Quasi bainitic steel

Abstract

A quasi-bainite steel with high strength, gouthness, weldability and antiwear performance for railway contains C (0.10-0.25 wt.%), Si (0.80-2.60), Mn (1.0-3.5), Mn (0.2-0.8), Cr (0.3-2.0), Ni (0.50-1.5), Nb (0.01-0.07), V (0.10-0.70) and Fe (rest). Its preparing process features that the electric furnace or converter is used for smelting while the contents of N2, H2 and O2 in molten steel are controlled.

Description

1. Technical field: [0001] The invention relates to a steel for railways, in particular to a quasi-bainite steel with high strength, high toughness, weldability and wear resistance. 2. Background technology: [0002] The railway is the main artery of the national economy, and it is of great significance to promote the development of industrial and agricultural production. At present, among the more than 70,000 kilometers of railway operating lines in the country, about 50,000 kilometers of railways are short-gauge lines, and there are 40 pairs of lines per kilometer. Rail joints, even in seamless line sections, there are still rail joints before and after turnouts, long rail buffer zones, ballastless bridge lines, etc. When the train passes through these joints, it will generate a strong and complex impact force at the joints, which will cause plastic deformation of the rail joints, resulting in defects such as buckle mouths, low-slump line muddying, and muddy defects at the...

AI Technical Summary

Problems solved by technology

This invention changes the mechanical properties of steel by adding niobium into molten steel. Its alloy content is low, the production process is simple, and the mechanical properties of the product have reached the world's advanced level, but its high carbon content is not suitable for use in low temperature regions; Another example: Chinese patent (publication number is CN1375573A, application number is 01138962.1) discloses a kind of "YW35 steel and its application", its chemical composition is: C 0.32~0.40, Si 0.30~0.50, Mn 1.1~1.3, P≤ 0.035, S≤0.035, Cu≤0.2, Nb 0.04~0.07, V 0.06~0.2, Mo 0.15~0.25

It is based on high manganese steel, in the case of reducing carbon content, adding appropriate amount of molybdenum, vanadium, niobium, in order to improve the low temperature performance of steel, but the processing technology of this invention is complicated, the cost is higher; Chinese patent (application number is 86103008), discloses a "medium-carbon air-cooled manganese-boron bainite steel", Chinese patent (application number is 86103009), discloses a "medium-high carbon air-cooled manganese-boron bainite steel", both invention patents Manganese and boron are used as alloy elements, but because of their high hardness, their tensile strength, plasticity and toughness are relatively poor, and their service life is not as good as that of railway rails; A "quasi-bainitic steel" is characterized in that its composition is composed of main alloying elements and at least one additional alloying element, and the weight percentage of the main alloying elements is: carbon C 0.04~1.3, Manganese Mn 1.0-3.5, carbide precipitation hindering elements 0.8-2.8, the weight percent composition of the additional alloying elements is: molybdenum Mo 0-0.6, boron B 0-0.005, chromium Cr 0-2.0, silicon Si 0-2.8, Aluminum Al 0-2.8 and other elements, in the technical features of its dependent claims, it is also pointed out that the element that hinders the precipitation of carbides is silicon or aluminum, and the main alloying elements and additional alloying elements of the invention are composed of silicon or aluminum, And the content range is confusing, so that people don't know whether the silicon or aluminum is the main alloying element or the additional alloying element. Since it is represented by "or", the subsequent dependent claims all include silicon and aluminum at the same time. The invention disclosed These technical features make it impossible for those skilled in the art to implement its technical solutions

Moreover, since its necessary technical feature is "composition of at least one additional alloying element", but the weight percent composition of the additional alloying elements all start from "0", if the minimum value "0" is taken, it means There may be no additional alloying elements, resulting in inconsistencies, which is one of the reasons why this technical solution cannot be implemented

Images