Specification for Class I arc welding of austenitic stainless steel pipework for carrying fluids

2015 ◽  
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Arc Welding ◽  
Class I

Effect of TIG Welding and Manual Metal Arc Welding on Mechanical Properties of AISI 304 and 316L Austenitic Stainless Steel Sheets

2017 ◽  
Vol 750 ◽  
pp. 26-33
Author(s):  
Alaa Abu Harb ◽  
Ion Ciuca ◽  
Robert Ciocoiu ◽  
Mihai Vasile ◽  
Adrian Bibis ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Arc Welding ◽  
Welding Process ◽  
Central Hole ◽  
Steel Sheets ◽  
Metal Arc Welding ◽  
316L Austenitic Stainless Steel ◽  
Better Than

The welding technique used for ASIS 304 and 316L austenitic stainless steel sheets both with a thickness of 3mm is gas tungsten arc welding (TIG) and manual metal arc welding (MMAW). Mechanical properties that were verified include: hardness test and tensile test before welding and after it. The welding process was done on two types of specimens: with a central hole and without hole. We concluded that there was a decrease in the properties of tensile for both specimens with central hole, and 316L had tensile characteristics better than 304 when using the technique TIG. As for 304, it had tensile characteristics better than 316L when using the technique MMAW. We also concluded that the existence of central holes had an influence on the hardness characteristics on both types. The hardness increased in 304 but decreased in 316L. The welding process also showed that there was no influence of MMAW on hardness on both specimens. However it showed that there was no influence of TIG on the hardness for 304, but for 316L values increased.

Welding and Fabrication of Stainless Steel Equipment for 500MWe Prototype Fast Breeder Reactor

2013 ◽  
Vol 794 ◽  
pp. 305-315
Author(s):  
Prabhat Kumar
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Arc Welding ◽  
Welding Distortion ◽  
Fast Breeder Reactor ◽  
Mandatory Requirement ◽  
Main Vessel ◽  
Grid Plate ◽  
Thin Walled ◽  
Inner Vessel

Austenitic stainless steel is the major structural material for the primary and secondary sodium systems (except for the steam generators) for the currently operating and planned fast reactors all over the world. The boundaries of sodium systems of Prototype Fast Breeder Reactor (PFBR) is designed so as to have an extremely low probability of leakage, rapidly propagating failure and gross rupture under the static & dynamic loads expected during various operating conditions.The degradation of material properties (e.g. effect of sodium, temperature and irradiation), transients, residual stresses, flaw size etc. are the important considerations, which shall be taken into account. The principal material of construction for PFBR is austenitic stainless steel of grade 316LN/304LN. The scope of welding and fabrication of PFBR components is too large due to versatile types of systems with varieties of components with complex constructional features. High operating temperature of various systems causing high stresses are to be minimized by designing thin walled structure. Most of the Nuclear Steam Supply System (NSSS) components are thin walled and require manufacturing in separate nuclear clean hall conditions to assure the quality.The welding with stringent tolerances along with high distortion in stainless steels due to high thermal expansion and low thermal conductivity makes the fabrication extremely challenging.The welding standards and acceptance criteria of PFBR equipment is stringent compared to other industrial specification. Manufacture of over dimensional components (diameter greater than 12m and thickness upto 40mm) such as MainVessel, Safety Vessel, Inner Vessel involves die pressing of large size dished end & conical petals. The solution annealing of cold worked petals is a mandatory requirement if strain exceeds 10%. Innovative welding techniques and many trials were conducted on mock up for establishing the process parameters. The forming techniques, bending methods and welding procedures were qualified with stringent non-destructive and destructive examinations and testing before taking up the actual job. Thermal Baffle has two large concentric cylindrical shells, inner and outer shells of about 12.4m diameter and fabrication is a challenging task. PFBR also involves dissimilar joint welding between carbon steel (A48P2) and austenitic stainless steel (316LN) at integration location of roof slab & main vessel. This welding is carried out by combination of Gas Tungsten Arc Welding (GTAW) & Shielded Metal Arc Welding (SMAW) processes using ER 309L & E 309-16 welding consumables with controlled heat input to minimize the dilution of carbon & distortion. The weld between primary pipe & grid plate cannot be accessed for in-service inspection and therefore requires extra-ordinary skilled welders. Space constraints & lack of accessibility makes the welding & inspection challenging. This paper highlights the welding and fabrication aspects of few major, over dimensional and critical equipment of 500MWe Prototype Fast Breeder Reactor. Keywords: Stainless Steel, Main Vessel, Safety Vessel, Inner Vessel, Grid Plate, PFBR, SS welding, distortion.

scholarly journals Effects of Electromagnetic Stirring on the Cast Austenitic Stainless Steel Weldments by Gas Tungsten Arc Welding

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 630 ◽  
Author(s):  
Sheng-Long Jeng ◽  
Dai-Ping Su ◽  
Jing-Ting Lee ◽  
Jiunn-Yuan Huang
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Grain Boundaries ◽  
Arc Welding ◽  
Gas Tungsten Arc Welding ◽  
Electromagnetic Stirring ◽  
Gas Tungsten Arc ◽  
Welding Defects ◽  
Gas Tungsten ◽  
Notched Tensile Strength

Cast austenitic stainless steel (CASS) often contains high contents of silicon, phosphorus, and sulfur to prompt low melting phases to form in the welds. As a result, welding defects can be induced to degrade the welds. This study’s purpose was to investigate the effects of electromagnetic stirring (EMS) on the CASS weldments. The results showed that the ferrites in the heat affected zone (HAZ) had tortuous grain boundaries, while those that were close to the fusion lines had transformed austenites. EMS could reduce the influence of the welding heat to make the grain boundaries less tortuous and the transformed austenites smaller. Although their temperature profiles were almost the same, the gas-tungsten-arc-welding (GTAW) weld had smaller grains with massive ferrite colonies and more precipitates, while the GTAW+EMS weld had denser ferrite colonies with multi-orientations, but fewer precipitates. The hardness of the base metals and HAZs were typically higher than that of the welds. For both of the welds, the root was the region with the highest hardness. The hardness decreased from the root to the cap regions along the thickness direction. The GTAW weld had a higher hardness than the GTAW+EMS weld. At room temperature, the GTAW+EMS weld had a higher notched tensile strength and elongation than the GTAW weld. This could be attributed to the observation that the GTAW+EMS weld had dense and intersecting dendrites and that more austenites were deformed during tensile testing.

scholarly journals Single sided single pass submerged arc welding of austenitic stainless steel

2007 ◽  
Vol 23 (9) ◽  
pp. 1039-1048 ◽  
Author(s):  
K. Chi ◽  
M. S. Maclean ◽  
N. A. McPherson ◽  
T. N. Baker
Keyword(s):  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Arc Welding ◽  
Submerged Arc Welding ◽  
Single Pass ◽  
Submerged Arc

scholarly journals Corrosion Behaviors of Super Austenitic Stainless Steel Weld Joints in the As-Welded and Post Weld Heat Treated States

2021 ◽  
Vol 59 (6) ◽  
pp. 374-383
Author(s):  
Dong min Cho ◽  
Jin-seong Park ◽  
Won Ki Jeong ◽  
Seung Gab Hong ◽  
Sung Jin Kim
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Pitting Corrosion ◽  
Arc Welding ◽  
Sigma Phase ◽  
Inconel 625 ◽  
Gas Tungsten Arc ◽  
Corrosion Behaviors ◽  
Super Austenitic Stainless Steel

The corrosion behaviors of a combined weld (plasma, gas tungsten arc) joint in a super austenitic stainless steel pipe were investigated using a range of experimental and analytical methods. To ensure superior corrosion resistance, a Ni-based super alloy (Inconel 625) was employed as the welding material only in the gas tungsten arc welding (GTAW). Nevertheless, pitting corrosion occurred preferentially around the sigma phase which had been precipitated in the interdendritic region of the GTAW. This indicated that the Inconel 625, which has a higher pitting resistance equivalent number (PREN), became even more susceptible to pitting corrosion than the base metal (BM). The higher Fe content in the Inconel 625 due to the dilution of Fe, supplied by the leading plasma arc welding, may increase the driving force for the precipitation of sigma phase. It was also revealed that the post weld heat treatment conducted at 1050~1150 oC effectively reduced the fraction of sigma phase precipitated in the weld. Even after such heat treatment, however, pitting corrosion occurred unexpectedly in the center region of the BM. This may be due to additional precipitation of the sigma phase in the BM, caused by inadequate control of the cooling rate during heat treatment at the industrial site.

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