Ferritic stainless steel sheet having excellent brazability, heat exchanger, ferritic stainless steel sheet for heat exchangers, ferritic stainless steel, ferritic stainless steel for members of fuel supply systems, and member of fuel supply system

一种不锈钢板、热交换器的技术，应用在热交换器固定、热交换设备、具有防腐蚀措施的燃料喷射装置等方向，能够解决未提出耐腐蚀性和钎焊性不锈钢等问题，达到耐腐蚀性优良、优良强度、钎焊性优良的效果

Active Publication Date: 2015-10-28
NIPPON STEEL STAINLESS STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Stainless steel with both corrosion resistance and brazability has not been proposed before

Method used

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  • Ferritic stainless steel sheet having excellent brazability, heat exchanger, ferritic stainless steel sheet for heat exchangers, ferritic stainless steel, ferritic stainless steel for members of fuel supply systems, and member of fuel supply system
  • Ferritic stainless steel sheet having excellent brazability, heat exchanger, ferritic stainless steel sheet for heat exchangers, ferritic stainless steel, ferritic stainless steel for members of fuel supply systems, and member of fuel supply system
  • Ferritic stainless steel sheet having excellent brazability, heat exchanger, ferritic stainless steel sheet for heat exchangers, ferritic stainless steel, ferritic stainless steel for members of fuel supply systems, and member of fuel supply system

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Experimental program
Comparison scheme
Effect test

no. 1 Embodiment approach

[0066] The object of this embodiment is a ferritic stainless steel plate used as a raw material of a member obtained by brazing using a nickel brazing filler metal or a copper brazing filler metal. Brazing is performed at 950-1200°C in vacuum or in a hydrogen atmosphere. At this time, argon gas, nitrogen gas, or the like may be used in combination as a controlled atmosphere or for substitution. In brazing, the brazing material wets the master batch (raw material) and fills gaps, thereby joining the master batch. When an oxide film exists on the surface of the raw material, wettability becomes difficult and brazeability is hindered.

[0067] A Cr (Fe, Cr)-rich oxide film is formed on the surface of the stainless steel plate, thereby showing excellent corrosion resistance. In order to ensure wettability, it is necessary to remove this coating, and to restore the coating, it is brazed under conditions of a vacuum degree or a low dew point. Specifically, the brazing of stainles...

no. 2 Embodiment approach

[0146] First, brazing properties will be described. This embodiment is aimed at the brazing of members made of stainless steel using nickel brazing filler metal or copper brazing filler metal. Brazing wets members by brazing and fills and joins gaps between members. When an oxide film exists on the surface of the stainless steel constituting the member to be brazed, the member becomes difficult to wet and brazeability is hindered.

[0147] A Cr (Fe, Cr)-rich oxide film (passive film) is formed on the surface of stainless steel, thereby showing excellent corrosion resistance. In order to ensure the wettability of stainless steel, it is necessary to reduce and remove this oxide film during brazing. When brazing a stainless steel plate, it is usually kept at the brazing temperature for about 10 to 30 minutes. How to reduce the film formed on the surface of the stainless steel within this limited time has a great influence on the brazeability.

[0148] In view of this backgrou...

Embodiment 1

[0236] 30 kg of molten steel having the chemical composition shown in Table 1 was melted in a vacuum melting furnace to produce a 17 kg flat steel ingot. Next, the steel ingot was hot-rolled at a heating temperature of 1200° C. to a thickness of 4.5 mm. The hot-rolled sheet was annealed at 950° C., and then the scale was removed by aluminum shot blasting, and the hot-rolled sheet was cold-rolled to a sheet thickness of 1 mm. After that, finishing annealing is performed, and scale is removed by salt method and immersion in nitric acid-hydrofluoric acid.

[0237] The finishing annealing temperature was the temperature shown in Table 1, and the holding time was 1 minute.

[0238] As the salt method, a method of heating a commercially available descaling alkali salt mainly composed of NaOH and immersing the steel sheet in the alkali salt was used. The heating temperature was set to the temperature shown in Table 1 and the immersion time was 5 seconds.

[0239] In the impregnatio...

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Abstract

One embodiment of a ferritic stainless steel sheet contains, in mass%, 0.03% or less of C, 0.05% or less of N, 1% or less of Si, 1.2% or less of Mn, 14 to 28% inclusive of Cr, 8(C+N) to 0.8% inclusive of Nb, 0.1% or less of Al and a remainder made up by Fe and unavoidable impurities, and has, formed on the surface thereof, a coating film that satisfies formula (1). df×Crf+5(Sif+3Alf) ≤ 2.0 ···(formula (1)) In the formula, df represents the thickness (nm) of the coating film; Crf represents the Cr cation fraction in the coating film; Sif represents the Si cation fraction in the coating film; and Alf represents an Al cation fraction in the coating film.

Description

technical field [0001] The present invention relates to a ferritic stainless steel plate used as a raw material of members assembled by brazing, and a heat exchanger and a fuel supply system component using the stainless steel plate. [0002] This application claims priority based on Japanese Patent Application No. 2013-071740 filed in Japan on March 29, 2013 and Japanese Patent Application No. 2013-148951 filed in Japan on July 17, 2013, the contents of which are incorporated herein. Background technique [0003] In recent years, as awareness of environmental problems has increased in the automotive field, efforts to reduce emissions of carbon dioxide gas have also advanced while exhaust regulations have been further strengthened. In addition, in addition to efforts starting from fuels such as bioethanol or biodiesel fuel, further weight reduction or the installation of exhaust gas recirculation (EGR (Exhaust Gas Recirculation)), DPF (Diesel Particulate Filter, diesel parti...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23G1/32C21D9/46C22C38/00C22C38/26C22C38/54C23G1/08
CPCC21D9/46C21D6/002C21D2211/005C22C38/00C22C38/001C22C38/002C22C38/004C22C38/005C22C38/008C22C38/02C22C38/04C22C38/06C22C38/20C22C38/22C22C38/24C22C38/26C22C38/28C22C38/30C22C38/32C22C38/42C22C38/44C22C38/48C22C38/60C23G1/086F02M2200/05F02M2200/9053F28D21/0003F28F21/083F28F2275/04B23K1/00C21D6/004C21D6/008C25F1/06C23G1/00C23G1/19C23G1/28B23K1/0012B23K1/19
Inventor 平出信彦松桥透森弘纪世小野直人
Owner NIPPON STEEL STAINLESS STEEL CORP
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