Railway steel plate with high strength and low yield ratio and good toughness and manufacturing method thereof

Abstract

The invention discloses a railway steel plate with high strength and low yield ratio and good toughness and a manufacturing method thereof. The steel plate is prepared from the following components: C, Si, Mn, P, S, Ni, V, Nb, Ti, N and the balance of Fe and impurities, wherein the element contents of the components satisfy the following relation: Nb+V+Ti is less than or equal to 0.11%. Accordingto the manufacturing method, the adding variety and the adding content of alloy elements are reasonably set, the intensifying effect of V and Ti elements and the grain refining effect of Ni and Nb elements are fully achieved, and then a tempering heat treatment process is added after a TMCP (Thermal Mechanical Control Processing) technique, so that steel structures include ferrite, pearlite and asmall quantity of bainite structures so as to enhance the low-temperature toughness of steel. The thickness of the steel plate provided by the invention is 10 to 30 mm, the yield strength ReL of the steel plate at room temperature is greater than or equal to 420 MPa, the tensile strength is 600 to 720 MPa, the low yield ratio is less than or equal to 0.75%, the elongation A is greater than or equal to 20%, the impact work KV2 at the temperature of -46 DEG C is greater than or equal to 130 J, the alloy variety is small, the alloy dosage is low, the production cost is low, and economic benefitsand social benefits are good.

Description

technical field [0001] The invention relates to the technical field of steel manufacture, in particular to a steel plate for railways with high strength, low yield strength and excellent toughness and a manufacturing method thereof. Background technique [0002] With the rapid development of my country's economy, in freight and energy transportation, railway transportation has large transportation capacity, large single-vehicle loading capacity, high speed, and is less affected by climate and natural conditions. At the same time, it can conveniently realize piggyback transportation and container transportation. And the advantages of multimodal transport play an important role. As of the end of 2018, the total mileage of China's railways has reached 131,000 kilometers, and there is a large demand for railway steel. Therefore, the development of such steel plates has become an inevitable demand to adapt to the rapid development of my country's railway transportation. [0003] ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to propose a steel plate for railways with high strength, low yield strength and excellent toughness and a manufacturing method thereof, so as to solve the problem that the low-temperature toughness and tensile strength of steel plates for railway vehicles are difficult to meet the requirements for use in alpine regions. The thickness specification of the ship plate steel is 10~30mm, the yield strength ReL at room temperature is ≥420MPa, the tensile strength is 600~720MPa, the low yield ratio is ≤0.75%, the elongation A is ≥20%, and the impact energy is KV at -46℃ 2 ≥130J, steel structure used for railway steel in high and cold areas

Images