Examination of the Orientation Relationships between the Main Phases of Duplex Stainless Steel by EBSD

2007 ◽  
Vol 537-538 ◽  
pp. 297-302
Author(s):  
Tibor Berecz ◽  
Péter János Szabó
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Electron Backscatter Diffraction ◽  
Duplex Stainless Steels ◽  
Alloying Elements ◽  
Orientation Relationships ◽  
Σ Phase ◽  
Electron Backscatter ◽  
Backscatter Diffraction

Duplex stainless steels are a famous group of the stainless steels. Duplex stainless steels consist of mainly austenitic and ferritic phases, which is resulted by high content of different alloying elements and low content of carbon. These alloying elements can effect a number of precipitations at high temperatures. The most important phase of these precipitation is the σ-phase, what cause rigidity and reduced resistance aganist the corrosion. Several orientation relationships have been determined between the austenitic, ferritic and σ-phase in duplex stainless steels. In this paper we tried to verify them by EBSD (electron backscatter diffraction).

Crystallographic relations during decomposition of the ferritic phase by isothermal ageing of duplex stainless steel

2012 ◽  
Vol 46 (1) ◽  
pp. 135-141 ◽  
Author(s):  
Tibor Berecz ◽  
Peter J. Szabo
Keyword(s):  
Stainless Steels ◽  
Electron Backscatter Diffraction ◽  
Parent Phase ◽  
Duplex Stainless Steels ◽  
Σ Phase ◽  
Orientation Relations ◽  
Mathematical Expressions ◽  
Duplex Steel ◽  
Isothermal Ageing ◽  
Backscatter Diffraction

In highly alloyed and duplex stainless steels the range of alloying elements leads to many different phases precipitating at higher temperatures. Duplex stainless steels consist of almost equal ratios of austenite and ferrite, and between 923 and 1273 K the ferrite begins decomposing into secondary austenite (γ2) and the σ phase. Several orientation relations between the austenitic, ferritic and σ phases have been determined by other researchers. The calculation and testing of mathematical expressions for these orientations are important for a close understanding of changes in duplex steel hardness, ductility, and other qualitative measures imposed by annealing or heat ageing. The method described in this article also offers an approach for determining parent phase orientations from inherited orientations in other metallic microstructures. When the orientation relations of adjacent grains calculated from mathematical equations and those measured by electron backscatter diffraction were compared, naturally it was found that the average orientation differs less between grains that inherit matrix structure from common parents. However, it was also found that the degree of difference depended on the variants involved in the orientations. This phenomenon can be explained by features of the microstructure and decomposition of the ferritic phase: initially the microstructure contains only primary austenite (γ1) and ferrite, then after a while it contains [beside primary (γ1) austenite] increasing amounts of secondary (γ2) austenite and the σ phase, and decreasing amounts of ferrite. The presence of two variants of austenite makes it difficult to verify parent relations for secondary (γ2) austenites.

The Interface Character Distribution and Intergrannular Corrosion Resistance of Duplex Stainless Steel UNS S32304

2016 ◽  
Vol 879 ◽  
pp. 536-541
Author(s):  
Jian Sheng Zhang ◽  
Yan Li Zhu ◽  
Xiao Ying Fang ◽  
Wen Hong Yin ◽  
Cong Xiang Qin
Keyword(s):  
Solid Solution ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Stainless Steels ◽  
Electron Backscatter Diffraction ◽  
Solution Annealing ◽  
Phase Boundaries ◽  
Electron Backscatter ◽  
Character Distribution ◽  
Backscatter Diffraction

The duplex stainless steels (UNS S32304) after solid solution annealing at two different temperature (1323K and 1573K) were subjected to the same cold rolling with ε =3 and subsequent annealing for 230 min at 1323 K . The corresponding interface character distribution (ICD) were determined by electron backscatter diffraction (EBSD). The results show that a larger population of phase boundaries (PB) having K-S orientation relationship (OR) between the neighboring δ and γ grains was introduced and therefore higher intergrannular corrosion resistance (ICR) were resulted in the specimen initially solid-solution annealed at 1573K.

Effect of Different Cooling Rate on HAZ Microstructure of 2205 Duplex Stainless Steels

2009 ◽  
Author(s):  
Qingren Xiong ◽  
Yaorong Feng ◽  
Wenzhen Zhao ◽  
Chunyong Huo ◽  
Chuan Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Cooling Rate ◽  
Stainless Steels ◽  
Duplex Stainless Steels ◽  
Temperature Range ◽  
2205 Duplex Stainless Steel ◽  
Microstructure Transformation ◽  
Microstructure Morphology ◽  
Phase Proportion

The effects of cooling rate ω8/5 and ω12/8 on the simulated HAZ microstructure transformation in 2205 duplex stainless steel are studied in this paper. The results indicate that 1200°C ∼ 800°C is the temperature range in which the microstructure transits the most violently for 2205 steel, and is also the cooling interval, that affects the phase proportion and microstructure morphology the most distinctly. Accordingly, It is more efficient to use ω12/8 as the parameter to investigate the microstructure transformation of welding HAZ microstructure of this material. The cooling rate in this interval will affect the microstructure transformation of HAZ microstructure of 2205 steel remarkably.

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