A production process of low carbon weathering steel

Abstract

The invention discloses a production technology of low-carbon weather-resistant steel, belongs to the field of rolled steel preparation, and particularly relates to a method for controlling the surface quality of a rolled product of the low-carbon weather-resistant steel containing copper and stibium. Through design of liquid steel components, optimization of a continuous casting process and cooling control after a casting blank is discharged from a withdrawal and straightening machine, the surface quality of the casting blank is improved; enrichment and precipitation of low-melting point elements Cu and Sb on the crystal boundary in the casting blank cooling process are effectively inhibited; a hot charging process is adopted; the tapping interval is improved; the heating cost is reduced; the heating time in a furnace is shortened; the heating temperature is controlled; by virtue of high-temperature quick calcination, secondary enrichment of the low-melting point elements Cu and Sb along the austenite crystal boundary in the heating process is relieved; through the measures, the surface quality problem of the rolled product caused by corner cracks and crystal boundary cracks on the casting blank surface is greatly improved; and the barreling attrition rate of the rolled product is effectively reduced.

Description

technical field [0001] The invention belongs to the field of steel preparation, and in particular relates to a method for controlling the surface quality of rolled low-carbon weather-resistant steel containing copper and antimony. Background technique [0002] Copper and antimony weathering steels are widely used in the manufacture of economizers, air preheaters, heat exchangers, evaporators and other equipment that serve in high-sulfur flue gas to resist condensation corrosion of sulfur-containing flue gas. After long-term inspection, copper- and antimony-containing weather-resistant steels are generally considered to be one of the ideal "sulfuric acid low-temperature corrosion-resistant" steels in China, and they are resistant to hydrochloric acid (HCl), hydrofluoric acid (HF), caustic soda (NaOH), Sodium chloride (NaCl), has strong corrosion resistance. In addition, in order to maintain good welding performance, the carbon content should not be too high. At present, the...

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Problems solved by technology

[0005] Patent CN201210463981.4 and Chen R.Y. reported that the effect of suppressing copper brittleness can be achieved by adding nickel with copper content in a ratio of 1:1 or higher. However, the addition of a large amount of Ni not only increases production costs, but also It also increases the tendency of the corrosion resistance of the steel to deteriorate; Liang Wen et al. tried to add a certain amount of rare earth to the weathering steel, and reduced the amount of Ni added through the fixation of the rare earth lanthanum, cerium, and yttrium to the low melting point elements, but The application of rare earths in steel is still immature. On the one hand, the price of rare earths is relatively expensive. On the other hand, improper treatment of rare earths will increase the inclusions in the steel and deteriorate the performance of the steel. Chihiro Nagasaki et al. have suppressed the enrichment of copper in copper-containing steel at grain boundaries by adding elemental boron, but this control method only stays in the laboratory stage, and its applicability is relatively limited, and it is difficult to widely promote it to industrial production

[0006] It is also worth noting that most of the current patents and research only control a single production link in the steelmaking or rolling process, and there is no comprehensive analysis from the beginning of composition design to steelmaking slab, casting slab transfer, and rolling. The whole process is controlled, and rarely involves the impact of higher content of antimony on surface quality

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