is supplied, the temperature is raised and argon is blew again, and the calcium line and the boron filament are fed at the later stage of refining; CSP is supplied for continuous casting, and the charging temperature of a cast slab is is more than 950DEG C; the heating temperature, the initial billet temperature, the rolling finishing temperature and the coiling temperature are well controlled. The tough steel hot rolled strip coil manufactured with the method has high strength and good tenacity.

Description

technical field [0001] The invention relates to a production method, in particular to a production method for hot-rolled tough steel coils applied in fields such as various construction machinery and mining machinery, such as large-scale electric shovels, dump trucks, drilling rigs, and coal mining machinery. Background technique [0002] Iron and steel products are the most important structural and functional materials that can be recycled and utilized in human society. At the same time, iron and steel enterprises are large energy consumers and environmental loaders. How to meet the ever-expanding market demand and reduce resource (or energy) and environmental load is also a major topic and research hotspot faced by scientific and technological workers in iron and steel enterprises. Improving the comprehensive performance of steel, especially greatly improving the strength and service life of steel and reducing steel consumption is an effective way to solve the above proble...

AI Technical Summary

Problems solved by technology

[0005] ①Adopt the composition design with higher alloy content. With the increase of strength, the types of alloys will increase, the total alloy content will increase, and the alloy cost will be higher;

[0006] ②After rolling, hot-rolled coils need to be quenched and tempered before entering the sales market. The process is long and energy-consuming, which increases production costs;

[0007] ③Mainly rely on the solid-solution strengthening of the alloy, the grain and structure are relatively coarse, and the toughness of the finished steel is relatively low (especially the high-strength grade steel), which limits the improvement of the strength grade of the steel and the scope of use

[0010] ②The thickness of CSP continuous casting billet is thin (50-150mm), the cooling rate is high, the billet structure is finer, and the precipitated two-phase particles are dispersed and finer

[0012] ④Although the strength of steel is still improved by the solid-solution strengthening of alloying elements, due to the characteristics of CSP itself, there are dispersed and fine second phase particles precipitated, and the toughness of the coil is improved, but the toughness improvement is limited

On the one hand, there are many types of alloys, and a higher content of precious alloying elements is used. On the other hand, the content of carbonitride-forming elements is relatively high, but the proportion of these elements combined with carbon and nitrogen to form carbonitride two-phase particles in the metallurgical process Small, the contribution of these alloy elements to the strength and toughness of steel is relatively low, resulting in low utilization of these alloys