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Ferritic stainless steel sheet for water heater excellent in corrosion resistance at welded part and steel sheet toughness

A stainless steel plate and water heater technology, applied in heat treatment furnaces, heat treatment equipment, furnace types, etc., can solve problems such as material corrosion, and achieve the effects of improved corrosion resistance, improved corrosion resistance, and excellent toughness.

Active Publication Date: 2009-11-11
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] However, when ferritic stainless steel is used as a material for electric water heaters, etc., since running water contains residual chlorine for sanitation requirements (sanitary requirement), there is oxidation by the residual chlorine ( The problem of material corrosion caused by oxygenbehaviour)

Method used

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  • Ferritic stainless steel sheet for water heater excellent in corrosion resistance at welded part and steel sheet toughness
  • Ferritic stainless steel sheet for water heater excellent in corrosion resistance at welded part and steel sheet toughness
  • Ferritic stainless steel sheet for water heater excellent in corrosion resistance at welded part and steel sheet toughness

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Embodiment 1

[0084] Hereinafter, the present invention will be described in more detail based on examples.

[0085] The steel (steel numbers 1 to 17 are examples of the present invention, 18 to 22, A and B are comparative examples, and 23 and 24 are steels composed of components shown in Table 1 are smelted with a 50 kg small scale vacuum melting furnace). Existing example). After heating these steel ingots to 1050-1250°C, they are hot-rolled at a finishing temperature of 750-950°C and a coiling temperature of 650-850°C. rolling plate.

[0086] First, the toughness of the obtained hot-rolled sheet was investigated at this time. In the study, the shape of the test piece was No. 4 of JIS Z2202, and the V-notch was processed so that the direction of the V-notch was perpendicular to the rolling direction (C direction), and the pendulum impact was performed. test. The toughness was evaluated by observing the fracture (fracture cross section) with a microscope (microscope) and SEM (scanning ...

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Abstract

Disclosed is a ferritic stainless steel sheet for a water heater, which shows excellent corrosion resistance at a welded part and has an excellent steel sheet toughness. Specifically disclosed is a ferritic stainless steel sheet for a water heater, which comprises the following components (by mass): C: 0.020% or less, Si: 0.30-1.00%, Mn: 1.00% or less, P: 0.040% or less, S: 0.010% or less, Cr: 20.0-28.0%, Ni: 0.6% or less, Al: 0.03-0.15%, N: 0.020% or less, O: 0.0020-0.0150%, Mo: 0.3-1.5%, Nb: 0.25-0.60%, and Ti: 0.05% or less, with the remainder being Fe and unavoidable impurities, and which satisfies the requirements expressed by the following formulae (1) and (2). 25 <= Cr+3.3Mo <= 30 (1) 0.35 <= Si+Al <= 0.85 (2), wherein 'Cr', 'Mo', 'Si' and 'Al' represent the contents (expressed by mass%) of Cr, Mo, Si and Al, respectively.

Description

technical field [0001] The present invention relates to a ferritic stainless steel sheet for water heaters having excellent corrosion resistance, especially corrosion resistance of welds, and steel sheet toughness. Background technique [0002] Ferritic stainless steels such as JIS (Japanese Industrial Standards)-SUS444 are characterized by lower sensitivity to stress corrosion cracking (SCC: stress corrosion cracking) than austenitic stainless steels, and are therefore used as Used as materials for electric water heaters, etc. [0003] However, when ferritic stainless steel is used as a material for electric water heaters, etc., since residual chlorine is contained in running water for sanitary requirements (sanitary requirement), there is an oxidation effect caused by the residual chlorine ( The problem of material corrosion caused by oxygen behavior). In particular, the corrosion resistance of welded parts (weld metal, welded heat affected zone) often becomes a problem....

Claims

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Application Information

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IPC IPC(8): C22C38/00C21D9/46C22C38/50
CPCC21D9/46C21D8/0236C22C38/02C21D8/0273C22C38/04C21D2211/001C22C38/22C22C38/44C22C38/50C22C38/46C22C38/06C22C38/26C22C38/48C21D6/002C21D8/0226C22C38/001
Inventor 福田国夫船川义正冈田修二笠茂利广小堀克浩宇城工石井知洋
Owner JFE STEEL CORP
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