Papers by Keyword: Duplex Stainless Steel

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Authors: Lei Chen, Xiao Cong Ma, Ming Jia Wang, Hua Gui Huang
Abstract: The flow behavior and microstructural evolution of an as-wrought duplex stainless steel has been investigated by Gleeble-3500 thermal-mechanical simulator within the temperature range of 950-1200°C and the strain rate range of 0.1-10s-1. The flow curves exhibited a peak stress characteristic followed by dynamic softening and the strain for appearance of steady stress is bigger at higher strain rate than at lower strain rate. The apparent activation energy (Q) and the apparent stress exponent (n) of the test steel are obtained to be about 462 kj/mol and 3.95, respectively. The relationship between peak stress (σp) and Zener-Holomon parameter (Z) is obtained, whereby the σp can be predicted at differern hot working conditons. The results of microstructural observation show that the austenite softens by the dynamic recrystallization (DRX) which can be dominantly responsib le for dynamic softening, while the ferrite phase mainly continues to exhibit dynamic recovery (DRV).
Authors: Yuan Yuan Cui, Yun Fei Jia, Fu Zhen Xuan
Abstract: The cyclic deformation behavior of the austenite and ferrite phase in an austenite-ferrite duplex stainless steel was studied by using the load-controlled cyclic nanoindentation approach. The results showed that the maximum penetration depth onto both austenite and ferrite phases increased continuously while the rate decreased gradually and finally reached to a constant during the repeated indentation. Both transient state and quasi-steady state were observed for the penetration depth per cycle on both of the austenite and ferrite phases with the increased cycles. By contrast, both the penetration depth and rate per cycle into the austenite phase were larger than those into the ferrite phase. This was ascribed to the stress-induced densification in the austenite and ferrite phases and strain-induced transformed martensite in the austenite phase.
Authors: Rafidah Hasan, Iswadi Jauhari, S.M. Yunus, Raden Dadan Ramdan, Nik Rozlin Nik Masdek
Abstract: Boronizing is a method to increase the surface hardness of engineering components [1]. This is beneficial especially when the components are always in surface contact with other materials. In this study, boronizing treatment was successfully done on duplex stainless steel (DSS). Two types of DSS with different microstructure were boronized – the as-received DSS and the fine grain DSS. The morphology of boride layer formed on boronized DSS is compact and smooth. The boride layer thickness for both DSS ranged from 9 to 32 +m. Depending on boronizing time and temperature, the hardness of boronized fine grain DSS is between 1014 HV to 2601 HV. The values are higher than that of the as-received DSS which is between 797 HV to 2311 HV. The result shows that there is a different in hardness of boride layer for two different grain sizes of DSS although the layer thickness formed is about the same in depth.
Authors: Prachya Peasura, Narasak Duangsrikaew, Santirat Nansaarng
Abstract: In this research, the post weld heat treatment (PWHT) of duplex stainless steel (DSS) was study. The PWHT process can be affected by differing parameters. The specimen was duplex stainless steel UNS31803 grade sheet of 10 mm thickness. The PWHT parameters were analyzed by application of full factorial design. The factors used in this study were PWHT temperature of 650, 750, and 850 C with PWA time of 1, 2, 4 and 8 hours. The welded specimens were tested with micro vickers hardness and ferrite content testing according to ASTM E3-11 code. The result showed that both of PWHT temperature and PWHT time interaction on hardness and ferrite content for 95% confidential (P value < 0.05). The factor in most effect of hardness was the PWHT temperature of 850C and PWHT time for 4 hour at the hardness of 277.73 HV. The ferrite was the most ferrite content for 77.39% resulted in corrosion resistance due to suitable of PWHT temperature 750 C and PWHT time for 8 hour. Finally, form PWHT process with the information was used choosing the appropriate for PWHT parameters to duplex stainless steel welds.
Authors: A.F. Armas, Suzanne Degallaix, Gérard Degallaix, S. Hereñú, C. Marinelli, I. Alvarez-Armas
Abstract: The cyclic behavior of type DIN 1.4460 duplex stainless steels in as-received and aged conditions was investigated at room temperature and at 500°C. At room temperature, the aged samples showed embrittlement effects such as loss of toughness and reduction of fatigue life. At 500°C, beneficial effects of the synergy between temperature and strain cycling were observed. It is proposed that at high temperature in the ferrite the strain cycling can decompose the chemical composition fluctuations, promoting a demodulation of the spinodal decomposition formed by aging.
Authors: Hui Zhang, Yong Jun Zhang, Jing Tao Han, Yuan Dong, Jie Ren Hu
Abstract: In hot rolling process of 2205 duplex stainless steel, it was found that bright line defects are mainly located at where is about distance of 200 mm from two sides of hot rolled plate. The forming reason of bright line defects is studied by means of metallographic microscope, scanning electron microscope (SEM) combined with energy dispersive spectrometer (EDS). It is concluded that the formation of bright line defects has associated with sticking and that the temperature reduction on the edge of hot rolling plate causes a high percentage of austenite phase which is network structure. In order to prevent or avoid the happening of the sticking phenomenon, it is necessary to uniformly distribute the oxide on the strip surface by controlled rolling process.
Authors: José A. Jiménez, Manuel Carsí, Georg Frommeyer, Oscar A. Ruano
Authors: D. Devakumar, D.B. Jabaraj, V.K. Bupesh Raja, P. Periyasamy
Abstract: The purpose of this study is to evaluate the mechanical and metallurgical properties of dissimilar metal weld joints between duplex stainless steel/Cold Reduced low carbon Steel (CRS) by Gas Tungsten Arc Welding (GTAW) process. The dissimilar 2 mm thickness plates of duplex stainless steel and cold reduced low carbon steel, conforming to AISI 2205 and IS 513_2008 CR2_D were butt welded by means of gas tungsten arc welding using argon as shielding gas. The butt welding joint arrangement was used for this experiment using E 309L electrode as filler metal. The joints were investigated for mechanical properties and microstructure. Tensile, Hardness and bend tests were carried out to evaluate the mechanical properties. Optical microscopy was used to explore the microstructure. The micro structural examination of the weld region revealed dendritic delta ferrite. Micro examination of DSS base metal revealed elongated grains of austenite (white) with ferrite (Brown). Micro examination of CRS base metal discloses deformed grains of ferrite present in the matrix. Fracture analysis was conducted for the failure part with Scanning Electron Microscope (SEM) and found ductile fracture occurred at CR steel side.
Authors: Rafidah Hasan, Iswadi Jauhari, Hiroyuki Ogiyama, Raden Dadan Ramdan
Abstract: Superplastic boronizing (SPB) is a new surface hardening technique utilizing the ultra high plasticity phenomenon in metals in carrying out boronizing process. In boronizing, boron atoms are diffused into the metal substrate to form a hard boride layer. In this research, a new compression method for the SPB process was introduced. A clamp with an initial compressive load of about 1960 N was used. Thermo-mechanical treated duplex stainless steel (DSS) with fine grain microstructure which can show superplastic behavior at high temperatures was used as the superplastic material. SPB experiments were conducted at temperatures between 1123 and 1223 K for durations of 1 - 6 hours. The boronized specimens demonstrated thin, smooth and compact morphology of boride layer. The boride layer thickness was within ±10 0m - ±46.2 0m. On the boride layer, only the favorable single phase of Fe2B was detected. High value of surface hardness was observed in the range of ±847 HV - ±2914 HV. The overall results from the study show that the SPB process can significantly improve the surface properties of DSS.
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