High-niobium Q460-grade fire-resistant steel and manufacturing method thereof

Abstract

The invention relates to high-niobium Q460-grade fire-resistant steel and a manufacturing method thereof. The high-niobium Q460-grade fire-resistant steel comprises the following components in percentage by weight: 0.01 to 0.20 percent of C, 0.1 to 0.4 percent of Si, 0.5 to 1.5 percent of Mn, 0.1 to 1.0 percent of Cr, 0.01 to 0.2 percent of Mo, 0.05 to 0.15 percent of Nb, 0.01 to 0.05 percent of Ti, and the balance of Fe. The manufacturing method comprises the steps of heating a steel billet to 1150 to 1250 DEG C, thermally preserving the steel billet for 120min to 200min, and cooling the steel billet in the air, wherein the coarse rolling finished-rolling temperature is 1000 to 1050 DEG C, and the reduction rate is 2 to 5; the precision rolling starting-rolling temperature is 900 to 1000 DEG C, and the precision rolling finished-rolling temperature is 800 to 900 DEG C; and the re-reddening temperature is 350 to 550 DEG C, and the cooling rate is 10 to 25 DEG C / S. By adopting the manufacturing method, the grade of the finished product steel is improved while the additive amount of heavy metal Mo is reduced.

Description

technical field [0001] The invention relates to a low-alloy high-strength steel and a manufacturing method thereof, in particular to a high-niobium Q460 fire-resistant steel and a manufacturing method thereof. Background technique [0002] When the temperature of ordinary building steel reaches 400°C, the yield strength will drop to half of the room temperature strength, and when the temperature reaches 600°C, the strength will be basically lost. Therefore, when building large-scale steel structure buildings, industry norms and standards require coating A layer of fire-resistant coating is used to enhance the ability to resist fire, but spraying refractory materials doubles the cost of the building, prolongs the construction period, reduces the effective indoor area, and the splash of spraying operations also pollutes the environment; therefore, one of the development trends of modern buildings One is the requirement to reduce fire-resistant coatings, and the requirement to ...

AI Technical Summary

Problems solved by technology

[0008] The steel grades protected by the above four domestic and foreign patents are all mainstream refractory steel varieties currently on the market. It is not difficult to see from the above data that the current refractory steel uses Mo as a high-temperature strengthening element in the composition design, and the addition of precious alloys is relatively large. Low steel grade or high manufacturing cost, these disadvantages greatly limit the market application of refractory steel

Images