Steel plate with obdurability and strong plasticity and manufacturing method thereof

Abstract

The invention provides an HT780 steel plate and a manufacturing method thereof. The HT780 steel plate comprises the following components by weight percentage: 0.050 to 0.090 of C, less than or equal to 0.15 of Si, 1.00 to 1.50 of Mn, less than or equal to 0.013 of P, less than or equal to 0.003 of S, 0.40 to 0.80 of Cr, 0.25 to 0.55 of Cu, 0.40 to 0.90 of Ni, 0.25 to 0.55 of Mo, 0.040 to 0.060 ofAl, 0.005 to 0.011 of Ti, 0.015 to 0.045 of V, less than or equal to 0.0040 of N, 0.001 to 0.005 of Ca, 0.006 to 0.0013 of B and the balance of Fe and inevitable impurities. The excellent low-temperature flexibility, high strength and extensibility and excellent weldability can be achieved by the design and the process.

Description

technical field [0001] The invention relates to a HT780 steel plate and a manufacturing method thereof, in particular, the invention relates to an HT780 steel plate with excellent strength, toughness, and strong plasticity matching and a manufacturing method thereof. Background technique [0002] As we all know, low-carbon (high-strength) low-alloy steel is one of the most important engineering structural materials, widely used in oil and gas pipelines, offshore platforms, shipbuilding, bridge structures, boiler containers, building structures, automobile industry, railway transportation and machinery manufacturing middle. The properties of low-carbon (high-strength) low-alloy steels depend on their chemical composition and manufacturing process, and their most important properties—strength, toughness, and weldability—ultimately depend on the microstructural state of the finished steel. With the continuous development of science and technology, people put forward higher re...

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Problems solved by technology

However, a large number of existing patent documents only explain how to realize the strength and low-temperature toughness of the base metal steel plate, improve the weldability of the steel plate, and obtain excellent low-temperature toughness of the welding heat-affected zone HAZ. At the same time as the tensile strength, the tensile elongation of the steel plate is improved (Zhao 63-93845, Zhao 63-79921, Zhao 60-258410, TPP 4-285119, TPP 4-308035, Ping 3-264614, Ping 2 -250917, Ping 4-143246, US Patents US 4855106, US 5183198, US 4137104)

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