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Ferritic stainless steel with excellent corrosion resistance at welds

A stainless steel and system technology, applied in the furnace type, furnace, heat treatment furnace, etc., can solve problems such as welding cracks, and achieve the effect of excellent corrosion resistance

Active Publication Date: 2018-09-07
JFE STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, when welding steel containing a large amount of Nb, solid solution Nb is formed in the form of coarse Nb precipitates in the welded part, which may cause problems such as welding cracks
In consideration of manufacturability and practicality, it cannot be said that it is not the best measure to obtain corrosion resistance of welded parts by adding only carbonitride-forming elements such as Nb and Ti.

Method used

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  • Ferritic stainless steel with excellent corrosion resistance at welds
  • Ferritic stainless steel with excellent corrosion resistance at welds
  • Ferritic stainless steel with excellent corrosion resistance at welds

Examples

Experimental program
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Effect test

Embodiment 1

[0078] Hereinafter, the present invention will be described in more detail based on examples.

[0079]Stainless steel having the chemical composition shown in Table 1 was melted in a 50 kg small vacuum melting furnace. These ingots were heated at 1150° C. for 1 hour, and then hot-rolled to obtain 3.5 mm-thick hot-rolled sheets. Next, after annealing these hot-rolled sheets at 950°C for 1 minute, the surface was subjected to shot blasting, and then immersed in a 20% by mass sulfuric acid solution at a temperature of 80°C for 120 seconds. % nitric acid and 3 mass % hydrofluoric acid by immersing in a mixed acid at a temperature of 55° C. for 60 seconds to carry out pickling and descaling.

[0080] Furthermore, it was cold-rolled to a plate thickness of 0.8mm, and recrystallization annealed at 900°C for 1 minute in a weakly reducing atmosphere (hydrogen: 5% by volume, nitrogen: 95% by volume, dew point: -40°C) to obtain a cold-rolled annealed plate. The cold-rolled annealed sh...

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PUM

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Abstract

The present invention provides ferritic stainless steel excellent in corrosion resistance of welded parts. A ferritic stainless steel characterized by containing, in mass %, C: 0.001 to 0.025%, Si: 0.05 to 0.30%, Mn: 0.35 to 2.0%, P: 0.05% or less, S: 0.01% or less, Al: 0.05 to 0.80%, N: 0.001 to 0.025%, Cr: 16.0 to 20.0%, Ti: 0.12 to 0.50%, Nb: 0.002 to 0.050%, Cu: 0.30 to 0.80%, Ni: 0.05% to less than 0.50% %, V: 0.01 to 0.50%, and satisfy the following formula (1), and the balance is composed of Fe and unavoidable impurities. 0.50<25×C+18×N+Ni+0.11×Mn+0.46×Cu(1). In addition, the symbol of the element in a formula means content (mass %) of each element.

Description

technical field [0001] The present invention relates to a ferritic stainless steel whose corrosion resistance is less prone to decrease due to carbon and nitrogen intruded from a material to be welded into a weld seam or nitrogen intruded from the atmosphere during welding. Background technique [0002] Ferritic stainless steel can secure corrosion resistance with a smaller amount of Ni than austenitic stainless steel. Since Ni is an expensive element, ferritic stainless steel can be produced at a lower cost than austenitic stainless steel. In addition, compared with austenitic stainless steel, ferritic stainless steel has excellent characteristics such as high thermal conductivity, small thermal expansion coefficient, and less occurrence of stress corrosion cracking. Therefore, ferritic stainless steel is used in a wide range of applications such as automotive exhaust system components, building materials such as roofs, doors and windows, kitchen equipment, water storage t...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/00C22C38/58C22C38/60C21D9/46
CPCC21D6/002C21D9/46C22C38/002C22C38/004C22C38/005C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50C22C38/52C22C38/54C22C38/58C22C38/60
Inventor 吉野正崇太田裕树
Owner JFE STEEL CORP