A kind of production method of heavy rail steel for wheel guard rail

Abstract

The invention provides a production method of heavy rail steel for a guard rail. The production method comprises the steps that slag materials are added during LF refining operation for preparing high-alkalinity white slag with the binary alkalinity being 3.0-5.0 for refining; when the sulfur content of molten steel is lower than or equal to 0.012 wt%, a slag modifier is added for slag modifying treatment, and the alkalinity of slag is controlled to 1.5-2.0; ferrotitanium is added to control the titanium content of the molten steel to 0.015-0.025 wt%; then soft blowing, discharging out of a station and steel feeding are conducted; and in the step of slow cooling of a cast blank, the cast blank is taken down from a line through a clamp and placed into a slow cooling pit for slow cooling treatment, the temperature for placing the cast blank into the pit is not lower than 700 DEG C, the temperature for discharging the cast blank out of the pit is not higher than 150 DEG C, and thus good thermodynamic conditions for diffusion of hydrogen in the cast blank are provided. According to the production method, the RH or VD refining step in the prior art is omitted, the production technological process of the heavy rail steel for the guard rail is simplified, and the production cost is reduced; and various impurities in the cast blank are controlled to 2.0 grade or below, center segregation and porosity defects in the cast blank are effectively reduced, and the requirement for the quality of the guard rail is completely met.

Description

technical field [0001] The invention relates to a production method of heavy rail steel for wheel guard rails, and belongs to the technical field of steelmaking technology. Background technique [0002] Wheel guard rails are divided into two categories: single (double) side guard rails for sharp curve anti-derailment lines and protective guard rails for bridges, etc., which are used to prevent train derailment. "High speed, heavy load, and increased traffic density" has become the general trend of railway development today. With the increase of train speed and the weight of steel rails, higher requirements are put forward for the purity, internal and surface quality of wheel guard rails. [0003] At present, the main production processes of heavy rail steel include: converter smelting, LF+RH or VD double refining and bloom continuous casting process. my country's patent "a method for controlling sulfur content of heavy rail steel" (patent number: 201110403458.8) controls th...

AI Technical Summary

Problems solved by technology

my country's patent "A Method for Controlling Sulfur Content of Heavy Rail Steel" (Patent No.: 201110403458.8) controls the sulfur content of molten iron entering the furnace. When the sulfur content of molten iron entering the furnace is higher than 0.060%, desulfurization treatment is performed to control the VD refining process The technical problem of sulfide inclusions in the middle cannot be eliminated, and the purity of molten steel can be improved; the common feature of the existing heavy rail steel production methods for guard wheel rails is the use of molten iron desulfurization treatment, strict requirements on the composition of the molten iron in the furnace, and all of them have been subjected to RH or VD vacuum Refining treatment, complex production technology, increased production costs; if hot metal desulfurization treatment and vacuum treatment are not used, the content of harmful gases and inclusions in the steel will be high, which will easily cause serious defects such as white spots, cracks, and point-like inclusions exceeding the standard. Seriously endanger the product quality of the guard rail