Ultra-strength, high toughness and low yield ratio steel and steel plate and manufacturing method thereof

Abstract

The invention provides ultra-strength, high toughness and low yield ratio steel, which comprises the following chemical components: 0.05 to 0.12 weight percent of C, 0.15 to 0.50 weight percent of Si,1.0 to 1.5 weight percent of Mn, less than or equal to 0.025 weight percent of P, less than or equal to 0.015 weight percent of S, 0.20 to 0.50 weight percent of Cu, less than or equal to 0.25 weightpercent of Ni, 0.015 to 0.05 weight percent of Nb, 0.015 to 0.045 weight percent of V, 0.010 to 0.050 weight percent of Ti, less than or equal to 0.55 weight percent of Cr, less than or equal to 0.30weight percent of Mo, 0.015 to 0.05 weight percent of Al and the balance of Fe and inevitable impurities. The invention also provides a steel plate manufactured by using the ultra-strength, high toughness and low yield ratio steel and a manufacturing method thereof. The steel plate has excellent mechanical property, has a yield strength of more than or equal to 460 Pa and a yield ratio of less than or equal to 0.80. Moreover, the steel plate has good low-temperature impact toughness and weldability, and is suitable for high steel-structure buildings and other large-scale steel structure fields with low yield ratio requirements.

Description

technical field [0001] The present invention relates to iron and steel materials, in particular, the present invention relates to a high-strength, high-toughness, low-yield ratio steel, a steel plate and a manufacturing method thereof Background technique [0002] With the increase of steel production in my country, steel structure buildings have also developed rapidly. At present, domestic high-strength steel plates such as Q420 and Q460 are mostly delivered in normalized state, and the yield ratio of steel plates is usually greater than 0.80. Due to the continuous development of modern buildings in the direction of large space, large span and super high-rise buildings, the requirements for steel used in building structures are getting higher and higher, not only requiring high strength, high toughness and good weldability, but also in order to meet the earthquake resistance of steel structure buildings. The function of earthquake resistance puts forward the requirement of ...

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Problems solved by technology

The steel process of this invention is relatively simple and does not require heat treatment, but its main disadvantage is that the alloy content is too high, so the production cost is high

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