Analysis of Filler Metal Composition on Weld Dilution of Austenitic Stainless Steel by TIG and MIG Welding

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.

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.


Otopro ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 18
Author(s):  
Nidia Lestari

Austenitic stainless steel or commonly known as AISI 304 stainless steel has advantages, including good ductility at relatively low temperatures and high resistance to corrosion. These properties make Austenitic Stainless Steel a candidate material for use in pipe fabrication systems, automotive exhaust gas systems and some equipment related to the chemical and nuclear industry. Therefore, it is necessary to analyze the variation of welding currents on the strength of the welds in the application of Shielded Metal Arc Welding (SMAW) on stainless steel. The electrodes used are E308-16 types with current variations of 90 amperes, 100 amperes and 110 amperes. The results showed that the electric current factor in the SMAW welding process greatly influenced the welding results in terms of its strength. The highest mechanical strength was obtained at welding current of 110 Ampere, with a heat input of 976.067 J / mm, an average mechanical strength of 68.438 kg / mm2 for tensile stress and strain of 47.451% in the tensile test, and an average value of hardness of 225.008 HV for hardness test in weld.


Author(s):  
Dixit Patel ◽  
Suketu Jani ◽  
Vivek Singh ◽  
Som Ashutosh

Abstract Chromium manganese austenitic stainless steel is exhibiting an admirable amalgamation of higher strength and stress corrosion resistance. This economical steel is developed to fulfill the requirement of a variety of consumers for high temperature and structural applications. Hitherto, the limitation associate with the TIG welding process is a low depth of penetration which reduces productivity. Activated tungsten inert gas welding (ATIG) is the best suitable option to overcome this problem and satisfy the sustainable welding requirement. Welding procedure has been developed for chromium manganese austenitic stainless steel during ATIG welding using a box behken design (BBD) to improve penetration depth and productivity. The activated flux using SiO2 and TiO2 flux indicates improvement in penetration 5.3 mm and 5.1 mm as compared to TIG welding. The ATIG welded test coupon has strength and hardness of 495 MPa and 195 HV when using SiO2 flux, and 487 MPa and 190 HV when using TiO2 flux, compared to 435 MPa and 165HV for the TIG welded test coupon. ATIG welds have higher strength and hardness because of their finer grain size when compared to TIG welded test coupons.


Author(s):  
Mária Dománková ◽  
Marek Adamech ◽  
Jana Petzová ◽  
Katarína Bártová ◽  
Peter Pinke

Abstract Borated austenitic stainless steel is used in nuclear industry due to the high neutron absorption efficiency. The plasma, laser and electron beam welding experiments were used for the study of the weld joints microstructure. The microstructure changes caused by welding process were observed by light optical microscopy and transmission electron microscopy. The microstructural characterization and microchemical analysis showed significant changes of the phase composition in the weld metal mainly. The austenitic dendrites were surrounded by eutectics, which were the mixture of the M2(C,B) and M23(C,B) borocarbides, δ-ferrite and austenite.


2017 ◽  
Vol 904 ◽  
pp. 19-23
Author(s):  
Van Nhat Nguyen ◽  
Quoc Manh Nguyen ◽  
Dang Thi Huong Thao ◽  
Shyh Chour Huang

Welding dissimilar materials has been widely applied in industries. Some of them are considered this as a strategy to develop their future technology products. Aluminum alloy and stainless steel have differences in physical, thermal, mechanical and metallurgic properties. However, selecting a suitable welding process and welding rods can solve this problem. This research aimed to investigate the T-joint welding between A6061 aluminum alloy and SUS304 stainless steel using new welding rods, Aluma-Steel by the Tungsten Inert Gas (TIG) welding process. The mechanical properties, the characteristics of microstructure, and component analysis of the welds have been investigated by the mechanical testing, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). As a result, the fracture occurred at the adjacent area between welding seam and A6061 alloys plate. The thermal cracking appeared at central welding-seam along the base metals if high welding current. A large amount of copper elements found in the welds due to using the new welding rod, Aluma-Steel rod.


2009 ◽  
Vol 410-411 ◽  
pp. 87-96 ◽  
Author(s):  
Markku Keskitalo ◽  
Kari Mäntyjärvi

The laser weldability of austenitic stainless steel (ASS) is good because of the material’s high absorptivity and favourable microstructure. There can be a slight possibility of solidification cracking at high welding speeds and low Crekv/Niekv ratios. Test welds were welded with a Yb:YAG disc laser. The test material was 3.2 mm EN 1.4404 2H C700 type stainless steel plate which was work hardened by cold rolling. The test materials were welded with different heat inputs ranging from 0.024 kJ/mm to 0.12 kJ/mm and with 300 mm and 200 mm focal lengths. The weld seams were square-groove welded as butt weld without filler material. The edges of the groove were made by mechanical or laser cutting. The hardness profiles from cross-sections of the welds were measured with a Vickers microhardness tester using 200 g weight. The mechanical properties were tested with tensile tests. The welds were classified with radiographic verification by an accredited laboratory. A number of the welds were fatigue tested with a bending fatigue tester. The mechanical properties (Rp 0.2%, Rm) of the laser welds were almost the same as in the base material except at the highest heat input. In the radiographic classification, the welds which were welded to the laser-cut edge were classified as class B (accepted). The other welds were classified as class D or C (rejected). The main reasons for the rejection of welds made on mechanically cut edges were lack of penetration or undercut of the weld. A problem with mechanically cut edges, and hence the welds, is that they can be non-square and bent edge. Fatigue tests and tensile tests gave no evidence of solidification cracking in the microstructure of the solidified parts of the welds.


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