Soldering not quenching and tempering steel plate in high intensity by large line energy, and manufacturing method

Abstract

This invention relates to a method for producing non-quenched and tempered high-strength steel plate suitable for high heat input welding. The chemical compositions are: C 0.01-0.25 wt.%, Si 0.05-0.5 wt.%, Mn 0.5-1.8 wt.%, Als 0.001-0.06 wt.%, Nb 0.01-0.08 wt.%, Ti 0.01-0.08 wt.%, N 0.002-0.012 wt.%, B 0.0001-0.003 wt.%, P less than 0.015 wt.%, S less than 0.015 wt.%, Fe and impurities. The method comprises: steelmaking and refining molten iron, waste steel or their mixture in a converter or electric arc furnace so that the oxygen content is 10-600 ppm, performing deoxidation with Fe-Ti alloy or metal Ti, performing final deoxidation with Al wire, adding B, continuously casting, and hot-rolling. The obtained steel plate is suitable for 150-600 kJ / cm high heat input welding, and has such advantages as high welding quality, high production efficiency, and saved energy.

Description

Technical field: [0001] The invention belongs to the technical field of low-alloy high-strength steel. In particular, it relates to a non-quenched and tempered low-alloy high-strength steel welded with large heat input and a manufacturing method thereof. Background technique [0002] Low-alloy high-strength steel is widely used in infrastructure, important facilities and large buildings such as buildings, bridges, pressure vessels, storage tanks, pipelines and ships. Since the end of the 1970s, in many fields such as shipbuilding, petroleum, and urban construction, engineering structures have increasingly developed in the direction of large-scale and high-parameters. [0003] In recent years, in order to improve the welding efficiency of large-scale engineering structures and ensure the safety and reliability of their use, single-sided submerged arc welding, gas-electric welding, electroslag welding and other high-energy welding technologies with high welding efficiency hav...

AI Technical Summary

Problems solved by technology

[0007] (2) There is no clear regulation on the content of oxygen, so it is difficult to improve product quality and welding line energy;

[0008] (3) Si content is higher, because higher content of Si will promote the formation of M / A and reduce the toughness of HAZ;

[0009] (4) Contain expensive metal vanadium, which increases the cost of the product;

[0010] (5) Some are produced by quenching and tempering process, so the production process is complicated, there are many links, and the production cost is high. Due to the use of quenching and tempering process, the carbon content is generally higher than that of non-quenching and tempering process, which is not conducive to the resistance to larger Line energy welding and realization of controlled rolling and controlled cooling and mechanical heat treatment process (TMCP);

[0011] (6) Steel contains rare earth elements, rare earth elements are very active elements, not easy to control, and easy to pollute molten steel, which is not conducive to the improvement of product quality