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Lean duplex stainless steel and method of manufacturing the same

a duplex stainless steel and duplex technology, applied in the field of lean duplex stainless steel, can solve the problems of increasing manufacturing costs, many limitations of 400 series stainless steel in its use as a thick plate, and its formability does not reach the level of 300 series stainless, so as to minimize or exclude the alloying elements, reduce the manufacturing cost of duplex stainless steel, and save resources

Inactive Publication Date: 2018-12-20
POHANG IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention aims to minimize or eliminate the use of certain alloying elements in duplex stainless steel to save resources and reduce manufacturing costs. Additionally, by controlling the components of silicon and nitrogen, the stability of the austenite phase at room temperature is increased, resulting in an elongation of at least 30% and a corrosion resistance level of 400 series general steel.

Problems solved by technology

300 series stainless steel which is excellent in corrosion resistance and workability contains expensive raw materials such as Ni and Mo, and thus, 400 series stainless steel has been discussed as an alternative to this, but there is a problem in that its formability does not reach to the level of 300 series stainless steel.
A thick plate which is relatively less formed than a hot / cold rolled sheet is applicable to the corrosion resistance of 400 series depending on the usage environment, but 400 series stainless steel has many limitations in its use as a thick plate due to inferior impact characteristics and deterioration of welded parts.
However, since these duplex stainless steels contain high-priced elements such as Ni and Mo, there is a disadvantage in that not only the manufacturing cost is increased but also the price competitiveness with other steel types is inferior as Ni and Mo are consumed.
A steel grade corresponding to this demand is not currently developed, and the 400 series stainless steel has low DBTT characteristics due to a structural factor, thus the impact characteristics are very weak, and there is a problem in that it is difficult to use as a thick plate due to the coarsening of the weld HAZ structure.
That is, it is difficult to realize a duplex steel structure having the ferrite phase and the austenite phase at 20%Cr or less, and the martensite phase formed during the cooling process lowers the elongation of the material and causes a problem that makes processing impossible such as a tube making process.

Method used

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  • Lean duplex stainless steel and method of manufacturing the same
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Embodiment Construction

[0033]A lean duplex stainless steel according to an embodiment of the present invention comprises, by weight percent, 0.05 to 0.1% of carbon (C), 2.0 to 4.0% of silicon (Si), 4.0 to 8.0% of manganese (Mn), 13.0 to 15.0% of chromium (Cr), 0.05 to 0.15% of nitrogen (N), with the remainder being iron (Fe) and other unavoidable impurities.

MODE FOR INVENTION

[0034]Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0035]The following embodiment is presented to fully convey the idea of the present invention to those skilled in the art to which the present invention belongs. The present invention is not limited to the embodiments shown herein but may be embodied in other forms. In order to clarify the present invention, the drawings may omit the showing of parts not related to the description, and the size of the components may be slightly expressed in a somewhat exaggerated manner to facilitate understanding.

[0036]A lea...

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Abstract

A lean duplex stainless steel and a method of manufacturing the same are disclosed. A lean duplex stainless steel according to an embodiment of the present invention comprises, by weight percent, 0.05 to 0.1% of carbon (C), 2.0 to 4.0% of silicon (Si), 4.0 to 8.0% of manganese (Mn), 13.0 to 15.0% of chromium (Cr), 0.05 to 0.15% of nitrogen (N), with the remainder being iron (Fe) and other unavoidable impurities. Therefore, it is possible to minimize the manufacturing costs by minimizing or excluding the alloy components of Cr, Ni, Mo, and the like. in the component system of the duplex stainless steel, to secure an elongation of 30% or more and to secure a corrosion resistance level of 400 series general steel.

Description

TECHNICAL FIELD[0001]The present invention relates to a lean duplex stainless steel and a method of manufacturing the same having an austenite-ferrite dual phase structure minimizing the content of high-priced alloy elements such as Ni and Mo in the component system and controlling the phenomena of thermal martensitic transformation and plasticity-induced martensitic transformation.BACKGROUND ART[0002]In general, austenitic stainless steel with good workability and corrosion resistance contains iron (Fe) as a base metal and chromium (Cr) and nickel (Ni) as main raw materials, and has been developed as a variety of steel types to meet various applications by adding other elements such as molybdenum (Mo) and copper (Cu).[0003]300 series stainless steel which is excellent in corrosion resistance and workability contains expensive raw materials such as Ni and Mo, and thus, 400 series stainless steel has been discussed as an alternative to this, but there is a problem in that its formabi...

Claims

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Application Information

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IPC IPC(8): C22C38/58C22C38/34C22C38/00C21D8/02
CPCC22C38/58C22C38/34C21D2211/005C21D8/0263C22C38/001C22C38/00C22C38/38C21D6/002C21D6/005C21D6/008C21D2201/02C21D2211/001C21D8/02
Inventor JEON, JONG JINKIM, BONG WN
Owner POHANG IRON & STEEL CO LTD
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