High-strength weathering steel and method for producing same

Abstract

The invention relates to high-strength weathering steel and a method for producing same. The high-strength weathering steel comprises the following components by weight percent (wt%): 0.001-0.004 percent of C, 0.10-0.30 percent of Si, 0.40-0.70 percent of Mn, 0.020 percent of P or less, 0.008 percent of S or less, 2.50-3.50 percent of Cr, 0.20-0.40 percent of Ni, 0.25-0.50 percent of Cu, 0.01-0.03 percent of Re, 0.02-0.06 percent of Al, 0.001-0.004 percent of Ca, 0.001-0.005 percent of N, 0.01-0.03 percent of Ti, 0.01-0.03 percent of Nb and the balance of Fe and other inevitable impurities. After the molten iron is fully deoxidized and before the refining of the molten iron is finished, ferrotitanium is added to steel ladle, a Ca wire is fed to the steel ladle, a Re wire is fed into a continuous casting crystallizer, and a slab is reheated at 1180-1300 DEG C; the two-stage controlled rolling is adopted; the ratio of the thickness of the intermediate slab to the thickness of the finished product is controlled at 3.0; the refining outlet temperature is controlled at 890-1050 DEG C; the finishing rolling temperature is controlled at 800-860 DEG C; the rate of cooling after finishing rolling is controlled at 10-15 DEG C per second; and the winding temperature is controlled at 580-640 DEG C. The invention has the advantages that the relative corrosion rate of the weathering steel subjected to the 72h periodic infiltration is less than 30 percent compared with that of the steel Q345B, the weathering performance of the weathering steel is obviously better than the traditional high-strength weathering steel, and the weathering steel of the invention has the yielding strength of more than 550 Mpa and the elongation rate of more than 24 percent. The high-strength weathering steel of the invention can be applied to the fields of the railway truck, the container, the bridge, the communication, the power tower and the like.

Description

technical field [0001] The invention relates to a high-strength weather-resistant steel and a manufacturing method thereof, belonging to the technical field of weather-resistant steel. Background technique [0002] Weathering steel, as a kind of steel with a large quantity and a wide range, plays an important role in the fields of railway wagons, containers, bridges, communications and power towers. The main directions for the development of weathering steel technology are: 1) High strengthening; 2) High weather resistance. Under the background of "increasing speed, reducing self-weight, and increasing load" in my country's railway freight car transportation, high-strength weathering steel is the first to be applied in batches to railway freight cars. At present, the quantity of high-strength weathering steel for railway wagons is the largest, with an annual demand of about 300,000 tons. Its composition system is Cr-Ni-Cu system, and its yield strength grade is mainly 450MP...

AI Technical Summary

Problems solved by technology

Therefore, in the actual use process, there are still two problems: 1) the existing weather resistance index is difficult to meet the technical requirements of the railway wagon design service life of 25-30 years, and the replacement rate of the wagon body steel plate during factory repair 2) Affected by low weather resistance, steel plates for truck bodies cannot continue to be thinned

Although the high weathering steel invented by this patent has good technical indicators, its Cr content is as high as 4.50-5.50%, the alloy cost is high and the welding performance is not good

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