Corrosion-resistant ultra-fine pearlite material with addition of rare earth ce and nb elements

Abstract

The invention discloses a corrosion-resistant ultra-fine pearlite material added with rare earth Ce and Nb elements, and its chemical cost is calculated as: C: 0.85%-1.1%, Mn: 0.9%-1.2%, Si: 0.7%-0.9% %, Cr: 0.3% to 0.5%, Cu: 0.2% to 0.5%, Nb: 0.02% to 0.04%, Ce: 0.02% to 0.05%, P: 0.02% to 0.04%, S≤0.003%, and the balance is Iron Fe and impurities. The hypereutectoid steel rail prepared by adopting the corrosion-resistant ultrafine pearlite material of the present invention has a structure of nano-scale pearlite lamellar structure, and the lamellar spacing is about 62nm to 83nm. The rail has excellent strength, toughness, hardness and corrosion resistance. It is more suitable for high-speed and heavy-haul railway lines.

Description

technical field [0001] The invention belongs to the technical field of corrosion-resistant ultrafine pearlite materials and hypereutectoid steel rails, and in particular relates to corrosion-resistant ultrafine pearlite materials added with rare earth Ce and Nb elements. Background technique [0002] As an efficient and green transportation, high-speed railway has shown a strong momentum of vigorous development around the world. It not only promotes the harmonious development of the world and the region, but also saves precious oil resources and greatly reduces carbon emissions. By 2020, my country plans to build a 150,000-kilometer high-speed railway network of "four vertical and four horizontal", and there is an urgent need for rail products with higher strength and wear resistance. The highest can only reach about 430HB, the rail has low strength, low hardness, low carbon content, and poor wear resistance. At present, to improve the strength, toughness and wear resistance...

AI Technical Summary

Problems solved by technology

The process disclosed in the above patents has limited strength and wear resistance of hypereutectoid steel rails, and cannot meet the current performance requirements for high-strength steel rails.

[0004] The Chinese patent publication with the notification number CN1304618C: Although the carbon content of pearlitic steel is as high as 1.4%, and the carbide form is controlled by further adding microalloying elements such as Nb, V, Mo, and B to obtain higher strength, the subsequent heat treatment process is relatively difficult to control. complex

Notification No. CN101818312B, Publication No. CN1884606A Chinese patent method of low-temperature reheating combined with accelerated cooling of the rolled steel rail, controlling pearlite phase transformation to obtain fine pearlite to improve toughness, the existing problem is that reheating will cause coarse carbides, and instead Reduce toughness, but also increase energy consumption and production costs

The nano-pearlite steel rail described in the Chinese patent with the notification number CN104032222B needs to be stress-relieved and tempered, which not only makes the production process complicated, but also causes impurity elements to segregate at the grain boundary, which is also detrimental to toughness. The cross-sectional shape is not suitable for tempering heat treatment to improve toughness

The hypereutectoid steel rail described in the Chinese patent with publication number CN1522311A has low plasticity, the rail is easy to break, and proeutectoid cementite is easily formed in the segregation zone in the center of the slab, which deteriorates the performance of the rail, and the welding carbon equivalent is high, and the welding performance of the rail is poor. , it is easy to form reticular proeutectoid cementite in the welding process

[0005] In addition, the patent application with the publication number CN104060187B developed a high-carbon steel rail with the addition of copper, chromium and other corrosion-resistant alloy elements, but failed to solve the side effects caused by the addition of copper and chromium on the toughness and welding performance of high-carbon rail steel problems, reducing the safety of rail use

In the Chinese patents with notification numbers CN104060187B and CN100519670C, thermal spraying of aluminum-zinc coatings and corrosion-resistant nano-coatings on the surface of rails is used to improve the corrosion resistance of rails, but the coating process is complicated, and there are not only problems such as splash pollution of coating materials, but also high cost. The key is that the coating is easy to peel off during the rail straightening process, and the corrosion resistance is not ideal, so it cannot be widely used

[0006] All in all, the following technical problems exist in the hypereutectoid steel rails: it is difficult to match the high strength, toughness and fatigue performance of the hypereutectoid steel rails at the same time, and the rails are changed frequently; the post-sequence heat treatment process of the hypereutectoid steel rails is complicated, The process is not easy to control, which is not conducive to energy saving and emission reduction, etc.; and the corrosion-resistant hypereutectoid steel rails reduce toughness and welding performance due to the addition of copper and chromium. These factors greatly limit the popularization and application of hypereutectoid steel rails

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