High-corrosion resistance high-toughness high-chromium ferrite stainless steel plate and manufacturing method thereof

Abstract

The invention discloses a high-corrosion resistance high-toughness high-chromium ferrite stainless steel plate and a manufacturing method thereof. The high-corrosion resistance high-toughness high-chromium ferrite stainless steel plate comprises, by weight, 0.005 to 0.015% of C, 0.005 to 0.020% of N, 0.2 to 0.5% of Si, 0.2 to 0.5% of Mn, less than or equal to 0.035% of P, less than or equal to 0.010% of S, 25 to 28% of Cr, less than or equal to 4.0% of Ni, 2.0 to 4.0% of Mo, 0.1 to 0.3% of V, 0.10 to 0.30% of Ti, 0.2 to 0.4% of Nb, less than or equal to 0.005% of Al, less than or equal to 0.005% of O, and the balance Fe and unavoidable impurities, wherein based on Cr content, Mo content, Ti content, Nb content, C content and N content respectively represented by Cr, Mo, Ti, Nb, C and N, Cr+3.3*Mo is greater than or equal to 35% and Ti+Nb is greater than or equal to 16(C+N). The high-corrosion resistance high-toughness high-chromium ferrite stainless steel plate has a ductile-brittle transition temperature below -40 DEG C, pitting potential above 1000mv, a critical pitting temperature above 70 DEG C, a corrosion rate below 0.2g / m<2>h in boiling hydrochloric acid having a concentration of 1wt%, yield strength above 380MPa, tensile strength above 520MPa, an elongation rate A50mm above 25% and Vickers hardness of 180 to 220, and can be used in various harsh environments.

Description

technical field [0001] The invention relates to a high-corrosion-resistant, high-toughness, high-chromium ferritic stainless steel plate and a manufacturing method thereof. The ductile-brittle transition temperature of the steel is below -40°C, the pitting potential is above 1000mv, and the critical pitting temperature is 70°C Above, the corrosion rate is 0.2g / m in boiling hydrochloric acid with a concentration of 1% by mass 2 h or less, the yield strength is above 380MPa, the tensile strength is above 520MPa, the elongation A50mm is above 25%, and the Vickers hardness is 180-220. Background technique [0002] Ferritic stainless steel is a stainless steel with a chromium content of 11-30%, a body-centered cubic crystal structure, and a ferrite structure in use. In addition to general corrosion resistance, ferritic stainless steel also has good local corrosion resistance such as chloride pitting corrosion, stress corrosion and crevice corrosion. In addition, ferritic stainl...

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Problems solved by technology

Chinese patent CN102392189A added Mo, Ni to improve corrosion resistance, and adopted Nb, Ti dual stabilization, but its Ni content was low, and V was not added, and low temperature toughness was insufficient; Among the Chinese patent CN101381842, Cr content was low, added A small amount of Cu, but does not contain Mo, Ni, V, and its corrosion resistance is low; Chinese patent CN101525724 only contains a very small amount of Mo, does not contain Ni and stabilizing elements Nb and Ti; Chinese patent CN201006392 uses Ti single stabilization, adding Cu and rare earth elements are added, Ni, Nb and V are not added, and impurity elements such as O are not restricted; Japanese patents JP05320764A and JP08253813A use higher Cr content to improve corrosion resistance, but do not add Ni and V to improve Low temperature toughness; although Ni is added in European patent EP0097254 (A2), a large amount of Cu and Zr are added at the same time, and V is not added to improve toughness

[0005] Through the comparative analysis of the above patents, it can be seen that the high-chromium ferritic stainless steel in the prior art cannot fully meet the current use and manufacturing requirements, and has poor corrosion resistance or poor low-temperature toughness. Therefore, it is necessary to develop a high-corrosion, high-low temperature stainless steel Tough high chromium ferritic stainless steel

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