scholarly journals TOPSIS – Taguchi Analysis of Notch Parameters on the Fatigue Life of Super Duplex Stainless Steel

2019 ◽  
Vol 9 (2) ◽  
pp. 3649-3654
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Duplex Stainless Steel ◽  
Super Duplex Stainless Steel ◽  
Central Angle ◽  
Element Analysis ◽  
Notch Width ◽  
Topsis Approach ◽  
The Impact ◽  
Steel Design

Purpose: The purpose of the current research is to quantify the impact of notch parameters viz. width, depth and central angle (perimeter length) on the fatigue life of UNS S32760 grade of super duplex stainless steel. Design/ Methodology/ Approach: Finite element analysis approach is implemented by using the popular software package ANSYS 18.1 and the experimental runs are selected as per the requirements of Taguchi L9 orthogonal array. TOPSIS approach is used along with Taguchi method to know about the impact of notch parameters and arrive at the optimal condition. Findings: It is quantitatively established that notch depth is the most critical parameter and it affects the fatigue life to a greater extent (63.4%) when compared to other factors viz. notch width (10.6%) and central angle (7.31%).

Enhancing fatigue resistance of activated tungsten inert gas welded UNS S32750 super duplex stainless steel by optimizing its technological properties

2020 ◽  
pp. 1-11
Author(s):  
A. Arunmani ◽  
T. Senthilkumar
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Duplex Stainless Steel ◽  
Fatigue Resistance ◽  
Process Parameters ◽  
Gas Flow ◽  
Welding Process ◽  
Travel Speed ◽  
Inert Gas ◽  
Super Duplex Stainless Steel

In engineering industries and heavy manufacturing plants, fatigue life of joints plays a pivotal role in determining the overall life span of the welded joint. In this paper, an advanced fusion joining technique, namely activated tungsten inert gas welding, was used for joining UNS S32750 super duplex stainless steel, with ZnO as activation flux. For the enhancement of fatigue resistance of joints, important welding process parameters were fluctuated according to a developed central composite design model. Empirical relationships were developed between the process parameters and the fatigue strength of the joints, which was correlated with the number of cycles to failure (NCF). Using analysis of variance, the significance of the developed fatigue model was ascertained. Using response surface methodology, optimization of process parameters for enhancement of fatigue resistance was done. It was observed that at the optimized activated tungsten inert gas weld process parameters of travel speed of welding torch at 69.85 mm/min, weld current at 125.20 A, and shielding gas flow rate at 14.77 L/min, a high fatigue life of 7.66396 × 108 NCF was obtained and the model was validated to very high predictability. Microstructural variations in the fatigue-tested specimens were evaluated for identifying the grain modifications.

scholarly journals Effect of Embrittlement on the Microstructure, Mechanical and Wear Properties of Aged Super Duplex Stainless Steel

2020 ◽  
Vol 7 ◽  
Author(s):  
Mahesh Davanageri ◽  
D. Disha ◽  
K. Raju
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Dry Sliding Wear ◽  
Super Duplex Stainless Steel ◽  
Wear Properties ◽  
Solution Treated ◽  
Α Phase ◽  
Two Phases ◽  
The Impact

In the present study, the effect of embrittlement on the microstructural features, mechanical and dry sliding wear properties of AISI 2507 super duplex stainless steel (SDSS) has been discussed. Prior to heat treatment the SDSS has been solution treated. Further, SDSS has been heat treated at 475°C for 60 min and then quenched in water and oil at room temperature. The heat treatment has led to the embrittlement in SDSS owing to the decomposition of ferrite phase by spinodal decomposition into two phases, Cr-rich (α΄) phase and Fe-rich (α) phase. Embrittlement of super duplex stainless steel resulted in significant improvement in ultimate tensile strength and hardness. However, a decrease in the impact energy has been observed. Oil quenched super duplex steel has better wear resistance compared to water quenched and solution treated steels.

Effect of Cooling Time on Microstructure and Properties of 2507 Super Duplex Stainless Steel Welding Heat-Affect Zone

2018 ◽  
Vol 940 ◽  
pp. 53-58
Author(s):  
Yu Qing Zhou ◽  
De Ning Zou ◽  
Ke Xin Li ◽  
Wei Zhang ◽  
Rong Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Intermediate Phase ◽  
Heat Affect Zone ◽  
Morphology Evolution ◽  
Super Duplex Stainless Steel ◽  
Corrosion Tests ◽  
Σ Phase ◽  
Austenite Content ◽  
The Impact

The welding thermal simulation of 2507 Super Duplex Stainless Steel (SDSS) was investigated using Gleeble-3800 thermo-mechanical simulator. The morphology evolution of austenite and ferrite under different t8/5 and t12/8 were observed and compared. The impact tests and pitting corrosion tests under different t8/5 and t12/8 were conducted. The results showed that the austenite content increased and the austenitic morphology changed from allotriomorphic structure to strip or coarse-blocky structures with the increase of t8/5 and t12/8. The effect of t12/8 on the microstructure of welding Heat Affect Zone (HAZ) was more distinct than that of t8/5. The impact toughness of HAZ with the increase of t12/8 was improved due to higher austenite content, while that with the increase of t8/5 was slightly decreased due to the formation of intermediate phase, such as σ phase. The corrosion tests showed that the pitting resistance of HAZ was improved with the increase of t8/5 and t12/8, while the effect of t12/8 was especially evident.

Effect of Aging on the Microstructure and the Intergranular Corrosion Resistance of X2CrNiMoN25-7-4 Duplex Stainless Steel

2013 ◽  
Vol 203-204 ◽  
pp. 59-62 ◽  
Author(s):  
Pawel Szabracki ◽  
Tomasz Lipiński
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Duplex Stainless Steel ◽  
Stainless Steels ◽  
Intergranular Corrosion ◽  
Hot Cracking ◽  
Super Duplex Stainless Steel ◽  
Duplex Microstructure ◽  
The Impact

Stainless steels are used widely in many industries. A duplex microstructure offers a combination of advantages, including resistance to crevice and stress corrosion, reduced susceptibility to hot cracking in comparison with fully austenitic structures and excellent tensile strength. The paper discusses the effect of aging on the microstructure and corrosion resistance of X2CrNiMoN25-7-4 super duplex stainless steel. Low and predictable corrosion rate is an important parameter for steels operating in aggressive environments. Resistance to intergranular corrosion expressed by corrosion rate (mm/year) was determined in accordance with standard PN-EN ISO 3651-1. Metallographic studies were carried out to evaluate surface degradation and intergranular corrosion. The results support an evaluation of the impact that phase fraction changes caused by aging have on resistance to intergranular corrosion. The results of the corrosion analysis were used to develop mathematical models describing changes in corrosion rate over time for different phase fractions.

Effect of Weld Porosity on Super Duplex Stainless Steel Umbilical Tubes Under Hydrogen Induced Stress Cracking Exposure Condition

2019 ◽  
Author(s):  
M. Socariceanu ◽  
X. An
Keyword(s):  
Stainless Steel ◽  
Strain Rate ◽  
Duplex Stainless Steel ◽  
Slow Strain Rate ◽  
Exposure Condition ◽  
Super Duplex Stainless Steel ◽  
Stress Cracking ◽  
Induced Stress ◽  
Weld Porosity ◽  
The Impact

Abstract Super Duplex Stainless Steel (SDSS) is the preferred material utilized in steel tube umbilicals, due to its excellent corrosion resistance and high mechanical strength. SDSS is susceptible to Hydrogen Induced Stress Cracking (HISC) under the influence of a Cathodic Protection (CP) system, especially the welded zone. Porosity (relevant rounded indication) is one of the most common weld flaws that impacts the SDSS weld reject rate based on historical acceptance criteria. A study has been carried out investigating the influence of weld porosity on 25% Cr (SDSS) butt welded tube, under the effect of CP potential by using a Slow Strain Rate Testing (SSRT) technique. The study focused on the correlation between the level of porosity and the material mechanical performance when exposed to a simulated CP system in seawater at an elevated temperature. The impact of HISC was evaluated through an assessment of various tube welds including welds with different levels of porosity quantified by number, size and location of pores, when exposed directly to natural CP system in seawater for 4 and 8 weeks. Post hydrogen pre-charging, the samples were subjected immediately to a modified Slow Strain Rate Test (SSRT). After hydrogen charging and SSRT the resulting fracture morphology was examined using a scanning electron microscope (SEM), and the failure mode was assessed in relation to porosity locations. Experimental results indicate that all hydrogen pre-charged samples with or without pores decrease in ductility after exposure to the CP system which was further confirmed by the fractography analysis. It was observed that susceptibility of SDSS to HISC is broadly similar for welds with porosity or without porosity and brittle phenomena is more pronounced at the exposed surfaces of the samples. The study has demonstrated that the butt weld of SDSS umbilical tube with a controlled porosity level in line with ASME design codes does not show an increased susceptibility to HISC under CP system when compared to welds with no porosity.

ZERON 100

Alloy Digest ◽  
1993 ◽  
Vol 42 (11) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Duplex Stainless Steel ◽  
Heat Treating ◽  
Super Duplex Stainless Steel ◽  
Corrosion Performance ◽  
Temperature Performance ◽  
Offshore Oil

Abstract ZERON 100 is a super duplex stainless steel which is manufactured to give a guaranteed corrosion performance by using an equation to control the chemistry in those elements which will determine the corrosion resistance of the material. Major usages in seawater applications, particularly offshore oil gathering systems. This datasheet provides information on composition, hardness, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance as well as heat treating, machining, and joining. Filing Code: SS-555. Producer or source: Weir Material Services Ltd.

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