Low-cost production method of boracic low-alloy-structured steel sheet billet

Abstract

The invention provides a low-cost production method of a boracic low-alloy-structured steel sheet billet. The method comprises the following steps: (1) pretreating molten iron to ensure that the content of S (sulfur) in the molten iron is less than or equal to 0.005% and the bright surface with slag removal after desulfuration is greater than or equal to 85%; (2) performing tapping on steel with the roughing slag amount less than 4kg / t; (3) throwing 30kg of carbon powder for preliminary dexidation after the steel ladle bottom of the molten steel appears; adding 3.5kg / t of silicon iron of the steel when the steel tapping quantity reaches 1 / 3; immediately throwing a carburant after the addition of the silicon iron, wherein the adding amount of the carburant is based on the C (carbon) at a final point and the C increasing amount in alloy, namely, 35kg of carburant is added when 0.01% of carbon is increased in each time; and immediately adding 7kg / t of silicon manganese after the addition of the carburant; and (4) feeding different aluminum wires into the steel ladle according to the different oxygen contents of the molten steel after the steel ladle enters an alloy trimming station, wherein generally, the feeding quantity of the aluminum wires is less than 0.15kg / t of steel; and adding less than 0.15kg / t of ferroboron of the steel after the feeding of the aluminum wires, wherein performing intense agitation by adopting a top gun in a bottom argon blowing mode and then performing weak agitation during the alloying and processes under the condition that the total agitation time is greater than 10 minutes.

Description

technical field [0001] The invention belongs to the field of iron and steel smelting, in particular to a low-cost production method of a boron-containing low-alloy structural steel slab Background technique [0002] A small amount of boron can effectively improve the properties of steel, and it is widely used in the production of Q235, Q345 hot-rolled coils and other steel products. However, in the process of smelting and continuous casting, boron-containing steel mainly has the following problems. [0003] One is the unstable boron content. The content of boron element in steel is relatively low, generally 10-50ppm. In addition, its chemical properties are relatively active, and it has a strong affinity with oxygen and nitrogen. Controlling the stability of boron recovery rate becomes the key when producing boron-containing steel. Most boron-containing steels use LF or vacuum furnace refining process to reduce the end-point oxygen activity and nitrogen content to increase...

AI Technical Summary

Problems solved by technology

[0004] Second, boron-containing steel slabs are prone to cracks

[0005] Third, the cost of smelting is relatively high

In order to ensure the stability of boron content, LF or vacuum refining is usually used in the process, which increases the cost of the process; in the deoxidation process, deoxidizers such as aluminum and calcium with high prices are usually used for deoxidation, which increases the process cost; In terms of quality, in order to eliminate the impact of cracks in the slab, it is usually necessary to clean the slab, which increases the cost of cleaning and the loss of metal materials