The effect of copper on secondary phase precipitation in duplex stainless steel – a thermodynamic calculations approach

2005 ◽  
Vol 96 (8) ◽  
pp. 918-923 ◽  
Author(s):  
Olena Smuk ◽  
Malin Selleby ◽  
Bill Bergman
2017 ◽  
Vol 889 ◽  
pp. 138-142 ◽  
Author(s):  
Amit Powar ◽  
Amol Gujar ◽  
Niketan Manthani ◽  
Vinayak Pawar ◽  
Rajkumar Singh

Duplex Stainless Steel (DSS) combines good mechanical strength and ductility with moderate to good corrosion resistance in a variety of environments. DSS are prone to the formation of various intermetallic phases (σ, χ, π, R), carbides (M23C6) and nitrides (Cr2N), when it exposed to temperatures lower than 1000°C. This study focuses on effect of secondary phase precipitation on impact toughness of ASTM A182 DSS. Cylindrical bar of DSS was open die forged in the temperature range of 1200-1050°C. After the forging, the bar was slow cooled by covering it with ceramic wool. This leads to the formation of σ phase at the ferrite/austenite interfaces and significantly reduced the impact toughness of the material. Solution treatment was done at different temperature and effect on toughness studied. The microstructural changes produced as consequences of the distinct test condition have been analyzed by means of optical and electron microscopy, X-ray diffraction.


Author(s):  
Irene Calliari ◽  
Marco Breda ◽  
Claudio Gennari ◽  
Luca Pezzato ◽  
Massimo Pellizzari ◽  
...  

Duplex and Super Duplex Stainless Steels are very prone to secondary phases formation related to ferrite decomposition at high temperatures. In the present paper the results on secondary phase precipitation in a 2510 Duplex Stainless Steel, heat treated in the temperature range 850-1050 °C for 3-30 minutes are presented. The precipitation starts at grain boundaries with a consistent ferrite transformation for very short times. The noses of the TTP curves are at 1000 °C for σ-phase and at 900 °C for χ-phase, respectively. The precipitation sequence involves a partial transformation of χ into σ, as previously evidenced in 2205 and 2507 grades. Furthermore, the experimental data were compared to the results of Thermo-Calc calculations.


Metals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 967
Author(s):  
Irene Calliari ◽  
Marco Breda ◽  
Claudio Gennari ◽  
Luca Pezzato ◽  
Massimo Pellizzari ◽  
...  

Duplex and Super Duplex Stainless Steels are very prone to secondary phases formation related to ferrite decomposition at high temperatures. In the present paper the results on secondary phase precipitation in a 2510 Duplex Stainless Steel, heat-treated in the temperature range 850–1050 °C for 3–30 min are presented. The precipitation starts at grain boundaries with a consistent ferrite transformation for very short times. The noses of the Time–Temperature–Precipitation (TTP) curves are at 1000 °C for σ-phase and at 900 °C for χ-phase, respectively. The precipitation sequence involves a partial transformation of χ into σ, as previously evidenced in 2205 and 2507 grades. Furthermore, the experimental data were compared to the results of Thermo-Calc calculations. Understanding and ability to predict phase stability in 2510 duplex stainless steel is a key factor to design optimal welding processes that avoid any secondary phase precipitation in the weld bead as well as in the heat-affected zone.


2015 ◽  
Vol 30 (3) ◽  
pp. 591-595 ◽  
Author(s):  
Heping Liu ◽  
Hu’er Sun ◽  
Bin Liu ◽  
Dazhao Li ◽  
Fenger Sun ◽  
...  

2010 ◽  
Vol 658 ◽  
pp. 380-383 ◽  
Author(s):  
Ying Han ◽  
De Ning Zou ◽  
Wei Zhang ◽  
Jun Hui Yu ◽  
Yuan Yuan Qiao

Specimens of 2507 super-duplex stainless steel aging at 850°C for 5 min, 15 min and 60 min were investigated to evaluate the pitting corrosion resistance in 3.5% NaCl solution at 30°C and 50°C. The results are correlated with the microstructures obtained with different aging time. The precipitation of σ phase remarkably decreases the pitting corrosion resistance of the steel and the specimen aged for 60 min presents the lowest pitting potential at both 30°C and 50°C. With increasing the ambient temperature from 30°C to 50°C, the pitting potential exhibits a reduction tendency, while this tendency is less obviously in enhancing the ambient temperature than in extending the isothermal aging duration from 5 to 60 min. SEM analysis shows that the surrounding regions of σ phase are the preferable sites for the formation of corrosion pits which grew up subsequently. This may be attributed to the lower content of corrosion resistance elements in these regions formatted with σ phase precipitation.


Sign in / Sign up

Export Citation Format

Share Document