A fire-resistant steel for welded structures with excellent creep rupture performance at 700°C high temperature and production method thereof

Abstract

The invention discloses a fire-resistant steel for welded structures with excellent 700°C high-temperature creep rupture performance and a production method thereof. The fire-resistant steel contains the following chemical components in mass fractions: C: 0.02-0.08%, Si: 0.05-0.20 %, Mn: 0.80~1.25%, P≤0.003%, S≤0.002%, Mo: 0.08~0.20%, Nb: 0.052~0.12%, Ti: 0.007~0.030%, Y: 0.015~0.072%, [N] : 10~20×10 ‑4 %, [O]≤32×10 ‑4 %, the balance is Fe and unavoidable impurities, and the above chemical composition must also meet the formula: 7.26%≤30C+5Mn+6Mo≤8.05%; the present invention only adds a small amount of Mo, does not add precious metals such as Cr and Ni, and does not need to be carried out The complex heat treatment process has the advantages of low cost, simple manufacturing process and short production cycle, and can be implemented on a large scale in various metallurgical enterprises; the steel plate produced by the method of the present invention has excellent fire resistance, high temperature creep rupture performance and welding performance And other characteristics, can be widely used in various large-scale steel structure projects that require fire resistance.

Description

technical field [0001] The invention relates to the technical field of low-alloy steel manufacturing, in particular to a fire-resistant steel for welded structures with excellent 700°C high-temperature creep fracture performance and a production method thereof. Background technique [0002] In addition to conventional indicators, steel used in large-scale steel structures such as buildings, bridges, factories and mines also requires excellent fire resistance and welding performance. The refractory performance requires that the yield strength of the steel at 600°C is not lower than 2 / 3 of the yield strength at room temperature. The use of refractory steel can reduce the thickness of the refractory coating or even use it bare, reducing construction costs and maintenance costs. In the event of a fire , due to the long-lasting steel at high temperatures, casualties and property losses can be minimized. Due to the addition of more precious alloys such as Mo and Cr that are not c...

AI Technical Summary

Problems solved by technology

[0006] Patent Nos. 201110080774.6, 201110247615.0 and 200910045146.7 Chinese invention patents respectively disclose a low-cost, high-strength, high-toughness anti-seismic fire-resistant steel and its preparation process, a fire-resistant and anti-seismic construction steel, and a high-strength, high-toughness, low-yield ratio fire-resistant steel and Its manufacturing method, but the three invention patents only require 0°C impact toughness, and do not require high temperature creep rupture performance and welding performance

Images