Low-temperature-resistant and high-toughness Q345NQR2 hot-rolled steel strip with thickness being 10.0 to 14.0 mm and for railway carriage

Abstract

The invention discloses a low-temperature-resistant and high-toughness Q345NQR2 hot-rolled steel strip with the thickness being 10.0 to14.0 mm and for a railway carriage. Through the reasonable component design, the hot-rolled steel strip is prepared from the components of 0.20-0.40% of Ni, 0.020-0.030% of Ti, 0.26-0.36% of Cu, 0.45-0.55% of Cr and micro-alloy elements. Ferrite and pearlite are adopted as the micro-structure, the grain size is about 11 grades, and the low-temperature-resistant and high-toughness Q345NQR2 hot-rolled steel strip has the characteristics of high strength, good atmospheric corrosion resistance and low-temperature toughness and the like and suitable for structural steel for the railway carriage; and the mechanical property and process property of the low-temperature-resistant and high-toughness Q345NQR2 hot-rolled steel strip meet the requirements that the yield strength is 345 to 480 MPa, the tensile strength is 480 to 580 MPa, the percentage elongation A is larger than or equal to 24%, the cold bend d is equal to 2a, and the impact value of minus 40 DEG C is larger than or equal to 27 J.

Description

technical field [0001] The invention relates to the technical field of thick-gauge high-strength steel production, especially with high strength, high corrosion resistance, low-temperature impact toughness and high welding performance, and is mainly used for atmospheric corrosion resistance of railway vehicles, bridges, towers, etc. under corrosion-resistant conditions. structural steel. In particular, it relates to a 10.0-14.0mm thick low-temperature-resistant high-toughness Q345NQR2 hot-rolled steel strip for railway carriages. Background technique [0002] With the continuous development of my country's national economic construction, atmospheric corrosion-resistant steel for railway vehicles has been widely used in railway vehicles. my country began to develop weathering steel in the 1960s. In the 1980s, it started to tackle key problems of weathering steel and put it into mass production. In the early 1990s, a batch of weathering steels were developed, including Cu, P,...

AI Technical Summary

Problems solved by technology

[0005] Wang Jun et al. (Wang Jun et al., Development of high-strength steel plates for Q345NQR2 railways, Steel Rolling, Issue 3, 2019) studied the effect of incipient cooling temperature on the microstructure of Q345NQR2 steels for railways with low yield ratio through low-carbon and microalloy chemical composition design. Influenced by the performance and performance, the Q345NQR2 steel plate with low yield ratio for railway vehicles was developed on the medium and heavy plate production line, but the production performance process control parameters of 10.0-14.0mm thick steel strip products were not involved in the article

[0006] In short, the production and preparation methods of Q345NQR2 railway carriage steel involved in the above-mentioned documents failed to clearly study and explain the steel strip with a thickness of 10.0-14.0 mm, and did not study the technical problem of low low-temperature impact performance of products of this specification.

Images