Low-niobium HRB400E coiled screw and production method thereof

Abstract

The invention provides a low-niobium HRB400E coiled screw and a production method thereof, and belongs to the technical field of steel smelting. The low-niobium HRB400E coiled screw comprises the following chemical components including, by mass, 0.21% to 0.24% of C, 0.35% to 0.50% of Si, 1.20% to 1.35% of Mn, less than or equal to 0.045% of P, less than or equal to 0.045% of S, 0.006% to 0.019% ofNb and the balance Fe and other impurities. A deoxidizing agent is added during tapping, and a carburant and ferrocolumbium are added when tapping is carried out by 1 / 4, wherein the addition amount of ferrocolumbium is smaller than or equal to 30 kg, all alloys are added when tapping is conducted by 3 / 4, high-pulling-speed low-melting-point covering slag is adopted as covering slag of a continuous casting crystallizer, 165 m<3> / h of water is distributed in the crystallizer, and 40 m<3> / h of secondary cooling section water is adopted; and the casting speed of a casting blank is 3.8-4.1 m / min,the initial rolling temperature is 1020-1050 DEG C, the spinning temperature is 920-980 DEG C, and finally a finished product is obtained. The characteristic that niobium has a nonlinear relation withthe mechanical property of steel is fully utilized in the low-niobium HRB400E coiled screw, the niobium component design is low, the niobium characteristic is utilized to the maximum extent, the strengthening effect of niobium is improved, a vanadium-nitrogen alloy is replaced, the niobium content is reduced as much as possible, and the alloy cost is reduced.

Description

technical field [0001] The invention relates to the technical field of iron and steel smelting, in particular to a HRB400E pan snail and a production method thereof. Background technique [0002] In the prior art, ferroniobium or vanadium nitrogen are used in the production of HRB400E snails, and the dosage is relatively high in composition design, but the effect has not been significantly improved. [0003] Use ferroniobium to produce 6mm, 8mm, 10mm size HRB400E screw, the composition design is generally: Nb0.025-0.032%, C0.21-0.25%, Si0.35%-0.50%, Mn1.20-1.35%, P≤ 0.045%, S≤0.045%, the tapping amount is 115 tons, and the ferroniobium addition amount is 50kg. Controlled cooling process of steel rolling: the temperature of the heating furnace is 1050-1100 ℃, and the steel obtained after spinning, after the mechanical performance test, meets the requirements of the national standard. The following table 1 shows the mechanical performance test results of the HRB400E disc scr...

AI Technical Summary

Problems solved by technology

Therefore, niobium-containing steel is less thermoplastic than vanadium-containing steel for continuous casting billet, so niobium-containing steel is more likely to produce slab cracks and stripping than vanadium-containing steel.

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