Phase stability study on wrought duplex and super duplex stainless steels grade 4A, 5A and 6A at elevated temperatures and the effect on their mechanical properties

2019 ◽  
Author(s):  
K. Adhitya ◽  
K. Thillairajan ◽  
D. Ravi Shankar
Keyword(s):  
Mechanical Properties ◽  
Phase Stability ◽  
Stainless Steels ◽  
Elevated Temperatures ◽  
Stability Study ◽  
Duplex Stainless Steels ◽  
Super Duplex Stainless Steels

Effects of Heat Input Conditions on the Local Thermophysical Properties of Super Duplex Stainless Steels

2018 ◽  
Vol 930 ◽  
pp. 317-321
Author(s):  
José Adilson de Castro ◽  
Gláucio Soares da Fonseca ◽  
D.S.S. Almeida ◽  
L.C.R. Lopes ◽  
C.R. Xavier ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Mechanical Strength ◽  
Stainless Steels ◽  
Thermal History ◽  
Duplex Stainless Steels ◽  
Measured Temperature ◽  
Sem Images ◽  
Super Duplex Stainless Steels ◽  
Welding Procedure

The thermal properties of the super duplex stainless steels are strongly affected by the thermal history when welding procedure are applied leading to substantial changes on the mechanical properties of the welding region. The controlled dual phase microstructure (ferrite and austenite) guarantee excellent mechanical properties such as mechanical strength and corrosion resistance, in addition to small thermal expansion coefficient and high thermal conductivity. In this research a model able to predict the thermal history of the welding pieces coupled with local mechanical properties developed during welding procedure is developed. The model was verified by measured temperature profile and used to predict local properties such as grain size evolution, hardness and mechanical strength. An inverse method was implemented to obtain the parameters fitting for the grain growth evolution, hardness and yielding strength compatible with the final microstructure and grain size measured using SEM images and stereological techniques.

Hot Cracking Susceptibility in Duplex Stainless Steel Welds

2018 ◽  
Vol 941 ◽  
pp. 679-685
Author(s):  
Kazuyoshi Saida ◽  
Tomo Ogura
Keyword(s):  
Stainless Steels ◽  
Laser Beam Welding ◽  
Austenitic Stainless Steels ◽  
Hot Cracking ◽  
Duplex Stainless Steels ◽  
Solidification Cracking ◽  
Solidification Mode ◽  
Gas Tungsten Arc ◽  
Varestraint Test ◽  
Super Duplex Stainless Steels

The hot cracking (solidification cracking) susceptibility in the weld metals of duplex stainless steels were quantitatively evaluated by Transverse-Varestraint test with gas tungsten arc welding (GTAW) and laser beam welding (LBW). Three kinds of duplex stainless steels (lean, standard and super duplex stainless steels) were used for evaluation. The solidification brittle temperature ranges (BTR) of duplex stainless steels were 58K, 60K and 76K for standard, lean and super duplex stainless steels, respectively, and were comparable to those of austenitic stainless steels with FA solidification mode. The BTRs in LBW were 10-15K lower than those in GTAW for any steels. In order to clarify the governing factors of solidification cracking in duplex stainless steels, the solidification segregation behaviours of alloying and impurity elements were numerically analysed during GTAW and LBW. Although the harmful elements to solidification cracking such as P, S and C were segregated in the residual liquid phase in any joints, the solidification segregation of P, S and C in LBW was inhibited compared with GTAW due to the rapid cooling rate in LBW. It followed that the decreased solidification cracking susceptibility of duplex stainless steels in LBW would be mainly attributed to the suppression of solidification segregation of P, S and C.

Hardening of Aged Duplex Stainless Steels by Spinodal Decomposition

2004 ◽  
Vol 10 (3) ◽  
pp. 349-354 ◽  
Author(s):  
F. Danoix ◽  
P. Auger ◽  
D. Blavette
Keyword(s):  
Mechanical Properties ◽  
Impact Toughness ◽  
Spinodal Decomposition ◽  
Stainless Steels ◽  
Aging Process ◽  
Atom Probe ◽  
Duplex Stainless Steels ◽  
Detailed Knowledge ◽  
Iron Chromium

Mechanical properties, such as hardness and impact toughness, of ferrite-containing stainless steels are greatly affected by long-term aging at intermediate temperatures. It is known that the α-α′ spinodal decomposition occurring in the iron–chromium-based ferrite is responsible for this aging susceptibility. This decomposition can be characterized unambiguously by atom probe analysis, allowing comparison both with the existing theories of spinodal decomposition and the evolution of some mechanical properties. It is then possible to predict the evolution of hardness of industrial components during service, based on the detailed knowledge of the involved aging process.

Characterization of Dissimilar Welded Joints Between Austenitic and Duplex Stainless Steel Grades for Liquid Tank Applications

2018 ◽  
Author(s):  
G. Ubertalli ◽  
M. Ferraris ◽  
P. Matteis ◽  
D. Di Saverio
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Stainless Steels ◽  
Welded Joints ◽  
Industrial Applications ◽  
Duplex Stainless Steels ◽  
Steel Pipes ◽  
Steel Grades ◽  
Welding Processes

Lean duplex stainless steels have similar corrosion and better mechanical properties than the austenitic grades, which ensure their extensive spreading in industrial applications as a substitute of austenitic grades. In the construction of liquid tanks, however, it is often necessary to weld such steels with a range of fittings which are commonly fabricated with austenitic stainless steel grades. Therefore, this paper examines dissimilar welded joints between LDX 2101 (or X2CrMnNiN22-5-2) lean duplex stainless steels plates and austenitic stainless steel pipes, carried out by different arc welding processes. The investigation focuses on the correlation between the welding procedures and the microstructural and mechanical properties of the welded joints.

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