Steel plate for ultra-low temperature and high pressure service delivery pipe and manufacturing method thereof

Abstract

The invention discloses a steel plate for ultralow-temperature and high-pressure service delivery tubes, and its making method. The chemical components of the steel plate comprise 0.03-0.07wt% of C, 0-0.30wt% of Si, 1.5-1.9wt% of Mn, 0.015-0.06wt% of Al, 0.05-0.11wt% of Nb, 0.010-0.018wt% of Ti, 0.10-0.30wt% of Cr, 0.10-0.30wt% of Cu, 0.10-0.30wt% of Ni, 0-0.30wt% of Mo, 0-0.015wt% of P, 0-0.004wt% of S, 0-0.005wt% of N, and the balance of Fe and impurity elements, wherein a weight ratio of Ca / S is not smaller than 2, a weight ratio of Ti / N is not smaller than 4, the equivalent C amount Ceq of the steel plate is not greater than 0.43, and the crack sensitive index Pcm of the steel plate is not greater than 0.21. The yield strength and the tensile strength (Rm) of the steel plate made in the invention are not smaller than 500MPa and not smaller than 600MPa respectively, the steel plate has the advantages of good low temperature toughness, good crack cracking stopping performance, good weldability and low cost, and the making method has the advantages of simplicity and easy control, and is also suitable for making large ships, ocean engineering, bridges, high-rise buildings and important structural members.

Description

technical field [0001] This application relates to a hot-rolled thick-walled steel plate for large-diameter delivery pipes in ultra-low temperature and high-pressure service and its manufacturing method. Construction projects such as ships, ocean engineering, railway bridges and high-rise buildings. Background technique [0002] Energy is an important basis for the sustainable development of the national economy. Natural gas is a low-carbon mineral energy. Expanding its proportion in my country's energy structure has important practical significance for ensuring my country's energy and protecting the ecological environment. Pipeline transportation is an economical, efficient and environmentally friendly energy medium transportation method. With the rapid increase in the proportion of natural gas consumption in my country's primary energy consumption in the next ten years, the construction of natural gas pipeline networks will surely grow at a high speed. In order to meet th...

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Problems solved by technology

For example, the patent CN102277530B announced a "thickness ≥ 25mm for deep sea and its production method", its strength is controlled at X65 level, the Charpy V-shaped impact energy at -40 °C is ≥ 200J, and the shear area of ​​-20 °C drop hammer is ≥ 85 %, the mechanical properties cannot meet the design requirements of the above-mentioned engineering projects; and since it is a submarine pipeline, its width must also be less than 3200mm

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