Highly corrosion-resistant, high strength, A1-containing weathering steel plate and process of manufacturing same

Patent metadata

Field	Value
Publication number	US-10760149-B2
Application number	US-201314762592-A
Country	US
Kind code	B2
Filing date	Dec 24, 2013
Priority date	Jan 24, 2013
Publication date	Sep 1, 2020
Grant date	Sep 1, 2020

Abstract

The invention provides a highly corrosion-resistant, high strength, Al-containing weathering steel plate, wherein the chemical composition comprises in weight percentages (wt %) of: C: 0.02-0.07%, Si: 0.2-1.0%, Mn: 0.2-2.2%, P≤0.01%, S≤0.006%, Cu: 0.2-0.5%, Cr: 0.5-3.5%, Ni: 0.2-1.2%, Al: 0.4-4.0%, N≤0.005%; selectively added one or more of Nb: 0.01-0.06%, Ti: 0.01-0.10%, V: 0.02-0.10%; the balance of Fe and unavoidable impurities, wherein Al/Cr is 0.5-8.0. The steel plate has a yield strength of 350-500 MPa, an elongation of 20% or more, a relative corrosion rate of 27% or less and a good impact toughness and a low yield ratio. The present application also provides a method for manufacturing the weathering steel plate.

First claim

What is claimed is:

1. A highly corrosion-resistant, high strength, Al-containing weathering steel plate, comprising the following chemical elements in weight percentages (wt %) of: C: 0.02-0.07%, Si: 0.2-1.0%, Mn: 0.2-2%, P≤0.01%, S≤0.006%, Cu: 0.2-0.5%, Cr: 0.7-2.4%, Ni: 0.2-1.2%, Al: 3.0-3.5%, N≤0.005%, the balance of Fe and unavoidable impurities, wherein Al/Cr is 1.25-4.75; and the steel plate has a yield strength of 350-500 MPa, a relative corrosion rate of 19.9% or less, a Charpy full-sample impact energy of 60 J or more at −40° C., and an elongation of 20% or more.

2. The highly corrosion-resistant, high strength, Al-containing weathering steel plate of claim 1 , further comprising one or more of Nb, Ti and V, wherein Nb: 0.01-0.06%, Ti: 0.01-0.10%, V: 0.02-0.10%, based on weight percentage.

3. A process of manufacturing a highly corrosion-resistant, high strength, Al-containing weathering steel plate, comprising the following steps:
1) Smelting, external refining, continuous casting:
By smelting, external refining and continuous casting, a slab is formed from the following chemical components in weight percentages (wt %): C: 0.02-0.07%, Si: 0.2-1.0%, Mn: 0.2-2.2%, P≤0.01%, S≤0.006%, Cu: 0.2-0.5%, Cr: 0.7-2.4%, Ni: 0.2-1.2%, Al: 3.0-3.5%, N≤0.005%, the balance of Fe and unavoidable impurities, wherein Al/Cr is 1.25-4.75;
2) Slab heating: the slab obtained in step 1) is heated at a temperature of 1220° C. or above;
3) Rolling: the rolling process is controlled by two stages of rough rolling and finish rolling, and the end rolling temperature of the finish rolling is 720-800° C.;
4) Cooling: the rolled steel plate is cooled at a cooling rate of 10-40° C./s;
5) Coiling, finishing: the steel plate is controlled to be coiled at a temperature in the range of 460−520° C., and then cooled to room temperature, followed by finishing to give the highly corrosion-resistant, high strength, Al-containing weathering steel plate wherein the steel plate obtained has a yield strength of 350-500 Mpa, a relative corrosion rate of 19.9% or less, a Charpy full-sample impact energy of 60 J or more at −40° C., and an elongation of 20% or more.

4. The process of manufacturing a highly corrosion-resistant, high strength, Al-containing weathering steel plate according to claim 3 , wherein the chemical components of the molten steel further comprises one or more of Nb, Ti and V, wherein Nb: 0.01-0.06%, Ti: 0.01-0.10%, V: 0.02-0.10%, based on weight percentage.

Assignees

• Baoshan Iron & Steel

Inventors

• Song Fengming
• Wen Donghui
• Li Zigang
• Hu Xiaoping
• Yang Ana
• Li Jianye

Classifications

• Y02P10/20

  Recycling · CPC title

• C22C33/04 Primary

  by melting · CPC title

• C21D2211/005

  Ferrite · CPC title

• C21D2211/002

  Bainite · CPC title

• C22C38/02

  containing silicon · CPC title