420MPa-grade weather-resistant structural steel with impact energy of more than 150J at-80 DEG C and production method of 420MPa-grade weather-resistant structural steel

Abstract

The invention discloses 420MPa-grade weather-resistant structural steel with impact energy greater than 150J at-80 DEG C. The 420MPa-grade weather-resistant structural steel comprises the following chemical components in percentage by weight: 0.07 to 0.09 percent of C, 0.20 to 0.30 percent of Si, 1.20 to 1.40 percent of Mn, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S, 0.04 to 0.05 percent of Nb, 0.012 to 0.020 percent of Ti, 0.52 to 0.60 percent of Cr, 0.32 to 0.39 percent of Ni, 0.35 to 0.45 percent of Cu, 0.017 to 0.027 percent of Als and 0.0004 to 0.0015 percent of rare earth Ce. The invention further discloses a production method. The 420MPa-grade weather-proof structural steel plate obtained by the invention has the impact energy of more than 150J at the temperature of-80 DEG C, low yield ratio, good corrosion resistance and welding performance, and can be used for construction of polar region steel structures.

Description

technical field [0001] The invention relates to microalloyed steel, in particular to a 420MPa grade weathering structural steel with impact energy greater than 150J at -80°C and a production method thereof. Background technique [0002] The Antarctic and Arctic environments are harsh all year round, and the temperature is in the range of -40°C to -60°C. It is difficult to construct steel structure projects in this area, and the performance requirements of steel are relatively high, especially the steel plate is required to have excellent low-temperature impact toughness, cold-brittle transition The temperature should be lower than -60 ℃ to ensure the safety of steel structure engineering. In the actual steel structure engineering design, if the ambient temperature is -60℃, the impact toughness of the steel plate at -80℃ should reach a certain level to improve the safety factor of the steel structure. At present, the impact toughness quality grade of general structural steel...

AI Technical Summary

Problems solved by technology

The first disadvantage is that the strength level of the steel plate is low, which is only suitable for steel used in marine engineering

Second, the cooling temperature of the steel plate is low, and the shape control is difficult, which is not conducive to mass production

The first disadvantage is that the steel plate rolling temperature is low, the reduction rate is high, and the requirements for equipment capacity are strict, which is not conducive to stable production. It is suitable for hull steel

Second, the weather resistance of the steel plate is not good

The first disadvantage is that the yield strength of the steel plate is 355MPa, and the strength level is low

Second, the service temperature is -60°C, which cannot meet the steel requirements for -80°C environment

Images