The Experts below are selected from a list of 243 Experts worldwide ranked by ideXlab platform
G. Madhusudhan Reddy - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Welding Consumables on Fatigue Performance of Shielded Metal Arc Welded High Strength, Q&T Steel Joints
Journal of Materials Engineering and Performance, 2009Co-Authors: Govindaraj Magudeeswaran, Venkatesh Balasubramanian, G. Madhusudhan ReddyAbstract:Quenched and Tempered (Q&T) Steels are widely used in the construction of military vehicles due to their high strength-to-weight ratio and high hardness. These Steels are prone to hydrogen-induced cracking in the heat affected zone (HAZ) after welding. The use of austenitic stainless Steel consumables to weld the above Steel was the only remedy because of higher solubility for hydrogen in austenitic phase. Recent studies proved that high Nickel Steel and low hydrogen ferritic Steel consumables can be used to weld Q&T Steels, which can give very low hydrogen levels in the weld deposits. In this investigation an attempt has been made to study the effect of welding consumables on high cycle fatigue properties of high strength, Q&T Steel joints. Three different consumables namely (i) austenitic stainless Steel, (ii) low hydrogen ferritic Steel, and (iii) high Nickel Steel have been used to fabricate the joints by shielded metal arc (SMAW) welding process. The joints fabricated using low hydrogen ferritic Steel electrodes showed superior fatigue properties than other joints.
Myunghyun Kim - One of the best experts on this subject based on the ideXlab platform.
-
effects of the welding process and consumables on the fracture behavior of 9 wt Nickel Steel
Experimental Techniques, 2020Co-Authors: Bohye Kim, Junik Park, Junshin Lee, Jaekon Lee, Myunghyun KimAbstract:In recent years, stringent environmental regulations for air pollution have led to increased demand for liquefied natural gas (LNG). Therefore, the demand for the design and construction of LNG-fueled vessels has also increased. One of the most important points for the design of LNG-fueled vessels is the structural integrity of the LNG fuel tank, particularly at cryogenic temperatures. Low temperature materials are used in the construction of LNG fuel tanks to ensure structural safety. Among the various low temperature materials, Nickel Steel is commonly employed for the design of LNG storage tanks. In addition, Shielded Metal Arc Welding (SMAW) and Submerged Arc Welding (SAW) are commonly applied to the construction of LNG storage tanks. On the other hand, the application of Flux Cored Arc Welding (FCAW) for Nickel Steel as an alternative to SMAW and SAW appears to be necessary, considering the high productivity. Nevertheless, there have been few studies of the fracture behavior of Nickel Steel with FACW compared to SMAW and SAW processes. This study examined the fracture characteristics of 9% Nickel Steel and weldments considering application for the LNG storage tanks. The fracture characteristics of FCAW was compared with SMAW at 25°C and − 163°C temperatures. As the result, the mechanical properties with FCAW were higher than those with SMAW at 25°C and − 163°C. In addition, SMAW is slightly better than FCAW in terms of the impact absorbed energy. Moreover, the crack tip opening displacement (CTOD) values of the weld metal and heat affected zone (HAZ) with FCAW were higher than those with SMAW.
-
Effects of the Welding Process and Consumables on the Fracture Behavior of 9 Wt.% Nickel Steel
Experimental Techniques, 2019Co-Authors: Bohye Kim, Junshin Lee, Jaekon Lee, Jung-im Park, Myunghyun KimAbstract:In recent years, stringent environmental regulations for air pollution have led to increased demand for liquefied natural gas (LNG). Therefore, the demand for the design and construction of LNG-fueled vessels has also increased. One of the most important points for the design of LNG-fueled vessels is the structural integrity of the LNG fuel tank, particularly at cryogenic temperatures. Low temperature materials are used in the construction of LNG fuel tanks to ensure structural safety. Among the various low temperature materials, Nickel Steel is commonly employed for the design of LNG storage tanks. In addition, Shielded Metal Arc Welding (SMAW) and Submerged Arc Welding (SAW) are commonly applied to the construction of LNG storage tanks. On the other hand, the application of Flux Cored Arc Welding (FCAW) for Nickel Steel as an alternative to SMAW and SAW appears to be necessary, considering the high productivity. Nevertheless, there have been few studies of the fracture behavior of Nickel Steel with FACW compared to SMAW and SAW processes. This study examined the fracture characteristics of 9% Nickel Steel and weldments considering application for the LNG storage tanks. The fracture characteristics of FCAW was compared with SMAW at 25°C and − 163°C temperatures. As the result, the mechanical properties with FCAW were higher than those with SMAW at 25°C and − 163°C. In addition, SMAW is slightly better than FCAW in terms of the impact absorbed energy. Moreover, the crack tip opening displacement (CTOD) values of the weld metal and heat affected zone (HAZ) with FCAW were higher than those with SMAW.
-
A Comparison of Fracture Toughness and Fatigue Crack Propagation Characteristics of High Manganese and Nickel Steels
Volume 4: Materials Technology, 2018Co-Authors: J.y. Park, Myunghyun KimAbstract:Recently, demands for liquefied natural gas (LNG) are increased by developing countries such as China, India and Middle East area. In addition, the International Maritime Organization (IMO) reinforced regulations to avoid the serious environmental pollution. This trend has led to manufacturing and operating various LNG vessels such as liquefied natural gas carrier (LNGC), floating liquefied natural gas (FLNG) and very large gas carrier (VLGC). In the design of LNG vessels, the structural integrity of LNG storage tank is of significant importance to satisfy the service conditions. In order to secure structural integrity, LNG storage tank is fabricated with low temperature materials. In general, low temperature materials such as SUS304L, Invar alloy, Al 5083-O, Nickel alloy Steel and high manganese Steel exhibit excellent fatigue and fracture performances at cryogenic temperature. In particular, high manganese Steel has attracted interest because they are potentially less expensive than the competing other low temperature materials. This study compares the fracture toughness and fatigue crack growth characteristics of high manganese Steel with those of Nickel Steels. In addition, fracture toughness and fatigue crack growth rate tests for various Nickel Steels are conducted according to BS 7448 and ASTM E647, respectively. In order to obtain less conservative design values, the results of high manganese Steel and various Nickel Steels were compared to those of BS7910. As a result, the CTOD value of high manganese Steel is higher than that of 9% Nickel Steel at cryogenic temperature. In case of FCGR, the high manganese Steel and 9% Nickel Steel are found to be similar to each other.
-
An Experimental Study for Fatigue Performance of 7% Nickel Steels for Type B Liquefied Natural Gas Carriers
Journal of Offshore Mechanics and Arctic Engineering, 2016Co-Authors: Youngwoo Kim, Byeong-jae Noh, Jae-myung Lee, Hee Joon Sung, Ryuichi Ando, Toshiyuki Matsumoto, Myunghyun KimAbstract:Structural safety is one of the most important issues associated with liquefied natural gas (LNG) storage systems, such as LNG carriers, LNG Floating Production Storage Offloading (FPSO), and Floating Storage Regasification Unit (FSRU). One of the most common materials for the LNG storage systems has been 9% Nickel Steel over the last 50 years as it has excellent mechanical properties under cryogenic temperature. Recently, there have been efforts for lowering the Nickel content due to the increased Nickel price as well as the high price of Nickel based welding consumables. In this respect, 7% Nickel Steels are recently developed for reducing the associated costs mainly for cryogenic applications. The newly developed 7% Nickel Steels are known to have improved toughness comparable to that of 9% Nickel Steels by thermomechanical control process (TMCP) and micro-alloying technology. The main objective of this study is to evaluate the fatigue performance of 7% Nickel Steels with a special attention to type B LNG carrier applications. Cyclic fatigue and fatigue crack growth rate (FCGR) tests for 7% Nickel Steels were conducted at room and cryogenic temperatures. Fatigue tests were carried out with three different types of specimens such as base metal, butt weld, and fillet weld to characterize the fatigue properties at various locations. In addition, FCGR tests were carried out using compact tension (C(T)) specimens. The difference of FCGR characteristics among base, weld, and heat affected zone (HAZ) is investigated. The fatigue and FCGR test results of 7% Nickel Steels are evaluated and compared with reference data of 9% Nickel Steel. Based on this study, it is observed that the 7% Nickel Steel exhibits similar fatigue performance in comparison with that of 9% Nickel Steel.
-
An Investigation of the Mechanical Properties of a Weldment of 7% Nickel Alloy Steels
MDPI AG, 2016Co-Authors: J.y. Park, Jae-myung Lee, Myunghyun KimAbstract:During the last decade, the demand for natural gas has steadily increased for the prevention of environmental pollution. For this reason, many liquefied natural gas (LNG) carriers have been manufactured. Since one of the most important issues in the design of LNG carriers is to guarantee structural safety, the use of low-temperature materials is increasing. Among commonly employed low-temperature materials, Nickel Steel has many benefits such as good strength and outstanding corrosion resistance. Accordingly, Nickel Steels are one of the most commonly used low-temperature Steels for LNG storage tanks. However, the study of fracture toughness with various welding consumables of 7% Nickel alloy Steel is insufficient for ensuring the structural safety of LNG storage tanks. Therefore, the aim of this study was to evaluate fracture toughness of several different weldments for 7% Nickel alloy Steels. The weldment of 7% Nickel alloy Steel was fabricated by tungsten inert gas (TIG), flux cored arc welding (FCAW), and gas metal arc welding (GMAW). In order to assess the material performance of the weldments at low temperature, fracture toughness such as crack tip opening displacement (CTOD) and the absorbed impact energy of weldments were compared with those of 9% Nickel Steel weldments
Govindaraj Magudeeswaran - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Welding Consumables on Fatigue Performance of Shielded Metal Arc Welded High Strength, Q&T Steel Joints
Journal of Materials Engineering and Performance, 2009Co-Authors: Govindaraj Magudeeswaran, Venkatesh Balasubramanian, G. Madhusudhan ReddyAbstract:Quenched and Tempered (Q&T) Steels are widely used in the construction of military vehicles due to their high strength-to-weight ratio and high hardness. These Steels are prone to hydrogen-induced cracking in the heat affected zone (HAZ) after welding. The use of austenitic stainless Steel consumables to weld the above Steel was the only remedy because of higher solubility for hydrogen in austenitic phase. Recent studies proved that high Nickel Steel and low hydrogen ferritic Steel consumables can be used to weld Q&T Steels, which can give very low hydrogen levels in the weld deposits. In this investigation an attempt has been made to study the effect of welding consumables on high cycle fatigue properties of high strength, Q&T Steel joints. Three different consumables namely (i) austenitic stainless Steel, (ii) low hydrogen ferritic Steel, and (iii) high Nickel Steel have been used to fabricate the joints by shielded metal arc (SMAW) welding process. The joints fabricated using low hydrogen ferritic Steel electrodes showed superior fatigue properties than other joints.
-
Effect of welding consumables on hydrogen induced cracking of armour grade quenched and tempered Steel welds
Ironmaking & Steelmaking, 2008Co-Authors: Govindaraj Magudeeswaran, Venkatesh Balasubramanian, G. Madhusudhan ReddyAbstract:Abstract Armour grade quenched and tempered (Q&T) Steels are susceptible to hydrogen induced cracking (HIC) in the heat affected zone after welding. Austenitic stainless Steel (ASS) consumables are selected for welding Q&T Steels as they have higher solubility for hydrogen in the austenitic phase and it is the most beneficial method for controlling HIC in Q&T Steel welds. Recent studies reveal that high Nickel Steel and low hydrogen ferritic Steel consumables can be used to weld Q&T Steels, which can give very low hydrogen levels in the weld deposits. In this investigation, an attempt has been made to study the effect of welding consumables on hydrogen induced cracking of Q&T Steel welds by implant testing. Shielded metal arc (SMAW) welding process has been used for making welds using three different consumables, namely austenitic stainless Steel, low hydrogen ferritic Steel (LHF) and high Nickel Steel (HNS) to assess HIC by implant testing. The high Nickel Steel consumables exhibited a higher value of lo...
Venkatesh Balasubramanian - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Welding Consumables on Fatigue Performance of Shielded Metal Arc Welded High Strength, Q&T Steel Joints
Journal of Materials Engineering and Performance, 2009Co-Authors: Govindaraj Magudeeswaran, Venkatesh Balasubramanian, G. Madhusudhan ReddyAbstract:Quenched and Tempered (Q&T) Steels are widely used in the construction of military vehicles due to their high strength-to-weight ratio and high hardness. These Steels are prone to hydrogen-induced cracking in the heat affected zone (HAZ) after welding. The use of austenitic stainless Steel consumables to weld the above Steel was the only remedy because of higher solubility for hydrogen in austenitic phase. Recent studies proved that high Nickel Steel and low hydrogen ferritic Steel consumables can be used to weld Q&T Steels, which can give very low hydrogen levels in the weld deposits. In this investigation an attempt has been made to study the effect of welding consumables on high cycle fatigue properties of high strength, Q&T Steel joints. Three different consumables namely (i) austenitic stainless Steel, (ii) low hydrogen ferritic Steel, and (iii) high Nickel Steel have been used to fabricate the joints by shielded metal arc (SMAW) welding process. The joints fabricated using low hydrogen ferritic Steel electrodes showed superior fatigue properties than other joints.
-
Effect of welding consumables on hydrogen induced cracking of armour grade quenched and tempered Steel welds
Ironmaking & Steelmaking, 2008Co-Authors: Govindaraj Magudeeswaran, Venkatesh Balasubramanian, G. Madhusudhan ReddyAbstract:Abstract Armour grade quenched and tempered (Q&T) Steels are susceptible to hydrogen induced cracking (HIC) in the heat affected zone after welding. Austenitic stainless Steel (ASS) consumables are selected for welding Q&T Steels as they have higher solubility for hydrogen in the austenitic phase and it is the most beneficial method for controlling HIC in Q&T Steel welds. Recent studies reveal that high Nickel Steel and low hydrogen ferritic Steel consumables can be used to weld Q&T Steels, which can give very low hydrogen levels in the weld deposits. In this investigation, an attempt has been made to study the effect of welding consumables on hydrogen induced cracking of Q&T Steel welds by implant testing. Shielded metal arc (SMAW) welding process has been used for making welds using three different consumables, namely austenitic stainless Steel, low hydrogen ferritic Steel (LHF) and high Nickel Steel (HNS) to assess HIC by implant testing. The high Nickel Steel consumables exhibited a higher value of lo...
Sang Chod - One of the best experts on this subject based on the ideXlab platform.
-
Improvement of hot cracking susceptibility and productivity using Super-TIG welding for 9% Nickel-Steel
Zavarivanje i zavarene konstrukcije, 2020Co-Authors: Muralimohan Cheepua, Jung Parkb, Hyo Baekc, Sang ChodAbstract:9% Nickel Steel has been widely used for storage of liquefied gases, oxygen, and nitrogen in competition with aluminium and austenitic alloys due to its low cost. The development of 9% Nickel Steel with low ductile-brittle transition temperatures reformed the LNG industry by extensive storage and transportation. In recent years, the demand for 9% Nickel Steel fuel tanks increasing due to the International Maritime Organization regulations on the reduction of sulphur oxides from 3.5% to 0.5%. Hence, the LNG fuel tanks made with 9% Nickel Steel became a major part of the international energy industry. However, the weldability, fabrication cost, and productivity of these Steels are one of the major concerns for manufacturers. Flux cored arc welding (FCAW) process is the most commonly used joining method for 9% Nickel Steel with Hastelloy fillers. In FCAW, the loss of deposited metal due to inter pass cleaning by grinding action caused to a reduction in total productivity. Demands for higher production, low cost, better mechanical properties, and reliability are the main driving forces for new developments in this area. To achieve these, the most recently developed "Super-TIG Welding" with C-type filler was successfully applied to improve the 9% Nickel Steel weldability, productivity and, mechanical and metallurgical properties of the butt welds. In SuperTIG welding, alloy 625 filler was used, which is cheaper and good weldability over the Hastelloy fillers. The weldability evaluation tests resulted in improved resistance to hot cracking susceptibility using Super-TIG welding. The mechanical properties of the Super-TIG welded joints performed better than the FCAW joints. Most importantly, the productivity of the welding dramatically improved by Super-TIG welding. Super-TIG welding is capable of producing higher feeding rates with clean beads. Therefore, the alloy 625 C-Filler and avoidance of inter pass cleaning in Super-TIG welding resulting in increased productivity. The newly developed Super-TIG welding achieved many things to obtain satisfactory products in the recent welding industry.