Mechanical Behavior of Overlap-Welded of Dissimilar Steels (Structural-Stainless) under Monotonic Load

2012 ◽  
Vol 557-559 ◽  
pp. 1268-1274 ◽  
Author(s):  
Andrés L. García Fuentes ◽  
Pierre Bazán ◽  
Leiry Centeno ◽  
Magaly Ramos ◽  
Alberto Velázquez Del Rosario

The research shows the characterization of mechanical properties in dissimilar steel welded unions: a structural steel ASTM A537 (I) overlap welded with an austenitic stainless steel ASTM A240 (304L) through semiautomatic electrical arc welding process protected by inert gas (GMAW); Argon is used as a protecting gas and austenitic stainless steel ASTM A240 (308L) as a supplier material. Samples were tested in not welded conditions so as to characterize the materials involved in the research, and they were also tested in welded conditions, not being submitted to pre and post welding Thermal Treatment (TT). Welded-based material samples were characterized through Optical Microscopy (OM) and Scanning Electron Microscopy (SEM), an inspection of Not Destructive Test (NDT) with penetrating liquids and ultrasound was also conducted. The following mechanical tests were completed, not only on the Base Metals (BM), on the Welding Join (WJ) as well: Vickers micro hardness profile, tension, and face bending test. Results showed a proper mechanical steel behavior, welded by GMAW procedure, under monotonic, in spite of the relatively high values of microhardness in the Heat Affected Zone (HAZ), specifically near the fusion line between weld and stainless steel.

Author(s):  
G.T. Gopalakrishna ◽  
B.S. Ajaykumar ◽  
K.R. Vishnu

Austenitic stainless steels are very important material and extensively used for various applications in fertilizer industry, petrochemical industry, nuclear industry and food industry. Austenitic stainless steel 316L alloyed with small percentage of nitrogen is called 316LN. 316LN is widely used only in nuclear applications and it is also called high temperature steels. This nitrogen alloyed steels 316LN will work at higher temperature environment along with radiation environment without losing its properties. The welding of this 316LN steel poses challenge due to problems like sensitization to inter granular corrosion, stress corrosion cracking and even hot cracking. Selecting the type of welding and filler material is more important for welding the 316LN austenitic stainless steel (SS). In this paper SS 316LN material is being welded with TIG and MIG welding. Three pairs of SS 316LN plates were used for experimental work. Filler electrode ER316L is used for TIG and MIG121 is used for MIG welding. After the welding process, hardness test, tensile test and bending test were performed to check the mechanical properties of the specimen. Microstructure of the specimen is observed at the weld region. The results show that the welded joint is stronger than the base material in TIG welding process compared to MIG welding, combination of TIG and MIG welding. Hardness values are observed to be higher at the weld region than the base material. Tensile test results show that the ultimate tensile strength of welded plate is greater than that of base materials and TIG welding process is better than other two processes. The microstructure images show that there is a continuous and uniform welding and the joint is defect free from cracks.


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