Soldering boat deck steel in high intensity by large line energy, and manufacturing method

Abstract

This invention relates to a method for producing high-strength ship plate steel suitable for high heat input welding. The chemical compositions of the ship plate steel are: C 0.01-0.18 wt.%, Si 0.05-0.4 wt.%, Mn 1.0-1.8 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 0.0001-0.0030 wt.%, one or more of Ca, Mg and Zr 0.0001-0.030 wt.%, P less than 0.015 wt.%, S less than 0.010 wt.%, Fe and impurities. The method comprises: keeping the oxygen content in the molten steel at 10-600 ppm, performing deoxidation with Fe-Ti alloy or metal Ti after steelmaking, adding one or more of Ca, Mg and Zr, performing final deoxidation with Al wire, adding B, casting, homogenizing, rolling, relaxing, and cooling online. The obtained ship plate steel has such advantages as simple chemical compositions, simple process, and high heat input welding, and is suitable for producing ships.

Description

Technical field: [0001] The invention belongs to the technical field of high-strength steel. In particular, it relates to a high-strength ship plate steel capable of welding against large heat input (150-600kJ / cm) and a manufacturing method thereof. Background technique [0002] In recent years, with the growth of long-distance transportation in the shipbuilding industry, the large-scale container shipping has developed rapidly, from the original 6000TEU (converted by volume per 20 feet) to 8000TEU, and is currently moving to 10000TEU super Large ship development. The steel used in large container ships requires higher strength and thickness than traditional ship plates. The maximum thickness of steel plates with a yield strength (Ys) of 390MPa has reached more than 65mm, while thick plates need to be welded by traditional welding methods. For multi-layer welding, the construction efficiency is significantly reduced. The actual welding line energy of gas-electric vertical ...

AI Technical Summary

Problems solved by technology

[0007] (2) There is no clear regulation on the content of oxygen

Such as "Large input energy and low welding crack sensitivity series steel and its production method" (ZL 02115877.0), "High-performance fire-resistant and weather-resistant construction steel and its production method" (ZL01133562.9), "Non-quenched and tempered Tough low-temperature steel and its production method" (ZL 01128316.5), steel for high-toughness and corrosion-resistant zinc solution for high heat input welding and its production method (01128476.5), "a thick steel plate capable of high heat input welding and its manufacturing method" (CN 200510023216.0), "Steel for pressure pipes of hydropower stations welded with large heat input and its production method" (CN200510019165.4), "ultra-high-strength thick steel plate capable of welding with large heat input and its manufacturing method" (ZL 200410017255.5) and other patented technologies, which are difficult to improve Product Quality and Welding Heat

[0008] (3) High Si content

A higher content of Si will promote the formation of M / A and reduce the toughness of HAZ

[0009] (4) Contains expensive metal vanadium

Rare earth elements are very active elements, not easy to control, and easy to pollute molten steel, which is not good for steel quality