High-strength, toughness, wear-resistant and corrosion-resistant bainite steel rail for heavy-duty railway and manufacturing method thereof

Abstract

The invention provides a high strength and toughness abrasion-resistant and corrosion-resistant bainite steel rail for a heavy haul railway and a manufacturing method of the steel rail. Components ofthe steel rail comprise, by weight percentage, 0.15%-0.25% of C, 0.80%-1.60% of Si, 1.00%-2.20% of Mn, smaller than or equal to 0.025% of P, smaller than or equal to 0.015% of S, 0.80%-1.80% of Cr, 0.20%-0.50% of Cu, 0.20%-0.50% of Mo, 0.10%-0.40% of Ni, 0.001%-0.003% of B, 0.15%-0.25% of Nb and the balance Fe and inevitable impurities. The steel rail is larger than or equal to 1450 MPa in tensilestrength, larger than or equal to 1300 MPa in yielding strength, larger than or equal to 13.0% in extending rate, larger than or equal to 90 J in normal temperature impacting absorbing energy AKU2, larger than or equal to 52% in fracture surface shrinking rate and not lower than 43 HRC in rail head cross section hardness.

Description

technical field [0001] The invention belongs to the field of metal materials, and in particular relates to a 75kg / m-grade high-strength, wear-resistant and corrosion-resistant bainite heat-treated steel rail for heavy-duty railway trunk lines and railway sections prone to severe rail corrosion. Background technique [0002] Steel rail is a key component that guides the train to run and transmits the wheel load to the ballast bed. The quality of the rail directly affects the operational efficiency and traffic safety of the line. It is understood that the annual transportation volume of my country's heavy-haul railways has exceeded 100 million tons, of which the annual coal transportation volume of the two heavy-haul railway lines Shuohuang Railway exceeds 200 million tons, and that of Daqin Railway exceeds 400 million tons. It has also been increased from the original 25t to 27t and 30t, all of which put forward higher requirements for the use of my country's heavy-duty railwa...

AI Technical Summary

Problems solved by technology

[0007] However, the above-mentioned rails are characterized in that they all use pearlite as the matrix. The disadvantage is that for pearlite rails, the combination of alloying and heat treatment is used to make the tensile strength reach 1300MPa, which is close to the limit, and cannot meet the requirements of heavy-duty railways. Requirements for high strength, toughness and wear resistance of steel rails

[0013] (1) The composition design in the method disclosed in the invention "Excellent Strength, Toughness, Fatigue Resistance and Wear Resistance Corrosion-Resistant Heavy Rail Steel" (application number 201010034200.0) can theoretically improve the strength, toughness and wear resistance of the rail, but The disadvantage is that as a rail steel with pearlite as the matrix, due to the high carbon content, even under the action of corrosion-resistant alloys, it still cannot prevent the preferential reaction of excess carbon with hydrogen, oxygen and corrosive gas environment, resulting in its lack of corrosion resistance. Corrosion performance, and in this method, noble alloy elements such as V, Ti, Ni are added at the same time, and the total content exceeds 1%, which significantly increases the production cost

[0014] (2) In the method disclosed in "A Corrosion-Resistant Bainitic Steel Rail" (Application No.: 201110077892.1), the bainitic steel rail does have certain corrosion resistance, but the disadvantage is that the alloy content is adjusted in the composition design There is a certain irrationality in adding, especially the Cr element is as high as 4.0%, and the strong hardenability leads to low-speed cooling (such as normalizing) to produce martensite, and the volume fraction can be as high as 20% to 30% of martensite, which is serious Damage ductility, almost no performance

At the same time, Mn+Cr exceeds 5.0%, which also significantly reduces the technological performance of the rail, the element segregation is intensified, and the production cost soars

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