Effect of GMAW Heat Input on the Microstructure and Mechanical and Fatigue Behavior of Dissimilar Welds of Ultrahigh Strength Steel and Duplex Stainless Steel

2017 ◽  
Author(s):  
Hamed Tasalloti Kashani ◽  
Mohammad Dabiri ◽  
Paul Kah ◽  
Jukka Martikainen
Keyword(s):  
Stainless Steel ◽  
Duplex Stainless Steel ◽  
Heat Input ◽  
Fatigue Behavior ◽  
Hardness Profile ◽  
Ultrahigh Strength ◽  
Ultrahigh Strength Steel ◽  
Dissimilar Welds ◽  
Lower Heat ◽  
Geometrical Effects

The effect of heat input on the microstructure and mechanical properties of dissimilar welds of direct-quenched ultrahigh strength steel (Optim 960 QC) and duplex stainless steel (UNS S32205) was studied. The effect of heat input on grain coarsening and the proportion of bainite-martensite on the ferritic side and ferrite-austenite on the duplex side was clearly evident. The hardness profile showed a trend of increasing hardness with lower heat input. Enhancement in tensile strength corresponded to lower heat input and increase in hardness. The elongation values and bend behavior were roughly the same for all the specimens; there was no clear link to the heat input. Moderate heat input gave optimum impact toughness in the weld and the ferritic HAZ. The fatigue performance of the specimens demonstrated the profound influence of geometrical effects. However, the effect of microstructural characteristics on fracture location was also observed.

Corrosion Resistance of Dissimilar GTA Welds of Pipeline Steel and Super Duplex Stainless Steels in Synthetic Brine

CORROSION ◽  
10.5006/3746 ◽  
2021 ◽  
Author(s):  
Víctor Vargas ◽  
Apolinar Albiter-Hernandez ◽  
Marco Dominguez Aguilar ◽  
Gerardo Altamirano-Guerrero ◽  
Cuahtemoc Maldonado
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Duplex Stainless Steel ◽  
Pipeline Steel ◽  
Localized Corrosion ◽  
Nickel Wire ◽  
Super Duplex Stainless Steel ◽  
Gas Tungsten Arc ◽  
Dissimilar Welds ◽  
Super Duplex Stainless Steels

The effect of weld passes and single V grove designs, on the corrosion resistance of dissimilar welds of a low alloy steel and a super-duplex stainless steel, was studied in synthetic brine. Welds were manufactured in argon by gas tungsten arc (GTA) technique and joined by a high nickel wire of super-duplex stainless steel. Samples of weld regions were characterized by composition scans, electrochemical measurements, micro-hardness and scanning electron microscopy. In X52/ER2594, a transition region (TR) of grain boundaries type II and a band of martensite were formed. The base metal of X52 underwent the highest corrosion rate and localized corrosion occurred in the heat affected zone. Interface ER2594/25Cr7Ni and 25Cr7Ni showed the presence of pitting near intermetallics.

Influence of Argon-Nitrogen Gas to Balance the Microstructure in the Welding of Super Duplex Stainless Steel

2016 ◽  
Vol 836 ◽  
pp. 165-172
Author(s):  
Suheni
Keyword(s):  
Stainless Steel ◽  
Weld Metal ◽  
Duplex Stainless Steel ◽  
Heat Input ◽  
Oil And Gas ◽  
Austenite Phase ◽  
Super Duplex Stainless Steel ◽  
Shielding Gas ◽  
Input Variables ◽  
Protective Gas

Super duplex stainless steel is steel that has a corrosion resistance and good mechanical strength so that used in industry especially in oil and gas and petrochemical industry. In use in the field is often used for the connection process by welding methods. To produce good welds, it should be noted that the welding procedures and parameters used , especially the heat input. In this study is used the heat input variables shielding gas composition to determine how much influence on the balance of ferrite - austenite phase structure in the weld stainless steels SAF 2507 super duplex with tungsten inert gas welding method (TIG). Heat input varied by applying different welding speed 1,3,4 and 5 mm /sec while the shielding gas is used 100 % argon, 98 % argon + 2 % nitrogen and 95 % argon + 5 % nitrogen. The result showed that at different welding speeds generated depth and width of the weld metal which is different. Likewise the use of protective gas will produce a different ratio wide and deep of weld metal which is different. By using protective gas 95 % argon + 5 % nitrogen squeak - ausenit phase, resulting in weld metal that is relatively balanced than others. On a slow welding in addition to produce a large heat input also produces weld metal hardness at high and affect the growth of the austenite phase. The higher the heat input ( 2,280 kJ / mm ) , the lower the austenite phase in the weld metal.

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