Fire resistant and weather resistant steel with yield strength larger than or equal 690 MPa and used for welding structure and production method thereof

Abstract

The invention belongs to the field of low alloy steel manufacturing, and particularly provides fire resistant and weather resistant steel with yield strength larger than or equal 690 MPa and used fora welding structure and a production method thereof. The steel comprises, by weight percent, 0.027 to 0.086% of C, 0.03 to 0.12% of Si, 1.65 to 2.12% of Mn, not larger than 0.003% of P, not larger than 0.002% of S, 0.21 to 0.40% of Mo, 0.12 to 0.25% of Cr, 0.12 to 0.28% of Cu, 0.21 to 0.43% of Ni, 0.052 to 0.095% of Nb, 0.078 to 0.122% of V, 0.007 to 0.018% of Ti, 0.0023 to 0.0072% of Zr, 0.010 to0.025% of Ta, 0.0012 to 0.0047% of N, 0.0034 to 0.0052% of O, and the balance Fe and inevitable impurities. Meanwhile, (2Zr+Ta)/O is equal to 5.28 to 6.31, 7C+3Mn is equal to 5.32 to 6.67%, Pcm is equal to C+Si/30+(Mn+Cr+Cu)/20+Ni/60+Mo/15+V/10+5B smaller than or equal to 0.22%, and a product produced through the production method has the high strength toughness, excellent fire resistance and weather resistance(obviously superior to CortenB steel) and lamellar tearing resistance.

Description

technical field [0001] The invention belongs to the field of low-alloy steel manufacturing, and specifically provides a fire-resistant and weather-resistant steel for welded structures with a yield strength ≥ 690 MPa and a production method thereof. Background technique [0002] With the continuous development of iron and steel metallurgy technology, structural parts such as columns and beams of steel structures have put forward new requirements for steel plate strength, fire and disaster resistance, corrosion resistance, and earthquake resistance, while ordinary steel structures are poor in the construction industry. The ability to resist fire, disaster and corrosion is facing a severe test. In recent years, metallurgists at home and abroad have actively carried out research on fire-resistant, weather-resistant, and earthquake-resistant steels. Fire-resistant and weather-resistant steel can not only make up for the shortcomings of ordinary steel structures with poor fire re...

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Problems solved by technology

However, the welding performance and corrosion resi

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